Commit 4c8874c2 authored by Jeff Hugo's avatar Jeff Hugo
Browse files

accel/qaic: Implement quirk for SOC_HW_VERSION 



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: a36bf7af ("accel/qaic: Add MHI controller")
Signed-off-by: default avatarJeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: default avatarPranjal Ramajor Asha Kanojiya <quic_pkanojiy@quicinc.com>
Reviewed-by: default avatarJacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231208163101.1295769-3-quic_jhugo@quicinc.com
parent c8b6f4ad

drivers/accel/qaic/mhi_controller.c

+14 −1
Original line number Diff line number Diff line
@@ -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;