[PATCH] pci_set_dac helper
From: Jeff Garzik (jgarzik_at_pobox.com)
Date: 12/31/03
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- Reply: Matthew Wilcox: "Re: [PATCH] pci_set_dac helper"
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Date: Wed, 31 Dec 2003 11:12:42 -0500 To: Linux Kernel <linux-kernel@vger.kernel.org>
It seems to me like a lot of drivers wind up getting their
pci_set_dma_mask stuff wrong, occasionally in subtle ways. So, I
created a "give me 64-bit PCI DMA" helper function.
The attached patch demonstrates its use in tg3, from which the logic
originated. It also fixes a tiny bug in tg3, whereby it might return
zero on error (rather than -EFOO) if the pci_set_dma_mask succeeds but
pci_set_consistent_dma_mask fails.
===== drivers/net/tg3.c 1.112 vs edited =====
--- 1.112/drivers/net/tg3.c Thu Nov 20 12:46:05 2003
+++ edited/drivers/net/tg3.c Wed Dec 31 11:06:43 2003
@@ -7493,7 +7493,8 @@
unsigned long tg3reg_base, tg3reg_len;
struct net_device *dev;
struct tg3 *tp;
- int i, err, pci_using_dac, pm_cap;
+ int i, err, pm_cap;
+ u32 dac_flags;
if (tg3_version_printed++ == 0)
printk(KERN_INFO "%s", version);
@@ -7530,21 +7531,16 @@
}
/* Configure DMA attributes. */
- if (!pci_set_dma_mask(pdev, 0xffffffffffffffffULL)) {
- pci_using_dac = 1;
- if (pci_set_consistent_dma_mask(pdev, 0xffffffffffffffffULL)) {
- printk(KERN_ERR PFX "Unable to obtain 64 bit DMA "
- "for consistent allocations\n");
- goto err_out_free_res;
- }
- } else {
- err = pci_set_dma_mask(pdev, 0xffffffffULL);
- if (err) {
- printk(KERN_ERR PFX "No usable DMA configuration, "
- "aborting.\n");
- goto err_out_free_res;
- }
- pci_using_dac = 0;
+ dac_flags = 0;
+ err = pci_set_dac(pdev, &dac_flags);
+ if (err)
+ goto err_out_free_res;
+
+ if ((dac_flags & (PCI_DAC_EN | PCI_DAC_CONS_EN)) == PCI_DAC_EN) {
+ printk(KERN_ERR PFX "Unable to obtain 64 bit DMA "
+ "for consistent allocations\n");
+ err = -EIO;
+ goto err_out_free_res;
}
tg3reg_base = pci_resource_start(pdev, 0);
@@ -7560,7 +7556,7 @@
SET_MODULE_OWNER(dev);
SET_NETDEV_DEV(dev, &pdev->dev);
- if (pci_using_dac)
+ if (dac_flags)
dev->features |= NETIF_F_HIGHDMA;
#if TG3_VLAN_TAG_USED
dev->features |= NETIF_F_HW_VLAN_TX | NETIF_F_HW_VLAN_RX;
===== drivers/pci/pci.c 1.60 vs edited =====
--- 1.60/drivers/pci/pci.c Sun Oct 5 04:07:55 2003
+++ edited/drivers/pci/pci.c Wed Dec 31 11:00:44 2003
@@ -713,7 +713,32 @@
return 0;
}
-
+
+int
+pci_set_dac(struct pci_dev *dev, u32 *flags_out)
+{
+ int err = 0;
+ u32 flags = 0;
+
+ if (!pci_set_dma_mask(dev, 0xffffffffffffffffULL)) {
+ flags |= PCI_DAC_EN;
+ if (pci_set_consistent_dma_mask(dev, 0xffffffffffffffffULL))
+ printk(KERN_WARNING
+ "PCI(%s): Unable to obtain 64 bit DMA "
+ "for consistent allocations\n", pci_name(dev));
+ else
+ flags |= PCI_DAC_CONS_EN;
+ } else {
+ err = pci_set_dma_mask(dev, 0xffffffffULL);
+ if (err)
+ printk(KERN_ERR "PCI(%s): No usable DMA configuration",
+ pci_name(dev));
+ }
+
+ *flags_out = flags;
+ return err;
+}
+
static int __devinit pci_init(void)
{
struct pci_dev *dev = NULL;
@@ -765,6 +790,7 @@
EXPORT_SYMBOL(pci_clear_mwi);
EXPORT_SYMBOL(pci_set_dma_mask);
EXPORT_SYMBOL(pci_dac_set_dma_mask);
+EXPORT_SYMBOL(pci_set_dac);
EXPORT_SYMBOL(pci_set_consistent_dma_mask);
EXPORT_SYMBOL(pci_assign_resource);
EXPORT_SYMBOL(pci_find_parent_resource);
===== include/linux/pci.h 1.109 vs edited =====
--- 1.109/include/linux/pci.h Mon Dec 29 16:37:23 2003
+++ edited/include/linux/pci.h Wed Dec 31 10:54:16 2003
@@ -340,6 +340,10 @@
#define PCIIOC_MMAP_IS_MEM (PCIIOC_BASE | 0x02) /* Set mmap state to MEM space. */
#define PCIIOC_WRITE_COMBINE (PCIIOC_BASE | 0x03) /* Enable/disable write-combining. */
+/* pci_set_dac flags */
+#define PCI_DAC_EN (1 << 0)
+#define PCI_DAC_CONS_EN (1 << 1)
+
#ifdef __KERNEL__
#include <linux/types.h>
@@ -653,6 +657,8 @@
void pci_clear_mwi(struct pci_dev *dev);
int pci_set_dma_mask(struct pci_dev *dev, u64 mask);
int pci_dac_set_dma_mask(struct pci_dev *dev, u64 mask);
+int pci_set_dac(struct pci_dev *dev, u32 *flags);
+
int pci_set_consistent_dma_mask(struct pci_dev *dev, u64 mask);
int pci_assign_resource(struct pci_dev *dev, int i);
@@ -759,6 +765,8 @@
static inline int pci_module_init(struct pci_driver *drv) { return -ENODEV; }
static inline int pci_set_dma_mask(struct pci_dev *dev, u64 mask) { return -EIO; }
static inline int pci_dac_set_dma_mask(struct pci_dev *dev, u64 mask) { return -EIO; }
+static inline int pci_set_dac(struct pci_dev *dev, u32 *flags) { return -EIO; }
+
static inline int pci_assign_resource(struct pci_dev *dev, int i) { return -EBUSY;}
static inline int pci_register_driver(struct pci_driver *drv) { return 0;}
static inline void pci_unregister_driver(struct pci_driver *drv) { }
-
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- Previous message: Christophe Saout: "Re: question about BIO/request ordering / barriers"
- Next in thread: David S. Miller: "Re: [PATCH] pci_set_dac helper"
- Reply: David S. Miller: "Re: [PATCH] pci_set_dac helper"
- Reply: Matthew Wilcox: "Re: [PATCH] pci_set_dac helper"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
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