[PATCH v2 0/3] Converting m68k WD33C93 drivers to DMA API

[PATCH v2 0/3] Converting m68k WD33C93 drivers to DMA API

[Michael Schmitz]

This series was precipitated by Arnd removing CONFIG_VIRT_TO_BUS. The
m68k WD33C93 still used virt_to_bus to convert virtual addresses to
physical addresses suitable for the DMA engines (note m68k does not
have an IOMMU and uses a direct mapping for DMA addresses). 

Arnd suggested to use dma_map_single() to set up dma mappings instead
of open-coding much the same in every driver dma_setup() function.

DMA setup on a3000 host adapters can be kept as-is (bounce
buffers are used only where the input buffer isn't cache line
aligned). Cache management is now taken care of by dma_map_single().
Note that I've restored bounce buffer allocation (dropped in v1) in
order to make minimal changes to the core logic.

On gvp11 and a2091 host adapters, only the lowest 16 MB of physical
memory can be directy addressed by DMA, and bounce buffers from that
space must be used (possibly allocated from chip RAM using the
custom allocator) if buffers are located in the higher memory regions.
No cache management is required for chip RAM bounce buffers.

The m68k VME mvme147 driver has no DMA addressing or alignment
restrictions and can be converted in the same way as the Amiga a3000
one, but will require conversion to a platform device driver first.

Only compile tested so far, and hardware testing might be hard to do.

Cheers,

   Michael

[PATCH v2 1/3] scsi - a3000.c: convert m68k WD33C93 drivers to DMA API

[Michael Schmitz]

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
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

--

Changes from v1:

- restore bounce buffer allocation (dropped in v1)

Arnd Bergmann:
- reorder dma mapping and bounce buffer copy
---
 drivers/scsi/a3000.c | 53 ++++++++++++++++++++++++++++++++++++--------
 1 file changed, 44 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/a3000.c b/drivers/scsi/a3000.c
index dd161885eed1..2c5cb1a02e86 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;
@@ -49,20 +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;
-- 
2.17.1

[PATCH v2 2/3] scsi - a2091.c: convert m68k WD33C93 drivers to DMA API

[Michael Schmitz]

Use dma_map_single() for a2091 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 mapping and bounce buffer copy
---
 drivers/scsi/a2091.c | 63 +++++++++++++++++++++++++++++++++-----------
 1 file changed, 48 insertions(+), 15 deletions(-)

diff --git a/drivers/scsi/a2091.c b/drivers/scsi/a2091.c
index cf703a1ecdda..74312400468b 100644
--- a/drivers/scsi/a2091.c
+++ b/drivers/scsi/a2091.c
@@ -24,8 +24,11 @@
 struct a2091_hostdata {
 	struct WD33C93_hostdata wh;
 	struct a2091_scsiregs *regs;
+	struct device *dev;
 };
 
+#define DMA_DIR(d)   ((d == DATA_OUT_DIR) ? DMA_TO_DEVICE : DMA_FROM_DEVICE)
+
 static irqreturn_t a2091_intr(int irq, void *data)
 {
 	struct Scsi_Host *instance = data;
@@ -45,15 +48,31 @@ static irqreturn_t a2091_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 a2091_hostdata *hdata = shost_priv(instance);
 	struct WD33C93_hostdata *wh = &hdata->wh;
 	struct a2091_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;
 
 	/* don't allow DMA if the physical address is bad */
 	if (addr & A2091_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;
 		wh->dma_bounce_buffer = kmalloc(wh->dma_bounce_len,
 						GFP_KERNEL);
@@ -64,8 +83,21 @@ static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
 			return 1;
 		}
 
-		/* get the physical address of the bounce buffer */
-		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);
+		}
+
+		/* 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;
+		}
 
 		/* the bounce buffer may not be in the first 16M of physmem */
 		if (addr & A2091_XFER_MASK) {
@@ -76,11 +108,7 @@ static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
 			return 1;
 		}
 
