From: Jeffrey Hugo Date: Fri, 8 Dec 2023 16:31:01 +0000 (-0700) Subject: accel/qaic: Implement quirk for SOC_HW_VERSION X-Git-Tag: v6.6.14~844 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f8d0c6d1992c6e91413883091dc8dd978c72d0b3;p=platform%2Fkernel%2Flinux-starfive.git accel/qaic: Implement quirk for SOC_HW_VERSION [ Upstream commit 4c8874c2a6512b9fe7285cab1a6910d9211a6cfb ] 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: a36bf7af868b ("accel/qaic: Add MHI controller") Signed-off-by: Jeffrey Hugo Reviewed-by: Pranjal Ramajor Asha Kanojiya Reviewed-by: Jacek Lawrynowicz Link: https://patchwork.freedesktop.org/patch/msgid/20231208163101.1295769-3-quic_jhugo@quicinc.com Signed-off-by: Sasha Levin --- diff --git a/drivers/accel/qaic/mhi_controller.c b/drivers/accel/qaic/mhi_controller.c index 5036e58..1405623 100644 --- a/drivers/accel/qaic/mhi_controller.c +++ b/drivers/accel/qaic/mhi_controller.c @@ -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;