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PCI/VPD: Add pci_vpd_check_csum()

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VPD checksum information and checksum calculation are specified by PCIe
r5.0, sec 6.28.2.2.  Therefore checksum handling can and should be moved
into the PCI VPD core.

Add pci_vpd_check_csum() to validate the VPD checksum.

[bhelgaas: split to separate patch]
Link: https://lore.kernel.org/r/1643bd7a-088e-1028-c9b0-9d112cf48d63@gmail.com
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Heiner Kallweit 2021-08-20 15:32:42 -05:00 committed by Bjorn Helgaas
parent 9e515c9f6c
commit 6107e5cb90
2 changed files with 32 additions and 0 deletions
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23
drivers/pci/vpd.c
View File

@ -413,6 +413,29 @@ int pci_vpd_find_ro_info_keyword(const void *buf, unsigned int len,
}
EXPORT_SYMBOL_GPL(pci_vpd_find_ro_info_keyword);
int pci_vpd_check_csum(const void *buf, unsigned int len)
{
const u8 *vpd = buf;
unsigned int size;
u8 csum = 0;
int rv_start;
rv_start = pci_vpd_find_ro_info_keyword(buf, len, PCI_VPD_RO_KEYWORD_CHKSUM, &size);
if (rv_start == -ENOENT) /* no checksum in VPD */
return 1;
else if (rv_start < 0)
return rv_start;
if (!size)
return -EINVAL;
while (rv_start >= 0)
csum += vpd[rv_start--];
return csum ? -EILSEQ : 0;
}
EXPORT_SYMBOL_GPL(pci_vpd_check_csum);
#ifdef CONFIG_PCI_QUIRKS
/*
* Quirk non-zero PCI functions to route VPD access through function 0 for

9
include/linux/pci.h
View File

@ -2376,6 +2376,15 @@ int pci_vpd_find_info_keyword(const u8 *buf, unsigned int off,
int pci_vpd_find_ro_info_keyword(const void *buf, unsigned int len,
const char *kw, unsigned int *size);
/**
* pci_vpd_check_csum - Check VPD checksum
* @buf: Pointer to buffered VPD data
* @len: VPD size
*
* Returns 1 if VPD has no checksum, otherwise 0 or an errno
*/
int pci_vpd_check_csum(const void *buf, unsigned int len);
/* PCI <-> OF binding helpers */
#ifdef CONFIG_OF
struct device_node;