Re: [PATCH] firewire: Enable remote DMA above 4 GB
On Jan 18 Stefan Richter wrote: > This makes all of a machine's memory accessible to remote debugging via > FireWire, using the physical response unit (i.e. RDMA) of OHCI-1394 link > layer controllers. > > This requires actual support by the controller. The only ones currently > known to support it are Agere/LSI FW643. Most if not all other OHCI-1394 > controllers do not implement the optional Physical Upper Bound register. > With them, RDMA will continue to be limited to the lowermost 4 GB. [...] PS, this patch does not switch remote DMA on. It only increases the range of remote access to all memory (instead of just 4 GB) _when_ remote DMA was switched on by other means. The latter is achieved by setting CONFIG_FIREWIRE_OHCI_REMOTE_DMA, or by a module parameter introduced by commit 8bc588e0e585 of linux1394.git, or if the physical DMA filter is opened through firewire-sbp2. -- Stefan Richter -=-- ---= =--=- http://arcgraph.de/sr/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] firewire: Enable remote DMA above 4 GB
This makes all of a machine's memory accessible to remote debugging via
FireWire, using the physical response unit (i.e. RDMA) of OHCI-1394 link
layer controllers.
This requires actual support by the controller. The only ones currently
known to support it are Agere/LSI FW643. Most if not all other OHCI-1394
controllers do not implement the optional Physical Upper Bound register.
With them, RDMA will continue to be limited to the lowermost 4 GB.
firewire-ohci's startup message in the kernel log is augmented to tell
whether the controller does expose more than 4 GB to RDMA.
While OHCI-1394 allows for a maximum Physical Upper Bound of
0x'' (near 256 TB), this implementation sets it to
0x8000'' (128 TB) in order to avoid interference with applications
that require interrupt-served asynchronous request reception at
respectively low addresses.
Derived from patch "firewire: Enable physical DMA above 4GB" by
Peter Hurley from March 27, 2013.
Signed-off-by: Stefan Richter
---
drivers/firewire/core-transaction.c |6 +++---
drivers/firewire/core.h |3 +++
drivers/firewire/ohci.c |8 +---
3 files changed, 11 insertions(+), 6 deletions(-)
--- a/drivers/firewire/core-transaction.c
+++ b/drivers/firewire/core-transaction.c
@@ -523,11 +523,11 @@ static DEFINE_SPINLOCK(address_handler_l
static LIST_HEAD(address_handler_list);
const struct fw_address_region fw_high_memory_region =
- { .start = 0x0001ULL, .end = 0xe000ULL, };
+ { .start = FW_MAX_PHYSICAL_RANGE, .end = 0xe000ULL, };
EXPORT_SYMBOL(fw_high_memory_region);
static const struct fw_address_region low_memory_region =
- { .start = 0xULL, .end = 0x0001ULL, };
+ { .start = 0xULL, .end = FW_MAX_PHYSICAL_RANGE, };
#if 0
const struct fw_address_region fw_private_region =
@@ -1217,7 +1217,7 @@ static void handle_low_memory(struct fw_
}
static struct fw_address_handler low_memory = {
- .length = 0x0001ULL,
+ .length = FW_MAX_PHYSICAL_RANGE,
.address_callback = handle_low_memory,
};
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -237,6 +237,9 @@ static inline bool is_next_generation(in
#define LOCAL_BUS 0xffc0
+/* arbitrarily chosen maximum range for physical DMA: 128 TB */
+#define FW_MAX_PHYSICAL_RANGE (128ULL << 40)
+
void fw_core_handle_request(struct fw_card *card, struct fw_packet *request);
void fw_core_handle_response(struct fw_card *card, struct fw_packet *packet);
int fw_get_response_length(struct fw_request *request);
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -2367,7 +2367,7 @@ static int ohci_enable(struct fw_card *c
reg_write(ohci, OHCI1394_FairnessControl, 0);
card->priority_budget_implemented = ohci->pri_req_max != 0;
- reg_write(ohci, OHCI1394_PhyUpperBound, 0x0001);
+ reg_write(ohci, OHCI1394_PhyUpperBound, FW_MAX_PHYSICAL_RANGE >> 16);
reg_write(ohci, OHCI1394_IntEventClear, ~0);
reg_write(ohci, OHCI1394_IntMaskClear, ~0);
@@ -3723,9 +3723,11 @@ static int pci_probe(struct pci_dev *dev
version = reg_read(ohci, OHCI1394_Version) & 0x00ff00ff;
ohci_notice(ohci,
"added OHCI v%x.%x device as card %d, "
- "%d IR + %d IT contexts, quirks 0x%x\n",
+ "%d IR + %d IT contexts, quirks 0x%x%s\n",
version >> 16, version & 0xff, ohci->card.index,
- ohci->n_ir, ohci->n_it, ohci->quirks);
+ ohci->n_ir, ohci->n_it, ohci->quirks,
+ reg_read(ohci, OHCI1394_PhyUpperBound) ?
