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scsi: a2091: Convert m68k WD33C93 drivers to DMA API

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Use dma_map_single() for a2091 driver (leave bounce buffer logic
unchanged).

Use dma_set_mask_and_coherent() to avoid explicit cache flushes.

Compile-tested only.

CC: linux-scsi@vger.kernel.org
Link: https://lore.kernel.org/r/6d1d88ee-1cf6-c735-1e6d-bafd2096e322@gmail.com
Link: https://lore.kernel.org/r/20220630033302.3183-3-schmitzmic@gmail.com
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

--

Changes from v1:

Arnd Bergmann:
- reorder mapping and bounce buffer copy
This commit is contained in:
Michael Schmitz 2022-06-30 15:33:01 +12:00 committed by Martin K. Petersen
parent e214806d52
commit 479accbbb8
1 changed files with 48 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

63
drivers/scsi/a2091.c
View File

@ -24,8 +24,11 @@
struct a2091_hostdata {
struct WD33C93_hostdata wh;
struct a2091_scsiregs *regs;
struct device *dev;
};
#define DMA_DIR(d) ((d == DATA_OUT_DIR) ? DMA_TO_DEVICE : DMA_FROM_DEVICE)
static irqreturn_t a2091_intr(int irq, void *data)
{
struct Scsi_Host *instance = data;
@ -45,15 +48,31 @@ static irqreturn_t a2091_intr(int irq, void *data)
static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
{
struct scsi_pointer *scsi_pointer = WD33C93_scsi_pointer(cmd);
unsigned long len = scsi_pointer->this_residual;
struct Scsi_Host *instance = cmd->device->host;
struct a2091_hostdata *hdata = shost_priv(instance);
struct WD33C93_hostdata *wh = &hdata->wh;
struct a2091_scsiregs *regs = hdata->regs;
unsigned short cntr = CNTR_PDMD | CNTR_INTEN;
unsigned long addr = virt_to_bus(scsi_pointer->ptr);
dma_addr_t addr;
addr = dma_map_single(hdata->dev, scsi_pointer->ptr,
len, DMA_DIR(dir_in));
if (dma_mapping_error(hdata->dev, addr)) {
dev_warn(hdata->dev, "cannot map SCSI data block %p\n",
scsi_pointer->ptr);
return 1;
}
scsi_pointer->dma_handle = addr;
/* don't allow DMA if the physical address is bad */
if (addr & A2091_XFER_MASK) {
/* drop useless mapping */
dma_unmap_single(hdata->dev, scsi_pointer->dma_handle,
scsi_pointer->this_residual,
DMA_DIR(dir_in));
scsi_pointer->dma_handle = (dma_addr_t) NULL;
wh->dma_bounce_len = (scsi_pointer->this_residual + 511) & ~0x1ff;
wh->dma_bounce_buffer = kmalloc(wh->dma_bounce_len,
GFP_KERNEL);
@ -64,8 +83,21 @@ static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
return 1;
}
/* get the physical address of the bounce buffer */
addr = virt_to_bus(wh->dma_bounce_buffer);
if (!dir_in) {
/* copy to bounce buffer for a write */
memcpy(wh->dma_bounce_buffer, scsi_pointer->ptr,
scsi_pointer->this_residual);
}
/* will flush/invalidate cache for us */
addr = dma_map_single(hdata->dev, wh->dma_bounce_buffer,
wh->dma_bounce_len, DMA_DIR(dir_in));
/* can't map buffer; use PIO */
if (dma_mapping_error(hdata->dev, addr)) {
dev_warn(hdata->dev, "cannot map bounce buffer %p\n",
wh->dma_bounce_buffer);
return 1;
}
/* the bounce buffer may not be in the first 16M of physmem */
if (addr & A2091_XFER_MASK) {
@ -76,11 +108,7 @@ static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
return 1;
}
if (!dir_in) {
/* copy to bounce buffer for a write */
memcpy(wh->dma_bounce_buffer, scsi_pointer->ptr,
scsi_pointer->this_residual);
}
scsi_pointer->dma_handle = addr;
}
/* setup dma direction */
@ -95,13 +123,8 @@ static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
/* setup DMA *physical* address */
regs->ACR = addr;
if (dir_in) {
/* invalidate any cache */
cache_clear(addr, scsi_pointer->this_residual);
} else {
/* push any dirty cache */
cache_push(addr, scsi_pointer->this_residual);
}
/* no more cache flush here - dma_map_single() takes care */
/* start DMA */
regs->ST_DMA = 1;
@ -142,6 +165,10 @@ static void dma_stop(struct Scsi_Host *instance, struct scsi_cmnd *SCpnt,
/* restore the CONTROL bits (minus the direction flag) */
regs->CNTR = CNTR_PDMD | CNTR_INTEN;
dma_unmap_single(hdata->dev, scsi_pointer->dma_handle,
scsi_pointer->this_residual,
DMA_DIR(wh->dma_dir));
/* copy from a bounce buffer, if necessary */
if (status && wh->dma_bounce_buffer) {
if (wh->dma_dir)
@ -178,6 +205,11 @@ static int a2091_probe(struct zorro_dev *z, const struct zorro_device_id *ent)
wd33c93_regs wdregs;
struct a2091_hostdata *hdata;
if (dma_set_mask_and_coherent(&z->dev, DMA_BIT_MASK(24))) {
dev_warn(&z->dev, "cannot use 24 bit DMA\n");
return -ENODEV;
}
if (!request_mem_region(z->resource.start, 256, "wd33c93"))
return -EBUSY;
@ -198,6 +230,7 @@ static int a2091_probe(struct zorro_dev *z, const struct zorro_device_id *ent)
wdregs.SCMD = &regs->SCMD;
hdata = shost_priv(instance);
hdata->dev = &z->dev;
hdata->wh.no_sync = 0xff;
hdata->wh.fast = 0;
hdata->wh.dma_mode = CTRL_DMA;