Commit e214806d authored by Michael Schmitz's avatar Michael Schmitz Committed by Martin K. Petersen
Browse files

scsi: a3000: Convert m68k WD33C93 drivers to DMA API 

Use dma_map_single() for a3000 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/20220630033302.3183-2-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:

- restore bounce buffer allocation (dropped in v1)

Arnd Bergmann:
- reorder dma mapping and bounce buffer copy
parent a2417db3

drivers/scsi/a3000.c

+44 −9
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/spinlock.h>

#include <linux/interrupt.h>

#include <linux/platform_device.h>

#include <linux/dma-mapping.h>

#include <linux/module.h>



#include <asm/page.h>
@@ -25,8 +26,11 @@ 
struct a3000_hostdata {

	struct WD33C93_hostdata wh;

	struct a3000_scsiregs *regs;

	struct device *dev;

};



#define DMA_DIR(d)   ((d == DATA_OUT_DIR) ? DMA_TO_DEVICE : DMA_FROM_DEVICE)



static irqreturn_t a3000_intr(int irq, void *data)

{

	struct Scsi_Host *instance = data;
@@ -49,20 +53,38 @@ static irqreturn_t a3000_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 a3000_hostdata *hdata = shost_priv(instance);

	struct WD33C93_hostdata *wh = &hdata->wh;

	struct a3000_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;



	/*

	 * if the physical address has the wrong alignment, or if

	 * physical address is bad, or if it is a write and at the

	 * end of a physical memory chunk, then allocate a bounce

	 * buffer

	 * MSch 20220629 - only wrong alignment tested - bounce

	 * buffer returned by kmalloc is guaranteed to be aligned

	 */

	if (addr & A3000_XFER_MASK) {

		WARN_ONCE(1, "Invalid alignment for DMA!");

		/* drop useless mapping */

		dma_unmap_single(hdata->dev, scsi_pointer->dma_handle,

				 scsi_pointer->this_residual,

				 DMA_DIR(dir_in));



		wh->dma_bounce_len = (scsi_pointer->this_residual + 511) & ~0x1ff;

		wh->dma_bounce_buffer = kmalloc(wh->dma_bounce_len,

						GFP_KERNEL);
@@ -70,6 +92,7 @@ static int dma_setup(struct scsi_cmnd *cmd, int dir_in) 
		/* can't allocate memory; use PIO */

		if (!wh->dma_bounce_buffer) {

			wh->dma_bounce_len = 0;

			scsi_pointer->dma_handle = (dma_addr_t) NULL;

			return 1;

		}
@@ -79,7 +102,15 @@ static int dma_setup(struct scsi_cmnd *cmd, int dir_in) 
			       scsi_pointer->this_residual);

		}



		addr = virt_to_bus(wh->dma_bounce_buffer);

		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;

	}



	/* setup dma direction */
@@ -94,13 +125,7 @@ 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 */

	mb();			/* make sure setup is completed */
@@ -151,6 +176,10 @@ static void dma_stop(struct Scsi_Host *instance, struct scsi_cmnd *SCpnt, 
	regs->CNTR = CNTR_PDMD | CNTR_INTEN;

	mb();			/* make sure CNTR is updated before next IO */



	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 (SCpnt) {
@@ -193,6 +222,11 @@ static int __init amiga_a3000_scsi_probe(struct platform_device *pdev) 
	wd33c93_regs wdregs;

	struct a3000_hostdata *hdata;



	if (dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32))) {

		dev_warn(&pdev->dev, "cannot use 32 bit DMA\n");

		return -ENODEV;

	}



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (!res)

		return -ENODEV;
@@ -216,6 +250,7 @@ static int __init amiga_a3000_scsi_probe(struct platform_device *pdev) 
	wdregs.SCMD = &regs->SCMD;



	hdata = shost_priv(instance);

	hdata->dev = &pdev->dev;

	hdata->wh.no_sync = 0xff;

	hdata->wh.fast = 0;

	hdata->wh.dma_mode = CTRL_DMA;