+ ", >4 GB phys DMA" : "");
return 0;
--
Stefan Richter
-=-- ---= =--=-
http://arcgraph.de/sr/
--
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More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[PATCH] firewire: Enable remote DMA above 4 GB
This makes all of a machine's memory accessible to remote debugging via
FireWire, using the physical response unit (i.e. RDMA) of OHCI-1394 link
layer controllers.
This requires actual support by the controller. The only ones currently
known to support it are Agere/LSI FW643. Most if not all other OHCI-1394
controllers do not implement the optional Physical Upper Bound register.
With them, RDMA will continue to be limited to the lowermost 4 GB.
firewire-ohci's startup message in the kernel log is augmented to tell
whether the controller does expose more than 4 GB to RDMA.
While OHCI-1394 allows for a maximum Physical Upper Bound of
0x'' (near 256 TB), this implementation sets it to
0x8000'' (128 TB) in order to avoid interference with applications
that require interrupt-served asynchronous request reception at
respectively low addresses.
Derived from patch firewire: Enable physical DMA above 4GB by
Peter Hurley pe...@hurleysoftware.com from March 27, 2013.
Signed-off-by: Stefan Richter stef...@s5r6.in-berlin.de
---
drivers/firewire/core-transaction.c |6 +++---
drivers/firewire/core.h |3 +++
drivers/firewire/ohci.c |8 +---
3 files changed, 11 insertions(+), 6 deletions(-)
--- a/drivers/firewire/core-transaction.c
+++ b/drivers/firewire/core-transaction.c
@@ -523,11 +523,11 @@ static DEFINE_SPINLOCK(address_handler_l
static LIST_HEAD(address_handler_list);
const struct fw_address_region fw_high_memory_region =
- { .start = 0x0001ULL, .end = 0xe000ULL, };
+ { .start = FW_MAX_PHYSICAL_RANGE, .end = 0xe000ULL, };
EXPORT_SYMBOL(fw_high_memory_region);
static const struct fw_address_region low_memory_region =
- { .start = 0xULL, .end = 0x0001ULL, };
+ { .start = 0xULL, .end = FW_MAX_PHYSICAL_RANGE, };
#if 0
const struct fw_address_region fw_private_region =
@@ -1217,7 +1217,7 @@ static void handle_low_memory(struct fw_
}
static struct fw_address_handler low_memory = {
- .length = 0x0001ULL,
+ .length = FW_MAX_PHYSICAL_RANGE,
.address_callback = handle_low_memory,
};
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -237,6 +237,9 @@ static inline bool is_next_generation(in
#define LOCAL_BUS 0xffc0
+/* arbitrarily chosen maximum range for physical DMA: 128 TB */
+#define FW_MAX_PHYSICAL_RANGE (128ULL 40)
+
void fw_core_handle_request(struct fw_card *card, struct fw_packet *request);
void fw_core_handle_response(struct fw_card *card, struct fw_packet *packet);
int fw_get_response_length(struct fw_request *request);
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -2367,7 +2367,7 @@ static int ohci_enable(struct fw_card *c
reg_write(ohci, OHCI1394_FairnessControl, 0);
card-priority_budget_implemented = ohci-pri_req_max != 0;
- reg_write(ohci, OHCI1394_PhyUpperBound, 0x0001);
+ reg_write(ohci, OHCI1394_PhyUpperBound, FW_MAX_PHYSICAL_RANGE 16);
reg_write(ohci, OHCI1394_IntEventClear, ~0);
reg_write(ohci, OHCI1394_IntMaskClear, ~0);
@@ -3723,9 +3723,11 @@ static int pci_probe(struct pci_dev *dev
version = reg_read(ohci, OHCI1394_Version) 0x00ff00ff;
ohci_notice(ohci,
added OHCI v%x.%x device as card %d,
- %d IR + %d IT contexts, quirks 0x%x\n,
+ %d IR + %d IT contexts, quirks 0x%x%s\n,
version 16, version 0xff, ohci-card.index,
- ohci-n_ir, ohci-n_it, ohci-quirks);
+ ohci-n_ir, ohci-n_it, ohci-quirks,
+ reg_read(ohci, OHCI1394_PhyUpperBound) ?
+ , 4 GB phys DMA : );
return 0;
--
Stefan Richter
-=-- ---= =--=-
http://arcgraph.de/sr/
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] firewire: Enable remote DMA above 4 GB
On Jan 18 Stefan Richter wrote: This makes all of a machine's memory accessible to remote debugging via FireWire, using the physical response unit (i.e. RDMA) of OHCI-1394 link layer controllers. This requires actual support by the controller. The only ones currently known to support it are Agere/LSI FW643. Most if not all other OHCI-1394 controllers do not implement the optional Physical Upper Bound register. With them, RDMA will continue to be limited to the lowermost 4 GB. [...] PS, this patch does not switch remote DMA on. It only increases the range of remote access to all memory (instead of just 4 GB) _when_ remote DMA was switched on by other means. The latter is achieved by setting CONFIG_FIREWIRE_OHCI_REMOTE_DMA, or by a module parameter introduced by commit 8bc588e0e585 of linux1394.git, or if the physical DMA filter is opened through firewire-sbp2. -- Stefan Richter -=-- ---= =--=- http://arcgraph.de/sr/ -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
