scsi: gvp11: Convert m68k WD33C93 drivers to DMA API

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
Link: https://lore.kernel.org/r/20220630033302.3183-4-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 bounce buffer copy and dma mapping

diff --git a/drivers/scsi/gvp11.c b/drivers/scsi/gvp11.c
index 2f6c56a..e8b7a09 100644 (file)
--- 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;