[PATCH v2 5/5] scsi - convert mvme147.c driver to DMA API

Michael Schmitz
2022-07-12T07:58:54Z

Convert mvme147.c to DMA API to eliminate one of the last
usages of virt_to_bus().

CC: linux-scsi@vger.kernel.org
Link: https://lore.kernel.org/r/6d1d88ee-1cf6-c735-1e6d-bafd2096e322@gmail.com
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>

--

Changes from v1:
- change patch index from 3 to 4 (due to insertion of m68k kmap patch)
---
drivers/scsi/mvme147.c | 33 ++++++++++++++++++++++++---------
1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/mvme147.c b/drivers/scsi/mvme147.c
index ea8afeec8e56..166248bef6cf 100644
--- a/drivers/scsi/mvme147.c
+++ b/drivers/scsi/mvme147.c
@@ -21,6 +21,8 @@
#include "wd33c93.h"
#include "mvme147.h"

+#define DMA_DIR(d) ((d == DATA_OUT_DIR) ? DMA_TO_DEVICE : DMA_FROM_DEVICE)
+
static irqreturn_t mvme147_intr(int irq, void *data)
{
struct Scsi_Host *instance = data;
@@ -35,10 +37,20 @@ static irqreturn_t mvme147_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 WD33C93_hostdata *hdata = shost_priv(instance);
unsigned char flags = 0x01;
- unsigned long addr = virt_to_bus(scsi_pointer->ptr);
+ dma_addr_t addr;
+
+ addr = dma_map_single(instance->dma_dev, scsi_pointer->ptr,
+ len, DMA_DIR(dir_in));
+ if (dma_mapping_error(instance->dma_dev, addr)) {
+ dev_warn(instance->dma_dev, "cannot map SCSI data block %p\n",
+ scsi_pointer->ptr);
+ return 1;
+ }
+ scsi_pointer->dma_handle = addr;

/* setup dma direction */
if (!dir_in)
@@ -47,14 +59,6 @@ static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
/* remember direction */
hdata->dma_dir = dir_in;

- 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);
- }
-
/* start DMA */
m147_pcc->dma_bcr = scsi_pointer->this_residual | (1 << 24);
m147_pcc->dma_dadr = addr;
@@ -67,7 +71,13 @@ static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
static void dma_stop(struct Scsi_Host *instance, struct scsi_cmnd *SCpnt,
int status)
{
+ struct scsi_pointer *scsi_pointer = WD33C93_scsi_pointer(SCpnt);
+ struct WD33C93_hostdata *hdata = shost_priv(instance);
+
m147_pcc->dma_cntrl = 0;
+ dma_unmap_single(instance->dma_dev, scsi_pointer->dma_handle,
+ scsi_pointer->this_residual,
+ DMA_DIR(hdata->dma_dir));
}

static struct scsi_host_template mvme147_host_template = {
@@ -95,6 +105,11 @@ static int __init mvme147_scsi_probe(struct platform_device *pdev)
void __iomem *base;
int error = -ENOMEM;

+ if (dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32))) {
+ dev_warn(&pdev->dev, "cannot use 32 bit DMA\n");
+ return -ENODEV;
+ }
+
mres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mres)
return -ENODEV;
--
2.17.1