On 20.07.2012 13:56, Jassi Brar wrote:
On 20 July 2012 17:00, Dirk Behme <[email protected]> wrote:
On 19.07.2012 22:45, Jassi Brar wrote:
This problem can occur on many devices with embedded MMC and removable
SD,
e.g. smart phones. So I think we should find an solution to define MMC
scan
order or device number/name in a device tree.
I assume your issue is that due to async nature of mmc scanning, the
eMMC is detected later than external card, despite being the probe for
eMMC's slot initiated first ?
If so, we can do by simply associating 'N' of 'mmcblkN' with the slot
index i.e, mmc_host.index (instead of mmc_blk_data.name_idx). Which is
always in the order of probe calling. And we don't need to modify, or
expect more of, DT for that.
Do you mean something like
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -1536,7 +1536,7 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct
mmc_card *card,
*/
snprintf(md->disk->disk_name, sizeof(md->disk->disk_name),
- "mmcblk%d%s", md->name_idx, subname ? subname : "");
+ "mmcblk%d%s", card->host->index, subname ? subname : "");
blk_queue_logical_block_size(md->queue.queue, 512);
set_capacity(md->disk, size);
?
Exactly!
It seems too trivial and default for the author to have missed it, so
I suspect I am overlooking something yet again. I would dig email
archives to know more about that naming convention before dare submit
a patch :)
What's about anything like this [1]?
Best regards
Dirk
[1]
---
drivers/mmc/card/Kconfig | 27 +++++++++++++++++++++++++++
drivers/mmc/card/block.c | 2 +-
include/linux/mmc/host.h | 7 +++++++
3 files changed, 35 insertions(+), 1 deletion(-)
Index: a/drivers/mmc/card/Kconfig
===================================================================
--- a/drivers/mmc/card/Kconfig
+++ b/drivers/mmc/card/Kconfig
@@ -50,6 +50,33 @@ config MMC_BLOCK_BOUNCE
If unsure, say Y here.
+config MMC_SLOTINDEX
+ bool "Use host index for enumerating mmxblkN"
+ depends on MMC_BLOCK
+ default n
+ help
+ On embedded devices, often there is a combination of
+ removable mmc devices (e.g. MMC/SD cards) and hard
+ wired ones (e.g. eMMC). Depending on the hardware
+ configuration, the 'mmcblkN' node might change if
+ the removable device is available or not at boot time.
+
+ E.g. if the removable device is attached at boot time,
+ it might become mmxblk0. And the hard wired one mmcblk1.
+ But if the removable device isn't there at boot time,
+ the hard wired one will become mmcblk0. This makes it
+ somehow difficult to hard code the root device to the
+ non-removable device and boot fast.
+
+ Enabling this option will simply associating 'N' of
+ 'mmcblkN' with the slot index instead of the dynamic
+ name index. The slot index is always the same, ensuring
+ that the non-removable mmc device is associated always
+ with the same mmcblkN. Independent of the availability of
+ the removable one.
+
+ If unsure, say N here.
+
config SDIO_UART
tristate "SDIO UART/GPS class support"
help
Index: a/drivers/mmc/card/block.c
===================================================================
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -1536,7 +1536,7 @@ static struct mmc_blk_data *mmc_blk_allo
*/
snprintf(md->disk->disk_name, sizeof(md->disk->disk_name),
- "mmcblk%d%s", md->name_idx, subname ? subname : "");
+ "mmcblk%d%s", NAMEIDX, subname ? subname : "");
blk_queue_logical_block_size(md->queue.queue, 512);
set_capacity(md->disk, size);
Index: a/include/linux/mmc/host.h
===================================================================
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -437,4 +437,11 @@ static inline unsigned int mmc_host_clk_
return host->ios.clock;
}
#endif
+
+#ifdef CONFIG_MMC_SLOTINDEX
+#define NAMEIDX (card->host->index)
+#else
+#define NAMEIDX (md->name_idx)
+#endif
+
#endif /* LINUX_MMC_HOST_H */
--
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