From 6107e5cb907cffc5576cc1297847f9fc69a8d5d9 Mon Sep 17 00:00:00 2001 From: Heiner Kallweit Date: Fri, 20 Aug 2021 15:32:42 -0500 Subject: [PATCH] PCI/VPD: Add pci_vpd_check_csum() 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 Signed-off-by: Bjorn Helgaas --- drivers/pci/vpd.c | 23 +++++++++++++++++++++++ include/linux/pci.h | 9 +++++++++ 2 files changed, 32 insertions(+) diff --git a/drivers/pci/vpd.c b/drivers/pci/vpd.c index b1d012900f1e..01e57594781e 100644 --- a/drivers/pci/vpd.c +++ b/drivers/pci/vpd.c @@ -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 diff --git a/include/linux/pci.h b/include/linux/pci.h index 9e3b60963a52..827b7eefd550 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -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; -- 2.25.1