On Sun, 24 Apr 2005, Guennadi Liakhovetski wrote:
> On Sat, 23 Apr 2005, James Bottomley wrote:
>
> > As long as the sg list hasn't gone through dma_map_sg, then you can rely
> > on its elements being contiguous in physical space. Once it's gone
> > through dma_map_sg, it's elements are contiguous in the bus space beyond
> > the IOMMU, so no longer (possibly) even physically contiguous.
>
> Thanks for the info. Let me see, if I got you right. Say, we've got an sg
> with 2 elements: first 2 * PAGE_SIZE long, offset 0, pointing to page #0,
> second PAGE_SIZE long, offset 0, page #3. Say, dma_map_sg returned 1, so,
> it mapped all those 3 (physically discontiguous) pages to a contiguous bus
> address range. And now sg_dma_len() returns 3 * PAGE_SIZE. But, I hope,
> the .page, .length, and .offset elements stayed unchanged, so, one can
> still walk elements 0 and 1, calculating a sum of sg[i].length and thus
> arrive to the required page, right?
>
> I'll redo the patch.
If my assumption above is right, the patch below should cover bigger than
page sg-elements too.
Thanks
Guennadi
---
Guennadi Liakhovetski
Clean up endianness conversions, don't use bus_to_virt(), map atomically
instead.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
diff -u a/drivers/scsi/tmscsim.c b/drivers/scsi/tmscsim.c
--- a/drivers/scsi/tmscsim.c 13 Jan 2005 21:10:01
+++ b/drivers/scsi/tmscsim.c 24 Apr 2005 12:59:36
@@ -856,8 +856,8 @@
pSRB->pSegmentList++;
psgl = pSRB->pSegmentList;
- pSRB->SGBusAddr = cpu_to_le32(pci_dma_lo32(sg_dma_address(psgl)));
- pSRB->SGToBeXferLen = cpu_to_le32(sg_dma_len(psgl));
+ pSRB->SGBusAddr = sg_dma_address(psgl);
+ pSRB->SGToBeXferLen = sg_dma_len(psgl);
}
else
pSRB->SGToBeXferLen = 0;
@@ -882,10 +882,48 @@
}
}
+
+/**
+ * dc390_kmap_atomic_sg - find and atomically map an sg-elemnt
+ * @sg: scatter-gather list
+ * @sg_count: number of segments in sg
+ * @offset: offset in bytes into sg, on return offset into the mapped area
+ * @len: on return number of bytes mapped
+ *
+ * Returns virtual address of the start of the mapped page
+ */
+static void *dc390_kmap_atomic_sg(struct scatterlist *sg, int sg_count, size_t *offset, size_t *len)
+{
+ int i;
+ size_t sg_len = 0;
+ struct page *page;
+
+ for (i = 0; i < sg_count; i++) {
+ sg_len += sg[i].length;
+ if (sg_len > *offset)
+ break;
+ }
+
+ BUG_ON(i == sg_count);
+
+ *len = sg_len - *offset;
+ *offset = sg[i].offset + sg[i].length - *len;
+
+ page = sg[i].page + (*offset >> PAGE_SHIFT);
+ *offset &= ~PAGE_MASK;
+
+ return kmap_atomic(page, KM_BIO_SRC_IRQ);
+}
+
+static void dc390_kunmap_atomic_sg(void *virt)
+{
+ kunmap_atomic(virt, KM_BIO_SRC_IRQ);
+}
+
static void
dc390_DataIn_0( struct dc390_acb* pACB, struct dc390_srb* pSRB, u8 *psstatus)
{
- u8 sstatus, residual, bval;
+ u8 sstatus;
struct scatterlist *psgl;
u32 ResidCnt, i;
unsigned long xferCnt;
@@ -931,16 +969,17 @@
pSRB->pSegmentList++;
psgl = pSRB->pSegmentList;
- pSRB->SGBusAddr = cpu_to_le32(pci_dma_lo32(sg_dma_address(psgl)));
- pSRB->SGToBeXferLen = cpu_to_le32(sg_dma_len(psgl));
+ pSRB->SGBusAddr = sg_dma_address(psgl);
+ pSRB->SGToBeXferLen = sg_dma_len(psgl);
}
else
pSRB->SGToBeXferLen = 0;
}
else /* phase changed */
{
- residual = 0;
- bval = DC390_read8 (Current_Fifo);
+ u8 residual = 0;
+ u8 bval = DC390_read8 (Current_Fifo);
+
while( bval & 0x1f )
{
DEBUG1(printk (KERN_DEBUG "Check for residuals,"));
@@ -988,10 +1027,25 @@
if( residual )
{
+ size_t count = 1;
+ unsigned long flags;
+ size_t offset = pSRB->TotalXferredLen;
+ struct scsi_cmnd *pcmd = pSRB->pcmd;
+ int sg_count = pcmd->use_sg ? : 1;
+ struct scatterlist *sg = pcmd->use_sg ?
