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PCI: Add support for turning PCIe ECRC on or off

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Adds support for PCI Express transaction layer end-to-end CRC checking
(ECRC).  This patch will enable/disable ECRC checking by setting/clearing
the ECRC Check Enable and/or ECRC Generation Enable bits for devices that
support ECRC.

The ECRC setting is controlled by the "pci=ecrc=<policy>" command-line
option. If this option is not set or is set to 'bios", the enable and
generation bits are left in whatever state that firmware/BIOS set them to.
The "off" setting turns them off, and the "on" option turns them on (if the
device supports it).

Turning ECRC on or off can be a data integrity versus performance
tradeoff.  In theory, turning it on will catch more data errors, turning
it off means possibly better performance since CRC does not need to be
calculated by the PCIe hardware and packet sizes are reduced.

Signed-off-by: Andrew Patterson <andrew.patterson@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Andrew Patterson
2009-04-22 16:52:09 -06:00
committed by Jesse Barnes
parent f62795f1e8
commit 43c1640884
7 changed files with 174 additions and 7 deletions
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2
drivers/pci/pci.c
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@@ -2588,6 +2588,8 @@ static int __init pci_setup(char *str)
} else if (!strncmp(str, "resource_alignment=", 19)) {
pci_set_resource_alignment_param(str + 19,
strlen(str + 19));
} else if (!strncmp(str, "ecrc=", 5)) {
pcie_ecrc_get_policy(str + 5);
} else {
printk(KERN_ERR "PCI: Unknown option `%s'\n",
str);