-		if (!dir_in) {
-			/* copy to bounce buffer for a write */
-			memcpy(wh->dma_bounce_buffer, scsi_pointer->ptr,
-			       scsi_pointer->this_residual);
-		}
+		scsi_pointer->dma_handle = addr;
 	}
 
 	/* setup dma direction */
@@ -95,13 +123,8 @@ 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 */
 	regs->ST_DMA = 1;
 
@@ -142,6 +165,10 @@ static void dma_stop(struct Scsi_Host *instance, struct scsi_cmnd *SCpnt,
 	/* restore the CONTROL bits (minus the direction flag) */
 	regs->CNTR = CNTR_PDMD | CNTR_INTEN;
 
+	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)
@@ -178,6 +205,11 @@ static int a2091_probe(struct zorro_dev *z, const struct zorro_device_id *ent)
 	wd33c93_regs wdregs;
 	struct a2091_hostdata *hdata;
 
+	if (dma_set_mask_and_coherent(&z->dev, DMA_BIT_MASK(24))) {
+		dev_warn(&z->dev, "cannot use 24 bit DMA\n");
+		return -ENODEV;
+	}
+
 	if (!request_mem_region(z->resource.start, 256, "wd33c93"))
 		return -EBUSY;
 
@@ -198,6 +230,7 @@ static int a2091_probe(struct zorro_dev *z, const struct zorro_device_id *ent)
 	wdregs.SCMD = &regs->SCMD;
 
 	hdata = shost_priv(instance);
+	hdata->dev = &z->dev;
 	hdata->wh.no_sync = 0xff;
 	hdata->wh.fast = 0;
 	hdata->wh.dma_mode = CTRL_DMA;
-- 
2.17.1

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

[Michael Schmitz]

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

Re: [PATCH v2 0/3] Converting m68k WD33C93 drivers to DMA API

[Martin K. Petersen]

Michael,

> This series was precipitated by Arnd removing CONFIG_VIRT_TO_BUS. The
> m68k WD33C93 still used virt_to_bus to convert virtual addresses to
> physical addresses suitable for the DMA engines (note m68k does not
> have an IOMMU and uses a direct mapping for DMA addresses). 

Applied to 5.20/scsi-staging, thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [PATCH v2 0/3] Converting m68k WD33C93 drivers to DMA API

[Michael Schmitz]

Martin,

Am 08.07.2022 um 09:01 schrieb Martin K. Petersen:
>
> Michael,
>
>> This series was precipitated by Arnd removing CONFIG_VIRT_TO_BUS. The
>> m68k WD33C93 still used virt_to_bus to convert virtual addresses to
>> physical addresses suitable for the DMA engines (note m68k does not
>> have an IOMMU and uses a direct mapping for DMA addresses).
>
> Applied to 5.20/scsi-staging, thanks!

Thanks - I'll have the mvme147_scsi conversion out for review shortly.

Cheers,

	Michael

Re: [PATCH v2 0/3] Converting m68k WD33C93 drivers to DMA API

[Martin K. Petersen]

On Thu, 30 Jun 2022 15:32:59 +1200, Michael Schmitz wrote:

> This series was precipitated by Arnd removing CONFIG_VIRT_TO_BUS. The
> m68k WD33C93 still used virt_to_bus to convert virtual addresses to
> physical addresses suitable for the DMA engines (note m68k does not
> have an IOMMU and uses a direct mapping for DMA addresses).
> 
> Arnd suggested to use dma_map_single() to set up dma mappings instead
> of open-coding much the same in every driver dma_setup() function.
> 
> [...]

Applied to 5.20/scsi-queue, thanks!

[1/3] scsi - a3000.c: convert m68k WD33C93 drivers to DMA API
      https://git.kernel.org/mkp/scsi/c/e214806d52b8
[2/3] scsi - a2091.c: convert m68k WD33C93 drivers to DMA API
      https://git.kernel.org/mkp/scsi/c/479accbbb839
[3/3] scsi - gvp11.c: convert m68k WD33C93 drivers to DMA API
      https://git.kernel.org/mkp/scsi/c/158da6bcae7a

-- 
Martin K. Petersen	Oracle Linux Engineering