+ (struct scatterlist *)pcmd->request_buffer : &pSRB->Segmentx;
+
bval = DC390_read8 (ScsiFifo); /* get one residual byte */
- ptr = (u8 *) bus_to_virt( pSRB->SGBusAddr );
- *ptr = bval;
- pSRB->SGBusAddr++; xferCnt++;
+
+ local_irq_save(flags);
+ ptr = (u8*)dc390_kmap_atomic_sg(sg, sg_count, &offset, &count);
+
+ *(ptr + offset) = bval;
+ dc390_kunmap_atomic_sg(ptr);
+ local_irq_restore(flags);
+
+ pSRB->SGBusAddr++;
+ xferCnt++;
pSRB->TotalXferredLen++;
pSRB->SGToBeXferLen--;
}
@@ -1212,32 +1266,31 @@
{
struct scsi_cmnd *pcmd = pSRB->pcmd;
struct scatterlist *psgl;
+
pSRB->TotalXferredLen = 0;
pSRB->SGIndex = 0;
if (pcmd->use_sg) {
+ unsigned long last_xfer;
+
pSRB->pSegmentList = (struct scatterlist *)pcmd->request_buffer;
- psgl = pSRB->pSegmentList;
- //dc390_pci_sync(pSRB);
- while (pSRB->TotalXferredLen + (unsigned long) sg_dma_len(psgl) < pSRB->Saved_Ptr)
- {
- pSRB->TotalXferredLen += (unsigned long) sg_dma_len(psgl);
- pSRB->SGIndex++;
- if( pSRB->SGIndex < pSRB->SGcount )
- {
- pSRB->pSegmentList++;
- psgl = pSRB->pSegmentList;
- pSRB->SGBusAddr = cpu_to_le32(pci_dma_lo32(sg_dma_address(psgl)));
- pSRB->SGToBeXferLen = cpu_to_le32(sg_dma_len(psgl));
- }
- else
- pSRB->SGToBeXferLen = 0;
+ for (psgl = pSRB->pSegmentList; pSRB->TotalXferredLen + sg_dma_len(psgl) < pSRB->Saved_Ptr; psgl++) {
+ pSRB->TotalXferredLen += sg_dma_len(psgl);
+ pSRB->SGIndex++;
}
- pSRB->SGToBeXferLen -= (pSRB->Saved_Ptr - pSRB->TotalXferredLen);
- pSRB->SGBusAddr += (pSRB->Saved_Ptr - pSRB->TotalXferredLen);
- printk (KERN_INFO "DC390: Pointer restored. Segment %i, Total %li, Bus %08lx\n",
- pSRB->SGIndex, pSRB->Saved_Ptr, pSRB->SGBusAddr);
+ BUG_ON(pSRB->SGIndex >= pSRB->SGcount);
+
+ last_xfer = pSRB->Saved_Ptr - pSRB->TotalXferredLen;
+
+ pSRB->pSegmentList += pSRB->SGIndex;
+ pSRB->SGBusAddr = sg_dma_address(psgl) + last_xfer;
+ pSRB->SGToBeXferLen = sg_dma_len(psgl) - last_xfer;
+
+ //dc390_pci_sync(pSRB);
+
+ DEBUG0(printk(KERN_INFO "DC390: Pointer restored. Segment %i, Total %li, Bus %08lx\n",
+ pSRB->SGIndex, pSRB->Saved_Ptr, pSRB->SGBusAddr));
} else if(pcmd->request_buffer) {
//dc390_pci_sync(pSRB);
@@ -1245,11 +1298,11 @@
pSRB->SGcount = 1;
pSRB->pSegmentList = (struct scatterlist *) &pSRB->Segmentx;
} else {
- pSRB->SGcount = 0;
- printk (KERN_INFO "DC390: RESTORE_PTR message for Transfer without Scatter-Gather ??\n");
+ pSRB->SGcount = 0;
+ printk (KERN_INFO "DC390: RESTORE_PTR message for Transfer without Scatter-Gather ??\n");
}
- pSRB->TotalXferredLen = pSRB->Saved_Ptr;
+ pSRB->TotalXferredLen = pSRB->Saved_Ptr;
}
@@ -1385,8 +1438,8 @@
if( !pSRB->SGToBeXferLen )
{
psgl = pSRB->pSegmentList;
- pSRB->SGBusAddr = cpu_to_le32(pci_dma_lo32(sg_dma_address(psgl)));
- pSRB->SGToBeXferLen = cpu_to_le32(sg_dma_len(psgl));
+ pSRB->SGBusAddr = sg_dma_address(psgl);
+ pSRB->SGToBeXferLen = sg_dma_len(psgl);
DEBUG1(printk (KERN_DEBUG " DC390: Next SG segment."));
}
lval = pSRB->SGToBeXferLen;
@@ -1397,8 +1450,8 @@
lval >>= 8;
DC390_write8 (CtcReg_High, (u8) lval);
- DC390_write32 (DMA_XferCnt, pSRB->SGToBeXferLen);
- DC390_write32 (DMA_XferAddr, pSRB->SGBusAddr);
+ DC390_write32 (DMA_XferCnt, cpu_to_le32(pSRB->SGToBeXferLen));
+ DC390_write32 (DMA_XferAddr, cpu_to_le32((u32)pSRB->SGBusAddr));
//DC390_write8 (DMA_Cmd, DMA_IDLE_CMD | ioDir); /* | DMA_INT; */
pSRB->SRBState = SRB_DATA_XFER;
@@ -2036,7 +2089,7 @@
if (pSRB)
{
- printk ("DC390: SRB: Xferred %08lx, Remain %08lx, State %08x, Phase %02x\n",
+ printk ("DC390: SRB: Xferred %08lx, Remain %08x, State %08x, Phase %02x\n",
pSRB->TotalXferredLen, pSRB->SGToBeXferLen, pSRB->SRBState,
pSRB->ScsiPhase);
printk ("DC390: AdpaterStatus: %02x, SRB Status %02x\n", pSRB->AdaptStatus, pSRB->SRBStatus);
-
: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
