Commit 479accbb authored by Michael Schmitz's avatar Michael Schmitz Committed by Martin K. Petersen
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scsi: a2091: Convert m68k WD33C93 drivers to DMA API 

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: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarMichael Schmitz <schmitzmic@gmail.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>

--

Changes from v1:

Arnd Bergmann:
- reorder mapping and bounce buffer copy
parent e214806d

drivers/scsi/a2091.c

+48 −15
Original line number Diff line number Diff line
@@ -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;