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authorRafal Kozik <rk@semihalf.com>2018-06-29 15:54:05 +0200
committerThomas Monjalon <thomas@monjalon.net>2018-06-30 00:12:58 +0200
commiteeffc9ef70a5c2f88a10233ecddb5ae2d2b5fd38 (patch)
tree7e82be57a97d9f2da3595b9e95b0b83351468235 /kernel
parent586e5e7cbffcef81a0c5b46361cdaba0988fe7e5 (diff)
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igb_uio: add write combining option
Write combining (WC) increases NIC performance by making better utilization of PCI bus, but cannot be use by all PMD. To get internal_addr memory need to be mapped. But as memory could not be mapped twice: with and without WC it should be skipped for WC. [1] To do not spoil other drivers that potentially could use internal_addr, parameter wc_activate adds possibility to skip it for those PMDs, that do not use it. [1] https://www.kernel.org/doc/ols/2008/ols2008v2-pages-135-144.pdf section 5.3 and 5.4 Signed-off-by: Rafal Kozik <rk@semihalf.com> Acked-by: Bruce Richardson <bruce.richardson@intel.com> Acked-by: Ferruh Yigit <ferruh.yigit@intel.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/linux/igb_uio/igb_uio.c20
1 files changed, 17 insertions, 3 deletions
diff --git a/kernel/linux/igb_uio/igb_uio.c b/kernel/linux/igb_uio/igb_uio.c
index b3233f1..3398eac 100644
--- a/kernel/linux/igb_uio/igb_uio.c
+++ b/kernel/linux/igb_uio/igb_uio.c
@@ -30,6 +30,7 @@ struct rte_uio_pci_dev {
int refcnt;
};
+static int wc_activate;
static char *intr_mode;
static enum rte_intr_mode igbuio_intr_mode_preferred = RTE_INTR_MODE_MSIX;
/* sriov sysfs */
@@ -375,9 +376,13 @@ igbuio_pci_setup_iomem(struct pci_dev *dev, struct uio_info *info,
len = pci_resource_len(dev, pci_bar);
if (addr == 0 || len == 0)
return -1;
- internal_addr = ioremap(addr, len);
- if (internal_addr == NULL)
- return -1;
+ if (wc_activate == 0) {
+ internal_addr = ioremap(addr, len);
+ if (internal_addr == NULL)
+ return -1;
+ } else {
+ internal_addr = NULL;
+ }
info->mem[n].name = name;
info->mem[n].addr = addr;
info->mem[n].internal_addr = internal_addr;
@@ -626,6 +631,9 @@ igbuio_pci_init_module(void)
return -EINVAL;
}
+ if (wc_activate != 0)
+ pr_info("wc_activate is set\n");
+
ret = igbuio_config_intr_mode(intr_mode);
if (ret < 0)
return ret;
@@ -650,6 +658,12 @@ MODULE_PARM_DESC(intr_mode,
" " RTE_INTR_MODE_LEGACY_NAME " Use Legacy interrupt\n"
"\n");
+module_param(wc_activate, int, 0);
+MODULE_PARM_DESC(wc_activate,
+"Activate support for write combining (WC) (default=0)\n"
+" 0 - disable\n"
+" other - enable\n");
+
MODULE_DESCRIPTION("UIO driver for Intel IGB PCI cards");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Intel Corporation");