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authorMika Westerberg <mika.westerberg@linux.intel.com>2017-07-28 13:50:42 +0300
committerLee Jones <lee.jones@linaro.org>2017-09-05 08:46:01 +0100
commitd9018976cdb6eefc62a7ba79a405f6c9661b08a7 (patch)
tree2e7aa3e375a4cc7479fad103c38536f8c9f23aaf /drivers/mfd
parentb0f3ab20e76499db12b0bbadb5737d9870f10418 (diff)
downloadlinux-d9018976cdb6eefc62a7ba79a405f6c9661b08a7.tar.bz2
mfd: lpc_ich: Do not touch SPI-NOR write protection bit on Haswell/Broadwell
At least on Lenovo Thinkpad Yoga, the BIOS seems to monitor the SPI-NOR write protection bit and if it is flipped to read/write it assumes the BIOS configuration was changed on next reboot. It then, for unknown reasons, resets the BIOS settings back to default. We can prevent this by just leaving the write protection bit intact and let the SPI-NOR driver know whether the device is writable or not. In case of this particular Lenovo the SPI-NOR flash will be exposed as read-only. Fixes: ff00d7a32a1b ("mfd: lpc_ich: Add support for SPI serial flash host controller") Link: https://bugzilla.kernel.org/show_bug.cgi?id=195951 Reported-by: Abdó Roig-Marange <abdo.roig@gmail.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'drivers/mfd')
-rw-r--r--drivers/mfd/lpc_ich.c10
1 files changed, 0 insertions, 10 deletions
diff --git a/drivers/mfd/lpc_ich.c b/drivers/mfd/lpc_ich.c
index 773f1554d2f9..450ae36645aa 100644
--- a/drivers/mfd/lpc_ich.c
+++ b/drivers/mfd/lpc_ich.c
@@ -1119,17 +1119,7 @@ static int lpc_ich_init_spi(struct pci_dev *dev)
res->start = spi_base + SPIBASE_LPT;
res->end = res->start + SPIBASE_LPT_SZ - 1;
- /*
- * Try to make the flash chip writeable now by
- * setting BCR_WPD. It it fails we tell the driver
- * that it can only read the chip.
- */
pci_read_config_dword(dev, BCR, &bcr);
- if (!(bcr & BCR_WPD)) {
- bcr |= BCR_WPD;
- pci_write_config_dword(dev, BCR, bcr);
- pci_read_config_dword(dev, BCR, &bcr);
- }
info->writeable = !!(bcr & BCR_WPD);
}
break;