Re: [U-Boot] [PATCH 01/11] DM: add block device core
On Saturday 22 September 2012 15:59:46 Pavel Herrmann wrote: On Saturday 22 of September 2012 15:33:10 Marek Vasut wrote: Dear Pavel Herrmann, On Saturday 22 of September 2012 02:09:15 Marek Vasut wrote: Dear Pavel Herrmann, [...] one or none - requests on USB flashes should not pass through block_controller_driver. Uh, what do they pass into then ? their parent (an USB hub) block_device instance (aka. partition/disk) directly connected to USB hub instance does not seem right. why? It doesn't make sense ... you need some kind of interim controller (like the chip between the USB and NAND in the thumbdrive. yes, but you dont make drivers for every chip there is, instead the chips understand a common language, where you describe block operations by USB transfers, and that is exactly what saib block_device_usb_flash would do. every child of block_controller should be a block_device (not necessarily the other way around I doubt it's even possible to be the other way around. ), so there is no way you pass more instances block_controller on your way up. Ok, let me explain again. Let's look at the USB case to make it more real-world- ish. Imagine you have a thumb drive with 2 partitions. Thus you have two instances of struct block_device [denote BDp] for the partitions and one more for the whole disc [denote BDd]. When you read from partition, you end up poking BDp, which pushes the request up into BDd. This in turn calls USB-flashdisc- block_controller_driver [call it UFc]. For flash disc to read data, it needs to do some USB transfers. These are provided by USB host controller [UHC]. Thus you need some glue between UHC and UFc ... this is what I'm talking about. there should be no UFc, your BDd driver should talk directly to your UHC So my generic partition implementation (BDd) would have to implement USB flashdisc stuff, correct? This makes no sense. no. your generic USB flash would have to implement USB flashdisc stuff, your generic partition implements block_device operations on top of other block_device (aka diosk, memory card, USB flash) Ok, so in your parlance, the block_device is either partition/disc or a SD card controller driver or USB flashdisc driver ? You are mixing these two things together? please read the letters you came up with right. (maybe after getting some sleep by the looks of it) I'd prefer to read some documented code. im missing the point of this. you stateted that you have a partition BDp and a disk BDd. i said your BDd will sit above USB API, and you stared ranting about partitions implementing USB stuff, which was totaly off. the point you are not getting is that there should be more block_device drivers than there is now - one for partitions, one for disk, one for USB flash, one for SD and so on, each one using a different parent API Ok, now I understand your intention. Split it -- make partitions separate, since this is flat out confusing! Make partitions / whole disc a separate thing ... Make USB flash driver / SD card driver / etc. another thing ... You can not mix these two together, it makes no sense. well, disks, SD cards and USB flashes are one thing at the moment (see struct block_dev_desc). i am only adding partitions to the mix. (a driver that has blockdev API on one end, USB on the other) Ok, so how would this work, every partition implementation implements upcalls for all USB, SCSI, SATA, IDE, SD, ... and gazilion other types of drive it can sit on? no, partition only implements call onto another block device Ok, I see the issue at hand. In case of a regular drive, this implements the IO directly. In case of SD, this is a proxy object which interfaces with some SD-library and prepares the SD commands and then pushes that up into the controller to do the job? Same thing for USB flashes ? not every block device will have a block controller as a parent (or parent-of- parent in case of a partition). there would be a blockdev-usb that has a USB hub as a parent, and a blockdev-mmc, that has a mmc/sdio controller as a parent. So you would have a specific partition implementation for SD, SATA, IDE, SCSI, USB ... ? This is flawed. no, read above The partition should be a generic thing which knows nothing about where it's sitting at. So is the whole drive, same thing, it just has partitions hooked under it. I'd expect a block_controller to be the proxy object under which the block_device representing the disc is connected. And this block_controller to be proxifying the
Re: [U-Boot] [PATCH 01/11] DM: add block device core
On Saturday 22 of September 2012 02:09:15 Marek Vasut wrote: Dear Pavel Herrmann, [...] one or none - requests on USB flashes should not pass through block_controller_driver. Uh, what do they pass into then ? their parent (an USB hub) block_device instance (aka. partition/disk) directly connected to USB hub instance does not seem right. why? every child of block_controller should be a block_device (not necessarily the other way around I doubt it's even possible to be the other way around. ), so there is no way you pass more instances block_controller on your way up. Ok, let me explain again. Let's look at the USB case to make it more real-world- ish. Imagine you have a thumb drive with 2 partitions. Thus you have two instances of struct block_device [denote BDp] for the partitions and one more for the whole disc [denote BDd]. When you read from partition, you end up poking BDp, which pushes the request up into BDd. This in turn calls USB-flashdisc- block_controller_driver [call it UFc]. For flash disc to read data, it needs to do some USB transfers. These are provided by USB host controller [UHC]. Thus you need some glue between UHC and UFc ... this is what I'm talking about. there should be no UFc, your BDd driver should talk directly to your UHC So my generic partition implementation (BDd) would have to implement USB flashdisc stuff, correct? This makes no sense. no. your generic USB flash would have to implement USB flashdisc stuff, your generic partition implements block_device operations on top of other block_device (aka diosk, memory card, USB flash) please read the letters you came up with right. (maybe after getting some sleep by the looks of it) the point you are not getting is that there should be more block_device drivers than there is now - one for partitions, one for disk, one for USB flash, one for SD and so on, each one using a different parent API (a driver that has blockdev API on one end, USB on the other) Ok, so how would this work, every partition implementation implements upcalls for all USB, SCSI, SATA, IDE, SD, ... and gazilion other types of drive it can sit on? no, partition only implements call onto another block device Ok, I see the issue at hand. In case of a regular drive, this implements the IO directly. In case of SD, this is a proxy object which interfaces with some SD-library and prepares the SD commands and then pushes that up into the controller to do the job? Same thing for USB flashes ? not every block device will have a block controller as a parent (or parent-of- parent in case of a partition). there would be a blockdev-usb that has a USB hub as a parent, and a blockdev-mmc, that has a mmc/sdio controller as a parent. So you would have a specific partition implementation for SD, SATA, IDE, SCSI, USB ... ? This is flawed. no, read above The partition should be a generic thing which knows nothing about where it's sitting at. So is the whole drive, same thing, it just has partitions hooked under it. I'd expect a block_controller to be the proxy object under which the block_device representing the disc is connected. And this block_controller to be proxifying the requests to the respective drivers (be it SD, SATA, whatever). your idea is wrong - you expect there will always be only one block_device representig a disk, and all the proxy would be done by the block_controller above it. this is not true Pavel Herrmann ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
