This patch really has two parts. Most of it adds a helper function that
does the
if(pci_dma_supported()) { ->dma_mask = mask }
code path. I was using the api today and didn't realize that I had to
set the mask myself, I assumed the _supported call would do it. If
people prefer the struct setting api, thats fine with me :)
It also seems goofy that pci_dma_supported() unconditionally return true
on x86. If a device needs a mask smaller than GFP_DMA (admitedly probably
won't exist in the real world, one hopes), they're going to have troubles
because x86 just falls back to GFP_DMA when the mask isn't 0xffffffff..
all totally untested, of course..
--
zach
--- linux-2.4.2/include/linux/pci.h.dmasup Wed Feb 28 10:26:14 2001
+++ linux-2.4.2/include/linux/pci.h Wed Feb 28 10:30:12 2001
@@ -527,6 +527,7 @@
int pci_enable_device(struct pci_dev *dev);
void pci_set_master(struct pci_dev *dev);
+int pci_set_dma_mask(struct pci_dev *dev, dma_addr_t mask);
int pci_set_power_state(struct pci_dev *dev, int state);
int pci_assign_resource(struct pci_dev *dev, int i);
--- linux-2.4.2/include/asm-i386/pci.h.dmasup Wed Feb 28 10:19:01 2001
+++ linux-2.4.2/include/asm-i386/pci.h Wed Feb 28 10:25:40 2001
@@ -152,6 +152,14 @@
*/
extern inline int pci_dma_supported(struct pci_dev *hwdev, dma_addr_t mask)
{
+ /*
+ * we fall back to GFP_DMA when the mask isn't all 1s,
+ * so we can't guarantee allocations that must be
+ * within a tighter range than GFP_DMA..
+ */
+ if(mask < 0x00ffffff)
+ return 0;
+
return 1;
}
--- linux-2.4.2/drivers/pci/pci.c.dmasup Wed Feb 28 10:26:34 2001
+++ linux-2.4.2/drivers/pci/pci.c Wed Feb 28 10:27:34 2001
@@ -518,6 +518,18 @@
pcibios_set_master(dev);
}
+int
+pci_set_dma_mask(struct pci_dev *dev, dma_addr_t mask)
+{
+ if(! pci_dma_supported(dev, mask))
+ return 0;
+
+ dev->dma_mask = mask;
+
+ return 1;
+}
+
+
/*
* Translate the low bits of the PCI base
* to the resource type
@@ -1206,6 +1218,7 @@
EXPORT_SYMBOL(pci_find_slot);
EXPORT_SYMBOL(pci_find_subsys);
EXPORT_SYMBOL(pci_set_master);
+EXPORT_SYMBOL(pci_set_dma_mask);
EXPORT_SYMBOL(pci_set_power_state);
EXPORT_SYMBOL(pci_assign_resource);
EXPORT_SYMBOL(pci_register_driver);
Zach Brown wrote:
> +int
> +pci_set_dma_mask(struct pci_dev *dev, dma_addr_t mask)
> +{
> + if(! pci_dma_supported(dev, mask))
> + return 0;
> +
> + dev->dma_mask = mask;
> +
> + return 1;
> +}
pci_dma_supported has a boolean return, but the kernel norm is to return
zero on success, and -EFOO on error. I like your proposal with the
extremely minor nit that I think pci_set_dma_mask should return ENODEV
or EIO or something on error, and zero on success.
Jeff
--
Jeff Garzik | "You see, in this world there's two kinds of
Building 1024 | people, my friend: Those with loaded guns
MandrakeSoft | and those who dig. You dig." --Blondie
> pci_dma_supported has a boolean return, but the kernel norm is to return
> zero on success, and -EFOO on error. I like your proposal with the
*nod* I just followed pci_dma_supported().
> extremely minor nit that I think pci_set_dma_mask should return ENODEV
> or EIO or something on error, and zero on success.
I agree, though I'd like to leave the decision up to people who live and
breathe this stuff.
please feel free to make minor adjustments and submit :)
- z
Zach Brown writes:
> > extremely minor nit that I think pci_set_dma_mask should return ENODEV
> > or EIO or something on error, and zero on success.
>
> I agree, though I'd like to leave the decision up to people who live and
> breathe this stuff.
>
> please feel free to make minor adjustments and submit :)
Jeff/Zach, I agree, I'm fully for such a patch, but please update the
documentation! It is the most important part of the patch.
Later,
David S. Miller
[email protected]
On Wed, Feb 28, 2001 at 03:23:53PM -0800, David S. Miller wrote:
> Jeff/Zach, I agree, I'm fully for such a patch, but please update the
> documentation! It is the most important part of the patch.
Very good point. I'll add Jeff's error returning and spin some minor
docs and resend.
thanks.