Use dma_map_single() for a3000 driver (leave bounce buffer logic unchanged). Use dma_set_mask_and_coherent() to avoid explicit cache flushes. Incorporates review comments by ArndB: - drop bounce buffer handling - non-cacheline aligned buffers ought not to happen. Compile-tested only. CC: linux-scsi@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/6d1d88ee-1cf6-c735-1e6d-bafd2096e322@xxxxxxxxx Signed-off-by: Michael Schmitz <schmitzmic@xxxxxxxxx> --- drivers/scsi/a3000.c | 60 ++++++++++++++++++++++++++------------------ 1 file changed, 35 insertions(+), 25 deletions(-) diff --git a/drivers/scsi/a3000.c b/drivers/scsi/a3000.c index dd161885eed1..0e2e0d69118b 100644 --- a/drivers/scsi/a3000.c +++ b/drivers/scsi/a3000.c @@ -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; @@ -49,37 +53,40 @@ 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, skip bounce + * buffer set-up and just do PIO here. Buffers not aligned + * to cachelines ought to not happen anymore. */ if (addr & A3000_XFER_MASK) { - wh->dma_bounce_len = (scsi_pointer->this_residual + 511) & ~0x1ff; - wh->dma_bounce_buffer = kmalloc(wh->dma_bounce_len, - GFP_KERNEL); - - /* can't allocate memory; use PIO */ - if (!wh->dma_bounce_buffer) { - wh->dma_bounce_len = 0; - return 1; - } - - if (!dir_in) { - /* copy to bounce buffer for a write */ - memcpy(wh->dma_bounce_buffer, scsi_pointer->ptr, - scsi_pointer->this_residual); - } - - addr = virt_to_bus(wh->dma_bounce_buffer); + 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)); + scsi_pointer->dma_handle = (dma_addr_t) NULL; + return 1; } /* setup dma direction */ @@ -94,13 +101,7 @@ 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 - coherent DMA setup used */ /* start DMA */ mb(); /* make sure setup is completed */ @@ -166,6 +167,9 @@ static void dma_stop(struct Scsi_Host *instance, struct scsi_cmnd *SCpnt, wh->dma_bounce_len = 0; } } + dma_unmap_single(hdata->dev, scsi_pointer->dma_handle, + scsi_pointer->this_residual, + DMA_DIR(wh->dma_dir)); } static struct scsi_host_template amiga_a3000_scsi_template = { @@ -193,6 +197,11 @@ 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 +225,7 @@ static int __init amiga_a3000_scsi_probe(struct platform_device *pdev) wdregs.SCMD = ®s->SCMD; hdata = shost_priv(instance); + hdata->dev = &pdev->dev; hdata->wh.no_sync = 0xff; hdata->wh.fast = 0; hdata->wh.dma_mode = CTRL_DMA; -- 2.17.1