Dear Pavel Herrmann, On Saturday 22 of September 2012 02:09:15 Marek Vasut wrote: Dear Pavel Herrmann, [...] one or none - requests on USB flashes should not pass through block_controller_driver. Uh, what do they pass into then ? their parent (an USB hub) block_device instance (aka. partition/disk) directly connected to USB hub instance does not seem right. why? It doesn't make sense ... you need some kind of interim controller (like the chip between the USB and NAND in the thumbdrive. every child of block_controller should be a block_device (not necessarily the other way around I doubt it's even possible to be the other way around. ), so there is no way you pass more instances block_controller on your way up. Ok, let me explain again. Let's look at the USB case to make it more real-world- ish. Imagine you have a thumb drive with 2 partitions. Thus you have two instances of struct block_device [denote BDp] for the partitions and one more for the whole disc [denote BDd]. When you read from partition, you end up poking BDp, which pushes the request up into BDd. This in turn calls USB-flashdisc- block_controller_driver [call it UFc]. For flash disc to read data, it needs to do some USB transfers. These are provided by USB host controller [UHC]. Thus you need some glue between UHC and UFc ... this is what I'm talking about. there should be no UFc, your BDd driver should talk directly to your UHC So my generic partition implementation (BDd) would have to implement USB flashdisc stuff, correct? This makes no sense. no. your generic USB flash would have to implement USB flashdisc stuff, your generic partition implements block_device operations on top of other block_device (aka diosk, memory card, USB flash) Ok, so in your parlance, the block_device is either partition/disc or a SD card controller driver or USB flashdisc driver ? You are mixing these two things together? please read the letters you came up with right. (maybe after getting some sleep by the looks of it) I'd prefer to read some documented code. the point you are not getting is that there should be more block_device drivers than there is now - one for partitions, one for disk, one for USB flash, one for SD and so on, each one using a different parent API Ok, now I understand your intention. Split it -- make partitions separate, since this is flat out confusing! Make partitions / whole disc a separate thing ... Make USB flash driver / SD card driver / etc. another thing ... You can not mix these two together, it makes no sense. (a driver that has blockdev API on one end, USB on the other) Ok, so how would this work, every partition implementation implements upcalls for all USB, SCSI, SATA, IDE, SD, ... and gazilion other types of drive it can sit on? no, partition only implements call onto another block device Ok, I see the issue at hand. In case of a regular drive, this implements the IO directly. In case of SD, this is a proxy object which interfaces with some SD-library and prepares the SD commands and then pushes that up into the controller to do the job? Same thing for USB flashes ? not every block device will have a block controller as a parent (or parent-of- parent in case of a partition). there would be a blockdev-usb that has a USB hub as a parent, and a blockdev-mmc, that has a mmc/sdio controller as a parent. So you would have a specific partition implementation for SD, SATA, IDE, SCSI, USB ... ? This is flawed. no, read above The partition should be a generic thing which knows nothing about where it's sitting at. So is the whole drive, same thing, it just has partitions hooked under it. I'd expect a block_controller to be the proxy object under which the block_device representing the disc is connected. And this block_controller to be proxifying the requests to the respective drivers (be it SD, SATA, whatever). your idea is wrong - you expect there will always be only one block_device representig a disk, and all the proxy would be done by the block_controller above it. this is not true Any amount of block_device can be connected under the block_controller. Given that block_device is a partition/disc _only_ and block_controller is the interface driver ... which is probably not true, so you lost me again. I stop here, this discussion leads nowhere. Can you please write proper documentation from which I can get an idea how this exactly works? Ideally with diagrams ... doc/driver-model/UDM-block.txt would be a good place. Pavel Herrmann Best regards, Marek Vasut ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
On Saturday 22 of September 2012 15:33:10 Marek Vasut wrote: Dear Pavel Herrmann, On Saturday 22 of September 2012 02:09:15 Marek Vasut wrote: Dear Pavel Herrmann, [...] one or none - requests on USB flashes should not pass through block_controller_driver. Uh, what do they pass into then ? their parent (an USB hub) block_device instance (aka. partition/disk) directly connected to USB hub instance does not seem right. why? It doesn't make sense ... you need some kind of interim controller (like the chip between the USB and NAND in the thumbdrive. yes, but you dont make drivers for every chip there is, instead the chips understand a common language, where you describe block operations by USB transfers, and that is exactly what saib block_device_usb_flash would do. every child of block_controller should be a block_device (not necessarily the other way around I doubt it's even possible to be the other way around. ), so there is no way you pass more instances block_controller on your way up. Ok, let me explain again. Let's look at the USB case to make it more real-world- ish. Imagine you have a thumb drive with 2 partitions. Thus you have two instances of struct block_device [denote BDp] for the partitions and one more for the whole disc [denote BDd]. When you read from partition, you end up poking BDp, which pushes the request up into BDd. This in turn calls USB-flashdisc- block_controller_driver [call it UFc]. For flash disc to read data, it needs to do some USB transfers. These are provided by USB host controller [UHC]. Thus you need some glue between UHC and UFc ... this is what I'm talking about. there should be no UFc, your BDd driver should talk directly to your UHC So my generic partition implementation (BDd) would have to implement USB flashdisc stuff, correct? This makes no sense. no. your generic USB flash would have to implement USB flashdisc stuff, your generic partition implements block_device operations on top of other block_device (aka diosk, memory card, USB flash) Ok, so in your parlance, the block_device is either partition/disc or a SD card controller driver or USB flashdisc driver ? You are mixing these two things together? please read the letters you came up with right. (maybe after getting some sleep by the looks of it) I'd prefer to read some documented code. im missing the point of this. you stateted that you have a partition BDp and a disk BDd. i said your BDd will sit above USB API, and you stared ranting