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accel/qaic: Implement quirk for SOC_HW_VERSION

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The SOC_HW_VERSION register in the BHI space is not correctly initialized
by the device and in many cases contains uninitialized data. The register
could contain 0xFFFFFFFF which is a special value to indicate a link
error in PCIe, therefore if observed, we could incorrectly think the
device is down.

Intercept reads for this register, and provide the correct value - every
production instance would read 0x60110200 if the device was operating as
intended.

Fixes: a36bf7af86 ("accel/qaic: Add MHI controller")
Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Pranjal Ramajor Asha Kanojiya <quic_pkanojiy@quicinc.com>
Reviewed-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231208163101.1295769-3-quic_jhugo@quicinc.com
This commit is contained in:
Jeffrey Hugo 2023-12-08 09:31:01 -07:00
parent c8b6f4ad2f
commit 4c8874c2a6
1 changed files with 14 additions and 1 deletions
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15
drivers/accel/qaic/mhi_controller.c
View file

@ -404,8 +404,21 @@ static struct mhi_controller_config aic100_config = {
static int mhi_read_reg(struct mhi_controller *mhi_cntrl, void __iomem *addr, u32 *out)
{
u32 tmp = readl_relaxed(addr);
u32 tmp;
/*
* SOC_HW_VERSION quirk
* The SOC_HW_VERSION register (offset 0x224) is not reliable and
* may contain uninitialized values, including 0xFFFFFFFF. This could
* cause a false positive link down error. Instead, intercept any
* reads and provide the correct value of the register.
*/
if (addr - mhi_cntrl->regs == 0x224) {
*out = 0x60110200;
return 0;
}
tmp = readl_relaxed(addr);
if (tmp == U32_MAX)
return -EIO;