[PATCH v2 3/3] scsi - gvp11.c: convert m68k WD33C93 drivers to DMA API

Michael Schmitz
2022-06-30T03:33:27Z

Use dma_map_single() for gvp11 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
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

--

Changes from v1:

Arnd Bergmann:
- reorder bounce buffer copy and dma mapping
---
drivers/scsi/gvp11.c | 95 +++++++++++++++++++++++++++++++++++---------
1 file changed, 77 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/gvp11.c b/drivers/scsi/gvp11.c
index 2f6c56aabe1d..e8b7a09eb8c7 100644
--- a/drivers/scsi/gvp11.c
+++ b/drivers/scsi/gvp11.c
@@ -26,8 +26,12 @@
struct gvp11_hostdata {
struct WD33C93_hostdata wh;
struct gvp11_scsiregs *regs;
+ struct device *dev;
};

+#define DMA_DIR(d) ((d == DATA_OUT_DIR) ? DMA_TO_DEVICE : DMA_FROM_DEVICE)
+#define TO_DMA_MASK(m) ((~(m & 0xfffffff0))-1)
+
static irqreturn_t gvp11_intr(int irq, void *data)
{
struct Scsi_Host *instance = data;
@@ -54,17 +58,33 @@ void gvp11_setup(char *str, int *ints)
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 gvp11_hostdata *hdata = shost_priv(instance);
struct WD33C93_hostdata *wh = &hdata->wh;
struct gvp11_scsiregs *regs = hdata->regs;
unsigned short cntr = GVP11_DMAC_INT_ENABLE;
- unsigned long addr = virt_to_bus(scsi_pointer->ptr);
+ dma_addr_t addr;
int bank_mask;
static int scsi_alloc_out_of_range = 0;

+ 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;
+
/* use bounce buffer if the physical address is bad */
if (addr & wh->dma_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;

if (!scsi_alloc_out_of_range) {
@@ -87,10 +107,32 @@ static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
wh->dma_buffer_pool = BUF_CHIP_ALLOCED;
}

- /* check if the address of the bounce buffer is OK */
- 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);
+ }
+
+ if (wh->dma_buffer_pool == BUF_SCSI_ALLOCED) {
+ /* 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;
+ }
+ }

if (addr & wh->dma_xfer_mask) {
+ /* drop useless mapping */
+ dma_unmap_single(hdata->dev, scsi_pointer->dma_handle,
+ scsi_pointer->this_residual,
+ DMA_DIR(dir_in));
/* fall back to Chip RAM if address out of range */
if (wh->dma_buffer_pool == BUF_SCSI_ALLOCED) {
kfree(wh->dma_bounce_buffer);
@@ -108,15 +150,19 @@ static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
return 1;
}

- 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);
+ }
+ /* chip RAM can be mapped to phys. address directly */
+ addr = virt_to_phys(wh->dma_bounce_buffer);
+ /* no need to flush/invalidate cache */
wh->dma_buffer_pool = BUF_CHIP_ALLOCED;
}
+ /* finally, have OK mapping (punted for PIO else) */
+ scsi_pointer->dma_handle = addr;

- if (!dir_in) {
- /* copy to bounce buffer for a write */
- memcpy(wh->dma_bounce_buffer, scsi_pointer->ptr,
- scsi_pointer->this_residual);
- }
}

/* setup dma direction */
@@ -129,13 +175,7 @@ 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 */

bank_mask = (~wh->dma_xfer_mask >> 18) & 0x01c0;
if (bank_mask)
@@ -161,6 +201,11 @@ static void dma_stop(struct Scsi_Host *instance, struct scsi_cmnd *SCpnt,
/* remove write bit from CONTROL bits */
regs->CNTR = GVP11_DMAC_INT_ENABLE;

+ if (wh->dma_buffer_pool == BUF_SCSI_ALLOCED)
+ 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 && SCpnt)
@@ -287,6 +332,13 @@ static int gvp11_probe(struct zorro_dev *z, const struct zorro_device_id *ent)

default_dma_xfer_mask = ent->driver_data;

+ if (dma_set_mask_and_coherent(&z->dev,
+ TO_DMA_MASK(default_dma_xfer_mask))) {
+ dev_warn(&z->dev, "cannot use DMA mask %x\n",
+ TO_DMA_MASK(default_dma_xfer_mask));
+ return -ENODEV;
+ }
+
/*
* Rumors state that some GVP ram boards use the same product
* code as the SCSI controllers. Therefore if the board-size
@@ -327,9 +379,16 @@ static int gvp11_probe(struct zorro_dev *z, const struct zorro_device_id *ent)
wdregs.SCMD = &regs->SCMD;

hdata = shost_priv(instance);
- if (gvp11_xfer_mask)
+ if (gvp11_xfer_mask) {
hdata->wh.dma_xfer_mask = gvp11_xfer_mask;
- else
+ if (dma_set_mask_and_coherent(&z->dev,
+ TO_DMA_MASK(gvp11_xfer_mask))) {
+ dev_warn(&z->dev, "cannot use DMA mask %x\n",
+ TO_DMA_MASK(gvp11_xfer_mask));
+ error = -ENODEV;
+ goto fail_check_or_alloc;
+ }
+ } else
hdata->wh.dma_xfer_mask = default_dma_xfer_mask;

hdata->wh.no_sync = 0xff;
--
2.17.1