about partitions implementing USB stuff, which was totaly off. the point you are not getting is that there should be more block_device drivers than there is now - one for partitions, one for disk, one for USB flash, one for SD and so on, each one using a different parent API Ok, now I understand your intention. Split it -- make partitions separate, since this is flat out confusing! Make partitions / whole disc a separate thing ... Make USB flash driver / SD card driver / etc. another thing ... You can not mix these two together, it makes no sense. well, disks, SD cards and USB flashes are one thing at the moment (see struct block_dev_desc). i am only adding partitions to the mix. (a driver that has blockdev API on one end, USB on the other) Ok, so how would this work, every partition implementation implements upcalls for all USB, SCSI, SATA, IDE, SD, ... and gazilion other types of drive it can sit on? no, partition only implements call onto another block device Ok, I see the issue at hand. In case of a regular drive, this implements the IO directly. In case of SD, this is a proxy object which interfaces with some SD-library and prepares the SD commands and then pushes that up into the controller to do the job? Same thing for USB flashes ? not every block device will have a block controller as a parent (or parent-of- parent in case of a partition). there would be a blockdev-usb that has a USB hub as a parent, and a blockdev-mmc, that has a mmc/sdio controller as a parent. So you would have a specific partition implementation for SD, SATA, IDE, SCSI, USB ... ? This is flawed. no, read above The partition should be a generic thing which knows nothing about where it's sitting at. So is the whole drive, same thing, it just has partitions hooked under it. I'd expect a block_controller to be the proxy object under which the block_device representing the disc is connected. And this block_controller to be proxifying the requests to the respective drivers (be it SD, SATA, whatever). your idea is wrong - you expect there will always be only one block_device representig a disk, and all the proxy would be done by the
Re: [U-Boot] [PATCH 01/11] DM: add block device core
On Thursday 20 of September 2012 21:58:17 Marek Vasut wrote: Dear Pavel Herrmann, This core will register all block devices (disk, cards, partitons) and provide unfied access to them, instead of current method with device + partition offset Signed-off-by: Pavel Herrmann morpheus.i...@gmail.com --- Makefile | 1 + drivers/blockdev/Makefile | 42 include/dm/blockdev.h | 121 ++ 3 files changed, 164 insertions(+) create mode 100644 drivers/blockdev/Makefile create mode 100644 include/dm/blockdev.h Why not use drivers/block/ ? Because the drivers in drivers/block have a different purpose than blockdev. I would expect this question for blockctrl, there i just try to avoid confusion about being completely compatible Pavel Herrmann ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
Dear Pavel Herrmann, On Thursday 20 of September 2012 21:58:17 Marek Vasut wrote: Dear Pavel Herrmann, This core will register all block devices (disk, cards, partitons) and provide unfied access to them, instead of current method with device + partition offset Signed-off-by: Pavel Herrmann morpheus.i...@gmail.com --- Makefile | 1 + drivers/blockdev/Makefile | 42 include/dm/blockdev.h | 121 ++ 3 files changed, 164 insertions(+) create mode 100644 drivers/blockdev/Makefile create mode 100644 include/dm/blockdev.h Why not use drivers/block/ ? Because the drivers in drivers/block have a different purpose than blockdev. Different, ok. Can you elaborate how is it different? I would expect this question for blockctrl, there i just try to avoid confusion about being completely compatible Pavel Herrmann Best regards, Marek Vasut ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
On Friday 21 of September 2012 14:39:14 Marek Vasut wrote: Dear Pavel Herrmann, On Thursday 20 of September 2012 21:58:17 Marek Vasut wrote: Dear Pavel Herrmann, This core will register all block devices (disk, cards, partitons) and provide unfied access to them, instead of current method with device + partition offset Signed-off-by: Pavel Herrmann morpheus.i...@gmail.com --- Makefile | 1 + drivers/blockdev/Makefile | 42 include/dm/blockdev.h | 121 ++ 3 files changed, 164 insertions(+) create mode 100644 drivers/blockdev/Makefile create mode 100644 include/dm/blockdev.h Why not use drivers/block/ ? Because the drivers in drivers/block have a different purpose than blockdev. Different, ok. Can you elaborate how is it different? blockctrl is equivalent in purpose to drivers/block, just a new approach blockctrl = AHCI, PIIX... whichever chip you have between SATA and PCI (or generally disk-bus and board-bus) blockdev = disk, partition, SD card - something that does basic checks (range, possibility of operation) and submits operations to correct parent (blockctrl, MMC controller, whatnot). Also this gets rid of all partition-related code in filesystems, because the access to a partition and to the whole disk is the same, no need to manually compute offsets every time (and you can support discontinuous partitions, if you chose to do so) Pavel Herrmann ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
Dear Pavel Herrmann, On Friday 21 of September 2012 14:39:14 Marek Vasut wrote: Dear Pavel Herrmann, On Thursday 20 of September 2012 21:58:17 Marek Vasut wrote: Dear Pavel Herrmann, This core will register all block devices (disk, cards, partitons) and provide unfied access to them, instead of current method with device + partition offset Signed-off-by: Pavel Herrmann morpheus.i...@gmail.com --- Makefile | 1 + drivers/blockdev/Makefile | 42 include/dm/blockdev.h | 121 ++ 3 files changed, 164 insertions(+) create mode 100644 drivers/blockdev/Makefile create mode 100644 include/dm/blockdev.h Why not use drivers/block/ ? Because the drivers in drivers/block have a different purpose than blockdev. Different, ok. Can you elaborate how is it different? blockctrl is equivalent in purpose to drivers/block, just a new approach blockctrl = AHCI, PIIX... whichever chip you have between SATA and PCI (or generally disk-bus and board-bus) So this is for sata ? Or will it also by used for SD/USB flash discs? blockdev = disk, partition, SD card Uh, let's say I understand (even if I don't see the correlation between partition and SD card) - something that does basic checks (range, possibility of operation) and submits operations to correct parent (blockctrl, MMC controller, whatnot). Ascii art might help here greatly (how these pieces fall together). I think I do understand it though. Also this gets rid of all partition-related code in filesystems, because the access to a partition and to the whole disk is the same, no need to manually compute offsets every time (and you can support discontinuous partitions, if you chose to do so) Pavel Herrmann Best regards, Marek Vasut ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
