ieee1394: sbp2: enforce s/g segment size limit
1. We don't need to round the SBP-2 segment size limit down to a
multiple of 4 kB (0xffff -> 0xf000). It is only necessary to
ensure quadlet alignment (0xffff -> 0xfffc).
2. Use dma_set_max_seg_size() to tell the DMA mapping infrastructure
and the block IO layer about the restriction. This way we can
remove the size checks and segment splitting in the queuecommand
path.
This assumes that no other code in the ieee1394 stack uses
dma_map_sg() with conflicting requirements. It furthermore assumes
that the controller device's platform actually allows us to set the
segment size to our liking. Assert the latter with a BUG_ON().
3. Also use blk_queue_max_segment_size() to tell the block IO layer
about it. It cannot know it because our scsi_add_host() does not
point to the FireWire controller's device.
We can also uniformly use dma_map_sg() for the single segment case just
like for the multi segment case, to further simplify the code.
Also clean up how the page table is converted to big endian.
Thanks to Grant Grundler and FUJITA Tomonori for advice.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/ieee1394/sbp2.h b/drivers/ieee1394/sbp2.h
index 875428b..c5036f1 100644
--- a/drivers/ieee1394/sbp2.h
+++ b/drivers/ieee1394/sbp2.h
@@ -139,13 +139,10 @@
u32 status_fifo_lo;
} __attribute__((packed));
-#define PAGE_TABLE_SET_SEGMENT_BASE_HI(v) ((v) & 0xffff)
-#define PAGE_TABLE_SET_SEGMENT_LENGTH(v) (((v) & 0xffff) << 16)
-
struct sbp2_unrestricted_page_table {
- u32 length_segment_base_hi;
- u32 segment_base_lo;
-} __attribute__((packed));
+ __be32 high;
+ __be32 low;
+};
#define RESP_STATUS_REQUEST_COMPLETE 0x0
#define RESP_STATUS_TRANSPORT_FAILURE 0x1
@@ -216,15 +213,18 @@
#define SBP2_UNIT_SPEC_ID_ENTRY 0x0000609e
#define SBP2_SW_VERSION_ENTRY 0x00010483
+/*
+ * The default maximum s/g segment size of a FireWire controller is
+ * usually 0x10000, but SBP-2 only allows 0xffff. Since buffers have to
+ * be quadlet-aligned, we set the length limit to 0xffff & ~3.
+ */
+#define SBP2_MAX_SEG_SIZE 0xfffc
/*
- * SCSI specific definitions
- */
-
-#define SBP2_MAX_SG_ELEMENT_LENGTH 0xf000
-/* There is no real limitation of the queue depth (i.e. length of the linked
+ * There is no real limitation of the queue depth (i.e. length of the linked
* list of command ORBs) at the target. The chosen depth is merely an
- * implementation detail of the sbp2 driver. */
+ * implementation detail of the sbp2 driver.
+ */
#define SBP2_MAX_CMDS 8
#define SBP2_SCSI_STATUS_GOOD 0x0
@@ -240,12 +240,6 @@
* Representations of commands and devices
*/
-enum sbp2_dma_types {
- CMD_DMA_NONE,
- CMD_DMA_PAGE,
- CMD_DMA_SINGLE
-};
-
/* Per SCSI command */
struct sbp2_command_info {
struct list_head list;
@@ -258,11 +252,6 @@
struct sbp2_unrestricted_page_table
scatter_gather_element[SG_ALL] __attribute__((aligned(8)));
dma_addr_t sge_dma;
- void *sge_buffer;
- dma_addr_t cmd_dma;
- enum sbp2_dma_types dma_type;
- unsigned long dma_size;
- enum dma_data_direction dma_dir;
};
/* Per FireWire host */