Re: AMD64 dma_alloc_coherent crashes on non PCI device (was SATA open bugs) II

[James Bottomley <James.Bottomley@SteelEye.com>]

On Fri, 2007-08-10 at 17:58 +0100, Alan Cox wrote:
> > Not in non platform code, please ... somewhere on the Janitor's list is
> > moving the dma_mask from the bus specific devices into the generic
> > device ... when that happens this quantity will become u64 and they
> > won't know what to do with the NULL check.
> 
> Ok filed for "kernel summit" 

Surely we don't need to wait until then?  This is the correct fix, isn't
it?  (Obviously I'll split it into a generic and a pcmcia specific piece
if it looks OK to everyone).

It sets the PCMCIA dma_mask up correctly and introduces a DMA_MASK_NONE
(I prefer that to DMA_0BIT_MASK but I can add that too if people want)
and gives Alan his is_device_dma_capable() API.

James

diff --git a/drivers/pcmcia/ds.c b/drivers/pcmcia/ds.c
index a996071..b3837d3 100644
--- a/drivers/pcmcia/ds.c
+++ b/drivers/pcmcia/ds.c
@@ -23,6 +23,7 @@
 #include <linux/crc32.h>
 #include <linux/firmware.h>
 #include <linux/kref.h>
+#include <linux/dma-mapping.h>
 
 #define IN_CARD_SERVICES
 #include <pcmcia/cs_types.h>
@@ -670,6 +671,9 @@ struct pcmcia_device * pcmcia_device_add(struct pcmcia_socket *s, unsigned int f
 	p_dev->dev.bus = &pcmcia_bus_type;
 	p_dev->dev.parent = s->dev.parent;
 	p_dev->dev.release = pcmcia_release_dev;
+	/* by default don't allow DMA */
+	p_dev->dma_mask = DMA_MASK_NONE;
+	p_dev->dev.dma_mask = &p_dev->dma_mask;
 	bus_id_len = sprintf (p_dev->dev.bus_id, "%d.%d", p_dev->socket->sock, p_dev->device_no);
 
 	p_dev->devname = kmalloc(6 + bus_id_len + 1, GFP_KERNEL);
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 2dc21cb..0ebfafb 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -24,6 +24,8 @@ enum dma_data_direction {
 #define DMA_28BIT_MASK	0x000000000fffffffULL
 #define DMA_24BIT_MASK	0x0000000000ffffffULL
 
+#define DMA_MASK_NONE	0x0ULL
+
 static inline int valid_dma_direction(int dma_direction)
 {
 	return ((dma_direction == DMA_BIDIRECTIONAL) ||
@@ -31,6 +33,11 @@ static inline int valid_dma_direction(int dma_direction)
 		(dma_direction == DMA_FROM_DEVICE));
 }
 
+static inline int is_device_dma_capable(struct device *dev)
+{
+	return dev->dma_mask != NULL && *dev->dma_mask != DMA_MASK_NONE;
+}
+
 #ifdef CONFIG_HAS_DMA
 #include <asm/dma-mapping.h>
 #else
diff --git a/include/pcmcia/ds.h b/include/pcmcia/ds.h
index 90ef552..f047a1f 100644
--- a/include/pcmcia/ds.h
+++ b/include/pcmcia/ds.h
@@ -184,6 +184,7 @@ struct pcmcia_device {
 
 	char *			prod_id[4];
 
+	u64			dma_mask;
 	struct device		dev;
 
 #ifdef CONFIG_PCMCIA_IOCTL