On Friday 21 of September 2012 15:53:26 Marek Vasut wrote: Dear Pavel Herrmann, On Friday 21 of September 2012 14:39:14 Marek Vasut wrote: Dear Pavel Herrmann, On Thursday 20 of September 2012 21:58:17 Marek Vasut wrote: Dear Pavel Herrmann, This core will register all block devices (disk, cards, partitons) and provide unfied access to them, instead of current method with device + partition offset Signed-off-by: Pavel Herrmann morpheus.i...@gmail.com --- Makefile | 1 + drivers/blockdev/Makefile | 42 include/dm/blockdev.h | 121 ++ 3 files changed, 164 insertions(+) create mode 100644 drivers/blockdev/Makefile create mode 100644 include/dm/blockdev.h Why not use drivers/block/ ? Because the drivers in drivers/block have a different purpose than blockdev. Different, ok. Can you elaborate how is it different? blockctrl is equivalent in purpose to drivers/block, just a new approach blockctrl = AHCI, PIIX... whichever chip you have between SATA and PCI (or generally disk-bus and board-bus) So this is for sata ? Or will it also by used for SD/USB flash discs? no, blockctrl will be used for SATA, PATA, SCSI, and anything of the sort (device with several ports, block devices on said ports, ability to send read/write/query commands to devices on ports - definitely not USB, possibly also SD, but you probably want more operations from SD) blockdev = disk, partition, SD card Uh, let's say I understand (even if I don't see the correlation between partition and SD card) they are an ordered bunch of blocks with a conventional filesystem on them - something that does basic checks (range, possibility of operation) and submits operations to correct parent (blockctrl, MMC controller, whatnot). Ascii art might help here greatly (how these pieces fall together). I think I do understand it though. current code user - FS - offset calculation from partition info - drivers/disk new code user - FS - blockdev - blockctrl (or USB or SD controller) partition blockdev does all the offset calculation and range check that FSs do now, and then submits the operation to the parent blockdev, which in turn submits it to blockctrl (or an SD controller in case of a SD card, or USB controller in case of a USB flash) Pavel Herrmann ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
Dear Pavel Herrmann, [...] blockctrl = AHCI, PIIX... whichever chip you have between SATA and PCI (or generally disk-bus and board-bus) So this is for sata ? Or will it also by used for SD/USB flash discs? no, blockctrl will be used for SATA, PATA, SCSI, and anything of the sort (device with several ports, block devices on said ports, ability to send read/write/query commands to devices on ports - definitely not USB, possibly also SD, but you probably want more operations from SD) Why not USB flash ? Why not SD, what other stuff do you need for that? Is the API not misdesigned then? blockdev = disk, partition, SD card Uh, let's say I understand (even if I don't see the correlation between partition and SD card) they are an ordered bunch of blocks with a conventional filesystem on them You might want to do RAW reads, so why do you put filesystem into this context? - something that does basic checks (range, possibility of operation) and submits operations to correct parent (blockctrl, MMC controller, whatnot). Ascii art might help here greatly (how these pieces fall together). I think I do understand it though. current code user - FS - offset calculation from partition info - drivers/disk new code user - FS - blockdev - blockctrl (or USB or SD controller) So your blockctrl should do the USB/SD/whatever muxing. partition blockdev does all the offset calculation and range check that FSs do now, and then submits the operation to the parent blockdev, which in turn submits it to blockctrl (or an SD controller in case of a SD card, or USB controller in case of a USB flash) Make sure you document this in the next series. Pavel Herrmann Best regards, Marek Vasut ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
On Friday 21 of September 2012 17:34:27 Marek Vasut wrote: Dear Pavel Herrmann, [...] blockctrl = AHCI, PIIX... whichever chip you have between SATA and PCI (or generally disk-bus and board-bus) So this is for sata ? Or will it also by used for SD/USB flash discs? no, blockctrl will be used for SATA, PATA, SCSI, and anything of the sort (device with several ports, block devices on said ports, ability to send read/write/query commands to devices on ports - definitely not USB, possibly also SD, but you probably want more operations from SD) Why not USB flash ? Why not SD, what other stuff do you need for that? Is the API not misdesigned then? you should have a blockdev driver for USB flash and SD, but not blockctrl blockdev = disk, partition, SD card Uh, let's say I understand (even if I don't see the correlation between partition and SD card) they are an ordered bunch of blocks with a conventional filesystem on them You might want to do RAW reads, so why do you put filesystem into this context? yes, you can do raw reads, but in most cases you are using a filesystem. i put filesystem there to differentiate from nand devices (which have a special flash- based filesystems in most cases). - something that does basic checks (range, possibility of operation) and submits operations to correct parent (blockctrl, MMC controller, whatnot). Ascii art might help here greatly (how these pieces fall together). I think I do understand it though. current code user - FS - offset calculation from partition info - drivers/disk new code user - FS - blockdev - blockctrl (or USB or SD controller) So your blockctrl should do the USB/SD/whatever muxing. no, blockdev shoud be the last common part, for SD/USB, you should have a different blockdev driver, that uses USB/SD API for the actual works blockctrl is just an unified look at whatever now resides in drivers/block partition blockdev does all the offset calculation and range check that FSs do now, and then submits the operation to the parent blockdev, which in turn submits it to blockctrl (or an SD controller in case of a SD card, or USB controller in case of a USB flash) Make sure you document this in the next series. Pavel Herrmann Best regards, Marek Vasut ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
Dear Pavel Herrmann, On Friday 21 of September 2012 17:34:27 Marek Vasut wrote: Dear Pavel Herrmann, [...] blockctrl = AHCI, PIIX... whichever chip you have between SATA and PCI (or generally disk-bus and board-bus) So this is for sata ? Or will it also by used for SD/USB flash discs? no, blockctrl will be used for SATA, PATA, SCSI, and anything of the sort (device with several ports, block devices on said ports, ability to send read/write/query commands to devices on ports - definitely not USB, possibly also SD, but you probably want more operations from SD) Why not USB flash ? Why not SD, what other stuff do you need for that? Is the API not misdesigned then? you should have a blockdev driver for USB flash and SD, but not blockctrl I'm lost again. Do I also need a blockdev driver for SATA controller now that I need a blockdev driver for SD card controller ? blockdev = disk, partition, SD card Uh, let's say I understand (even if I don't see the correlation between partition and SD card) they are an ordered bunch of blocks with a conventional filesystem on them You might want to do RAW reads, so why do you put filesystem into this context? yes, you can do raw reads, but in most cases you are using a filesystem. Not true, see how env is stored to these media. i put filesystem there to differentiate from nand devices (which have a special flash- based filesystems in most cases). Not true, raw IO on flash media is often used too. - something that does basic checks (range, possibility of operation) and submits operations to correct parent (blockctrl, MMC controller, whatnot). Ascii art might help here greatly (how these pieces fall together). I think I do understand it though. current code user - FS - offset calculation from partition info - drivers/disk new code user - FS - blockdev - blockctrl (or USB or SD controller) So your blockctrl should do the USB/SD/whatever muxing. no, blockdev shoud be the last common part, for SD/USB, you should have a different blockdev driver, that uses USB/SD API for the actual works blockctrl is just an unified look at whatever now resides in drivers/block Answer my question, you are contradicting yourself in your answer. So again, does blockctrl do the muxing between the downstream drivers (SD blockdev, USB blockdev, SATA blockdev, IDE blockdev ... ) ? partition blockdev does all the offset calculation and range check that FSs do now, and then submits the operation to the parent blockdev, which in turn submits it to blockctrl (or an SD controller in case of a SD card, or USB controller in case of a USB flash) Make sure you document this in the next series. Pavel Herrmann Best regards, Marek Vasut Best regards, Marek Vasut ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
