Commit 5fd77cb3 authored Aug 14, 2017 by Qiuxu Zhuo Committed by Borislav Petkov Aug 19, 2017

EDAC, pnd2: Conditionally unhide/hide the P2SB PCI device to read BAR



On Deverton server, the P2SB PCI device (DEV:1F, FUN:1) is used by multiple
device drivers.

If it's hidden by some device driver (e.g. with the i801 I2C driver,
the commit

  94246930 ("i2c: i801: Create iTCO device on newer Intel PCHs")

unconditionally hid the P2SB PCI device wrongly) it will make the
pnd2_edac driver read out an invalid BAR value of 0xffffffff and then
fail on ioremap().

Therefore, store the presence state of P2SB PCI device before unhiding
it for reading BAR and restore the presence state after reading BAR.

Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: linux-i2c@vger.kernel.org
Link: http://lkml.kernel.org/r/20170814154845.21663-1-qiuxu.zhuo@intel.com


Signed-off-by: Borislav Petkov <bp@suse.de>

parent d84676a9

drivers/edac/pnd2_edac.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -236,12 +236,23 @@ static u64 get_sideband_reg_base_addr(void)
		{
		struct pci_dev *pdev;
		u32 hi, lo;
		u8 hidden;

		pdev = pci_get_device(PCI_VENDOR_ID_INTEL, 0x19dd, NULL);
		if (pdev) {
		/* Unhide the P2SB device, if it's hidden */
		pci_read_config_byte(pdev, 0xe1, &hidden);
		if (hidden)
		pci_write_config_byte(pdev, 0xe1, 0);

		pci_read_config_dword(pdev, 0x10, &lo);
		pci_read_config_dword(pdev, 0x14, &hi);
		lo &= 0xfffffff0;

		/* Hide the P2SB device, if it was hidden before */
		if (hidden)
		pci_write_config_byte(pdev, 0xe1, hidden);

		pci_dev_put(pdev);
		return (U64_LSHIFT(hi, 32) \| U64_LSHIFT(lo, 0));
		} else {

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