On Friday 21 of September 2012 17:55:10 Marek Vasut wrote: Dear Pavel Herrmann, On Friday 21 of September 2012 17:34:27 Marek Vasut wrote: Dear Pavel Herrmann, [...] blockctrl = AHCI, PIIX... whichever chip you have between SATA and PCI (or generally disk-bus and board-bus) So this is for sata ? Or will it also by used for SD/USB flash discs? no, blockctrl will be used for SATA, PATA, SCSI, and anything of the sort (device with several ports, block devices on said ports, ability to send read/write/query commands to devices on ports - definitely not USB, possibly also SD, but you probably want more operations from SD) Why not USB flash ? Why not SD, what other stuff do you need for that? Is the API not misdesigned then? you should have a blockdev driver for USB flash and SD, but not blockctrl I'm lost again. Do I also need a blockdev driver for SATA controller now that I need a blockdev driver for SD card controller ? you need a blockdev for a blockctrl (see [5/11]), and you need a blockctrl driver for your SATA controller you can either implement your SD as a blockctrl and use that blockdev, or implement a separate blockdev for your SD card (this is the original intention) I have not looked at current SD API, but i do recall seeing some non-memory SDIO cards (wifi for example, not sure u-boot supports this though), so i dont think SD should be implemented as a blockctrl blockdev = disk, partition, SD card Uh, let's say I understand (even if I don't see the correlation between partition and SD card) they are an ordered bunch of blocks with a conventional filesystem on them You might want to do RAW reads, so why do you put filesystem into this context? yes, you can do raw reads, but in most cases you are using a filesystem. Not true, see how env is stored to these media. i put filesystem there to differentiate from nand devices (which have a special flash- based filesystems in most cases). Not true, raw IO on flash media is often used too. - something that does basic checks (range, possibility of operation) and submits operations to correct parent (blockctrl, MMC controller, whatnot). Ascii art might help here greatly (how these pieces fall together). I think I do understand it though. current code user - FS - offset calculation from partition info - drivers/disk new code user - FS - blockdev - blockctrl (or USB or SD controller) So your blockctrl should do the USB/SD/whatever muxing. no, blockdev shoud be the last common part, for SD/USB, you should have a different blockdev driver, that uses USB/SD API for the actual works blockctrl is just an unified look at whatever now resides in drivers/block Answer my question, you are contradicting yourself in your answer. So again, does blockctrl do the muxing between the downstream drivers (SD blockdev, USB blockdev, SATA blockdev, IDE blockdev ... ) ? again, no blockctrl is a common API primarily for SATA/PATA/SCSI controllers, blockdev is an abstraction of any block device, therefore you should have a AHCI blockctrl, piix blockctrl, bfin blockctrl, sil3114 blockctrl (add anything from drivers/block) but a USB blockdev and SD blockdev. see the difference? the idea is that there would be no difference when working with SATA/PATA/SCSI (as the commands are almost the same currently), but working with USB drives and SD cards would be a little different (that is from their own separate commands, but not through the blockdev layer) Pavel Herrmann ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
Dear Pavel Herrmann, [...] you should have a blockdev driver for USB flash and SD, but not blockctrl I'm lost again. Do I also need a blockdev driver for SATA controller now that I need a blockdev driver for SD card controller ? you need a blockdev for a blockctrl (see [5/11]), and you need a blockctrl driver for your SATA controller So blockctrl == The controller driver? Viva abbrevs. Rename it to block_controller_driver . you can either implement your SD as a blockctrl and use that blockdev SD as in ... SD card or SD host controller ? Use what blockdev ? , or implement a separate blockdev for your SD card (this is the original intention) Ok, so the general abstration is to have a block_controller_driver (blockctrl in your parlance) for each and every driver in drivers/block _and_ which provides only basic read/write block for the downstream drivers (block_device) attached to it _and_ proxifies them for particular device type handlers? Now block_device (blockdev) is either a whole disc, partition, or subpartition. It exports read/write block operations, but to complete them, it uses upcalls into it's parent, yes? These upcalls stop at first block_controller_driver, correct? The user only ever uses the read/write block operations of the block_device, yes? I have not looked at current SD API, but i do recall seeing some non-memory SDIO cards (wifi for example, not sure u-boot supports this though), so i dont think SD should be implemented as a blockctrl They are not. But you should have looked at them since if you don't, that means you ignored fundamental part of the block interface. But anyway, in case of SD card, the upcalls stop at block_controller_driver, which handles the block IO the specific SD controller way? blockdev = disk, partition, SD card Uh, let's say I understand (even if I don't see the correlation between partition and SD card) they are an ordered bunch of blocks with a conventional filesystem on them You might want to do RAW reads, so why do you put filesystem into this context? yes, you can do raw reads, but in most cases you are using a filesystem. Not true, see how env is stored to these media. i put filesystem there to differentiate from nand devices (which have a special flash- based filesystems in most cases). Not true, raw IO on flash media is often used too. - something that does basic checks (range, possibility of operation) and submits operations to correct parent (blockctrl, MMC controller, whatnot). Ascii art might help here greatly (how these pieces fall together). I think I do understand it though. current code user - FS - offset calculation from partition info - drivers/disk new code user - FS - blockdev - blockctrl (or USB or SD controller) So your blockctrl should do the USB/SD/whatever muxing. no, blockdev shoud be the last common part, for SD/USB, you should have a different blockdev driver, that uses USB/SD API for the actual works blockctrl is just an unified look at whatever now resides in drivers/block Answer my question, you are contradicting yourself in your answer. So again, does blockctrl do the muxing between the downstream drivers (SD blockdev, USB blockdev, SATA blockdev, IDE blockdev ... ) ? again, no blockctrl is a common API primarily for SATA/PATA/SCSI controllers, blockdev is an abstraction of any block device, therefore you should have a AHCI blockctrl, piix blockctrl, bfin blockctrl, sil3114 blockctrl (add anything from drivers/block) but a USB blockdev and SD blockdev. see the difference? I assume I do, confirm above. the idea is that there would be no difference when working with SATA/PATA/SCSI (as the commands are almost the same currently), but working with USB drives and SD cards would be a little different (that is from their own separate commands, but not through the blockdev layer) I see Pavel Herrmann Best regards, Marek Vasut ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
On Friday 21 of September 2012 20:00:10 Marek Vasut wrote: Dear Pavel Herrmann, [...] you should have a blockdev driver for USB flash and SD, but not blockctrl I'm lost again. Do I also need a blockdev driver for SATA controller now that I need a blockdev driver for SD card controller ? you need a blockdev for a blockctrl (see [5/11]), and you need a blockctrl driver for your SATA controller So blockctrl == The controller driver? Viva abbrevs. Rename it to block_controller_driver . thats far too long, dont you think? we only have 80 cols in code... you can either implement your SD as a blockctrl and use that blockdev SD as in ... SD card or SD host controller ? Use what blockdev ? either we say we only have SD memory (and will never ever have other SDIO cards), implement SD controller with blockctrl API (and change it slightly, because SD is inherently flash and therefore has an erase operation) on the other hand, we could have a separate API for SD controllers (richer than the blockctrl, to eventually suport non-memory SD cards), and then have a device that provides blockdev API on one end, and uses this SD API on the other (much like blockdev_ata in [5/11] does for blockctrl API). this is the original idea; for this reason, blockdev API already has an erase operation, even though blockctrl does not support it. , or implement a separate blockdev for your SD card (this is the original intention) Ok, so the general abstration is to have a block_controller_driver (blockctrl in your parlance) for each and every driver in drivers/block yes _and_ which provides only basic read/write block for the downstream drivers (block_device) attached to it yes _and_ proxifies them for particular device type handlers? not sure what you mean there. what device type handlers? is that SATA/SCSI/PATA? that should disappear, only reason i have it in code is because i am wrapping old APIs into the new one. Now block_device (blockdev) is either a whole disc, partition, or subpartition. It exports read/write block operations, but to complete them, it uses upcalls into it's parent, yes? yes These upcalls stop at first block_controller_driver, correct? in case of a hard disk, yes. in case of a USB flash, it uses USB calls to its parent (USB hub or whatever) to complete the task at hand The user only ever uses the read/write block operations of the block_device, yes? yes I have not looked at current SD API, but i do recall seeing some non-memory SDIO cards (wifi for example, not sure u-boot supports this though), so i dont think SD should be implemented as a blockctrl They are not. But you should have looked at them since if you don't, that means you ignored fundamental part of the block interface. But anyway, in case of SD card, the upcalls stop at block_controller_driver, which handles the block IO the specific SD controller way? see above for the options. original idea is no, but it should be possible to implement it that way blockdev = disk, partition, SD card Uh, let's say I understand (even if I don't see the correlation between partition and SD card) they are an ordered bunch of blocks with a conventional filesystem on them You might want to do RAW reads, so why do you put filesystem into this context? yes, you can do raw reads, but in most cases you are using a filesystem. Not true, see how env is stored to these media. i put filesystem there to differentiate from nand devices (which have a special flash- based filesystems in most cases). Not true, raw IO on flash media is often used too. - something that does basic checks (range, possibility of operation) and submits operations to correct parent (blockctrl, MMC controller, whatnot). Ascii art might help here greatly (how these pieces fall together). I think I do understand it though. current code user - FS - offset calculation from partition info - drivers/disk new code user - FS - blockdev - blockctrl (or USB or SD controller) So your blockctrl should do the USB/SD/whatever muxing. no, blockdev shoud be the last common part, for SD/USB, you should have a different blockdev driver, that uses USB/SD API for the actual works blockctrl is just an unified look at whatever now resides in drivers/block Answer my question, you are contradicting yourself in your answer. So again, does blockctrl do the muxing between the downstream drivers (SD blockdev, USB blockdev, SATA blockdev, IDE blockdev ... ) ? again, no blockctrl is a common API primarily for SATA/PATA/SCSI controllers, blockdev is an abstraction of any block device, therefore you should have a AHCI blockctrl, piix blockctrl, bfin
Re: [U-Boot] [PATCH 01/11] DM: add block device core
Dear Pavel Herrmann, On Friday 21 of September 2012 20:00:10 Marek Vasut wrote: Dear Pavel Herrmann, [...] you should have a blockdev driver for USB flash and SD, but not blockctrl I'm lost again. Do I also need a blockdev driver for SATA controller now that I need a blockdev driver for SD card controller ? you need a blockdev for a blockctrl (see [5/11]), and you need a blockctrl driver for your SATA controller So blockctrl == The controller driver? Viva abbrevs. Rename it to block_controller_driver . thats far too long, dont you think? we only have 80 cols in code... So what? You can abbrev. the variable name, so it won't get in the way. As you can see, I was confused by the name, do you expect others not to be? you can either implement your SD as a blockctrl and use that blockdev SD as in ... SD card or SD host controller ? Use what blockdev ? either we say we only have SD memory (and will never ever have other SDIO cards), implement SD controller with blockctrl API (and change it slightly, because SD is inherently flash and therefore has an erase operation) on the other hand, we could have a separate API for SD controllers (richer than the blockctrl, to eventually suport non-memory SD cards), and then have a device that provides blockdev API on one end, and uses this SD API on the other (much like blockdev_ata in [5/11] does for blockctrl API). this is the original idea; for this reason, blockdev API already has an erase operation, even though blockctrl does not support it. , or implement a separate blockdev for your SD card (this is the original intention) Ok, so the general abstration is to have a block_controller_driver (blockctrl in your parlance) for each and every driver in drivers/block yes _and_ which provides only basic read/write block for the downstream drivers (block_device) attached to it yes _and_ proxifies them for particular device type handlers? not sure what you mean there. what device type handlers? is that SATA/SCSI/PATA? that should disappear, only reason i have it in code is because i am wrapping old APIs into the new one. I mean the particular block_controller_driver instance routes the read/write block request from downstream block_device through SATA/SD/SCSI/whatever library or layer back into itself. But the later itself is the implementation of the library or layer API. Once the library call returns, the read/write block operation is complete and the result can be passed back to the downstream block_device. Yes? Now block_device (blockdev) is either a whole disc, partition, or subpartition. It exports read/write block operations, but to complete them, it uses upcalls into it's parent, yes? yes These upcalls stop at first block_controller_driver, correct? in case of a hard disk, yes. in case of a USB flash, it uses USB calls to its parent (USB hub or whatever) to complete the task at hand Let me reformulate -- there is only single block_controller_driver instance the request crosses on it's way up the driver tree. Yes? [...] Best regards, Marek Vasut ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
On Friday 21 of September 2012 21:17:43 Marek Vasut wrote: Dear Pavel Herrmann, On Friday 21 of September 2012 20:00:10 Marek Vasut wrote: Dear Pavel Herrmann, [...] you should have a blockdev driver for USB flash and SD, but not blockctrl I'm lost again. Do I also need a blockdev driver for SATA controller now that I need a blockdev driver for SD card controller ? you need a blockdev for a blockctrl (see [5/11]), and you need a blockctrl driver for your SATA controller So blockctrl == The controller driver? Viva abbrevs. Rename it to block_controller_driver . thats far too long, dont you think? we only have 80 cols in code... So what? You can abbrev. the variable name, so it won't get in the way. As you can see, I was confused by the name, do you expect others not to be? you can either implement your SD as a blockctrl and use that blockdev SD as in ... SD card or SD host controller ? Use what blockdev ? either we say we only have SD memory (and will never ever have other SDIO cards), implement SD controller with blockctrl API (and change it slightly, because SD is inherently flash and therefore has an erase operation) on the other hand, we could have a separate API for SD controllers (richer than the blockctrl, to eventually suport non-memory SD cards), and then have a device that provides blockdev API on one end, and uses this SD API on the other (much like blockdev_ata in [5/11] does for blockctrl API). this is the original idea; for this reason, blockdev API already has an erase operation, even though blockctrl does not support it. , or implement a separate blockdev for your SD card (this is the original intention) Ok, so the general abstration is to have a block_controller_driver (blockctrl in your parlance) for each and every driver in drivers/block yes _and_ which provides only basic read/write block for the downstream drivers (block_device) attached to it yes _and_ proxifies them for particular device type handlers? not sure what you mean there. what device type handlers? is that SATA/SCSI/PATA? that should disappear, only reason i have it in code is because i am wrapping old APIs into the new one. I mean the particular block_controller_driver instance routes the read/write block request from downstream block_device through SATA/SD/SCSI/whatever library or layer back into itself. But the later itself is the implementation of the library or layer API. Once the library call returns, the read/write block operation is complete and the result can be passed back to the downstream block_device. Yes? in that case no, the block controller should directly take care of the call, without it being translated into some form it likes better for its particular interface. the translation is udes as a mechanism to support old code, but eventually there should be none, and the drivers should take a request from block_device and take care of it (probably by using memory-mapped access, or however you communicate with that chip). there might be a shared library for old IDE drivers though, as they are more like a shared code with driver (and board)-specific hooks. Now block_device (blockdev) is either a whole disc, partition, or subpartition. It exports read/write block operations, but to complete them, it uses upcalls into it's parent, yes? yes These upcalls stop at first block_controller_driver, correct? in case of a hard disk, yes. in case of a USB flash, it uses USB calls to its parent (USB hub or whatever) to complete the task at hand Let me reformulate -- there is only single block_controller_driver instance the request crosses on it's way up the driver tree. Yes? one or none - requests on USB flashes should not pass through block_controller_driver. every child of block_controller should be a block_device (not necessarily the other way around), so there is no way you pass more instances block_controller on your way up. ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
Dear Pavel Herrmann, [...] I mean the particular block_controller_driver instance routes the read/write block request from downstream block_device through SATA/SD/SCSI/whatever library or layer back into itself. But the later itself is the implementation of the library or layer API. Once the library call returns, the read/write block operation is complete and the result can be passed back to the downstream block_device. Yes? in that case no, the block controller should directly take care of the call, without it being translated into some form it likes better for its particular interface. This is entirely wrong. This would mean for example for SD drivers, to implement whole SD stack. the translation is udes as a mechanism to support old code, but eventually there should be none, and the drivers should take a request from block_device and take care of it (probably by using memory-mapped access, or however you communicate with that chip). there might be a shared library for old IDE drivers though, as they are more like a shared code with driver (and board)-specific hooks. Now block_device (blockdev) is either a whole disc, partition, or subpartition. It exports read/write block operations, but to complete them, it uses upcalls into it's parent, yes? yes These upcalls stop at first block_controller_driver, correct? in case of a hard disk, yes. in case of a USB flash, it uses USB calls to its parent (USB hub or whatever) to complete the task at hand Let me reformulate -- there is only single block_controller_driver instance the request crosses on it's way up the driver tree. Yes? one or none - requests on USB flashes should not pass through block_controller_driver. Uh, what do they pass into then ? every child of block_controller should be a block_device (not necessarily the other way around I doubt it's even possible to be the other way around. ), so there is no way you pass more instances block_controller on your way up. Ok, let me explain again. Let's look at the USB case to make it more real-world- ish. Imagine you have a thumb drive with 2 partitions. Thus you have two instances of struct block_device [denote BDp] for the partitions and one more for the whole disc [denote BDd]. When you read from partition, you end up poking BDp, which pushes the request up into BDd. This in turn calls USB-flashdisc- block_controller_driver [call it UFc]. For flash disc to read data, it needs to do some USB transfers. These are provided by USB host controller [UHC]. Thus you need some glue between UHC and UFc ... this is what I'm talking about. Ok, I see the issue at hand. In case of a regular drive, this implements the IO directly. In case of SD, this is a proxy object which interfaces with some SD-library and prepares the SD commands and then pushes that up into the controller to do the job? Same thing for USB flashes ? Best regards, Marek Vasut ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
On Friday 21 of September 2012 23:11:57 Marek Vasut wrote: Dear Pavel Herrmann, [...] I mean the particular block_controller_driver instance routes the read/write block request from downstream block_device through SATA/SD/SCSI/whatever library or layer back into itself. But the later itself is the implementation of the library or layer API. Once the library call returns, the read/write block operation is complete and the result can be passed back to the downstream block_device. Yes? in that case no, the block controller should directly take care of the call, without it being translated into some form it likes better for its particular interface. This is entirely wrong. This would mean for example for SD drivers, to implement whole SD stack. no one is forbiding you from having a shared library of common routines, but you should not force anyone to use it. the translation is udes as a mechanism to support old code, but eventually there should be none, and the drivers should take a request from block_device and take care of it (probably by using memory-mapped access, or however you communicate with that chip). there might be a shared library for old IDE drivers though, as they are more like a shared code with driver (and board)-specific hooks. Now block_device (blockdev) is either a whole disc, partition, or subpartition. It exports read/write block operations, but to complete them, it uses upcalls into it's parent, yes? yes These upcalls stop at first block_controller_driver, correct? in case of a hard disk, yes. in case of a USB flash, it uses USB calls to its parent (USB hub or whatever) to complete the task at hand Let me reformulate -- there is only single block_controller_driver instance the request crosses on it's way up the driver tree. Yes? one or none - requests on USB flashes should not pass through block_controller_driver. Uh, what do they pass into then ? their parent (an USB hub) every child of block_controller should be a block_device (not necessarily the other way around I doubt it's even possible to be the other way around. ), so there is no way you pass more instances block_controller on your way up. Ok, let me explain again. Let's look at the USB case to make it more real-world- ish. Imagine you have a thumb drive with 2 partitions. Thus you have two instances of struct block_device [denote BDp] for the partitions and one more for the whole disc [denote BDd]. When you read from partition, you end up poking BDp, which pushes the request up into BDd. This in turn calls USB-flashdisc- block_controller_driver [call it UFc]. For flash disc to read data, it needs to do some USB transfers. These are provided by USB host controller [UHC]. Thus you need some glue between UHC and UFc ... this is what I'm talking about. there should be no UFc, your BDd driver should talk directly to your UHC (a driver that has blockdev API on one end, USB on the other) Ok, I see the issue at hand. In case of a regular drive, this implements the IO directly. In case of SD, this is a proxy object which interfaces with some SD-library and prepares the SD commands and then pushes that up into the controller to do the job? Same thing for USB flashes ? not every block device will have a block controller as a parent (or parent-of- parent in case of a partition). there would be a blockdev-usb that has a USB hub as a parent, and a blockdev-mmc, that has a mmc/sdio controller as a parent. so basically what you mean, without the block_controller in the middle - please note that the block_device API is actually richer than the block_controller API (has erase) for exactly this reason. Pavel Herrmann ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
Dear Pavel Herrmann, [...] one or none - requests on USB flashes should not pass through block_controller_driver. Uh, what do they pass into then ? their parent (an USB hub) block_device instance (aka. partition/disk) directly connected to USB hub instance does not seem right. every child of block_controller should be a block_device (not necessarily the other way around I doubt it's even possible to be the other way around. ), so there is no way you pass more instances block_controller on your way up. Ok, let me explain again. Let's look at the USB case to make it more real-world- ish. Imagine you have a thumb drive with 2 partitions. Thus you have two instances of struct block_device [denote BDp] for the partitions and one more for the whole disc [denote BDd]. When you read from partition, you end up poking BDp, which pushes the request up into BDd. This in turn calls USB-flashdisc- block_controller_driver [call it UFc]. For flash disc to read data, it needs to do some USB transfers. These are provided by USB host controller [UHC]. Thus you need some glue between UHC and UFc ... this is what I'm talking about. there should be no UFc, your BDd driver should talk directly to your UHC So my generic partition implementation (BDd) would have to implement USB flashdisc stuff, correct? This makes no sense. (a driver that has blockdev API on one end, USB on the other) Ok, so how would this work, every partition implementation implements upcalls for all USB, SCSI, SATA, IDE, SD, ... and gazilion other types of drive it can sit on? Ok, I see the issue at hand. In case of a regular drive, this implements the IO directly. In case of SD, this is a proxy object which interfaces with some SD-library and prepares the SD commands and then pushes that up into the controller to do the job? Same thing for USB flashes ? not every block device will have a block controller as a parent (or parent-of- parent in case of a partition). there would be a blockdev-usb that has a USB hub as a parent, and a blockdev-mmc, that has a mmc/sdio controller as a parent. So you would have a specific partition implementation for SD, SATA, IDE, SCSI, USB ... ? This is flawed. The partition should be a generic thing which knows nothing about where it's sitting at. So is the whole drive, same thing, it just has partitions hooked under it. I'd expect a block_controller to be the proxy object under which the block_device representing the disc is connected. And this block_controller to be proxifying the requests to the respective drivers (be it SD, SATA, whatever). so basically what you mean, without the block_controller in the middle - please note that the block_device API is actually richer than the block_controller API (has erase) for exactly this reason. Pavel Herrmann Best regards, Marek Vasut ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH 01/11] DM: add block device core
Dear Pavel Herrmann, This core will register all block devices (disk, cards, partitons) and provide unfied access to them, instead of current method with device + partition offset Signed-off-by: Pavel Herrmann morpheus.i...@gmail.com --- Makefile | 1 + drivers/blockdev/Makefile | 42 include/dm/blockdev.h | 121 ++ 3 files changed, 164 insertions(+) create mode 100644 drivers/blockdev/Makefile create mode 100644 include/dm/blockdev.h Why not use drivers/block/ ? [...] Best regards, Marek Vasut ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
