From a4b2e6063cfeaab1160501acfb27e8618a7c693f Mon Sep 17 00:00:00 2001 From: Marek Vasut Date: Thu, 15 Dec 2022 16:20:23 +0100 Subject: firmware: xilinx: Clear IOCTL_SET_SD_TAPDELAY using PM_MMIO_WRITE In case the tap delay required by Arasan SDHCI is set to 0, the current embeddedsw firmware unconditionally writes IOU_SLCR SD_ITAPDLY to 0x100 (SD0_ITAPDLYENA=1, SD0_ITAPDLYSEL=0). Previous behavior was to keep the IOU_SLCR SD_ITAPDLY set to 0x0. There is some sort of difference in the behavior between SD0_ITAPDLYENA=1/0 with the same SD0_ITAPDLYSEL=0, even though the behavior should be identical -- zero delay added to rxclk_in line. The former breaks HS200 training in low temperature conditions. Write IOU_SLCR SD_ITAPDLY register to 0 using PM_MMIO_WRITE which seem to allow unrestricted WRITE access (and PM_MMIO_READ which allows read access) to the entire address space. This way, it is possible to work around the defect in IOCTL_SET_SD_TAPDELAY design which does not permit clearing SDx_ITAPDLYENA bit. Note that the embeddedsw firmware does not permit clearing the SD_ITAPDLY SD0_ITAPDLYENA bit, this bit can only ever be set by the firmware and it is often impossible to update the possibly broken firmware. Signed-off-by: Marek Vasut Link: https://lore.kernel.org/r/20221215152023.8387-1-marex@denx.de Signed-off-by: Michal Simek --- include/linux/firmware/xlnx-zynqmp.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux') diff --git a/include/linux/firmware/xlnx-zynqmp.h b/include/linux/firmware/xlnx-zynqmp.h index b986e267d149..eb88b4ba62f9 100644 --- a/include/linux/firmware/xlnx-zynqmp.h +++ b/include/linux/firmware/xlnx-zynqmp.h @@ -79,6 +79,10 @@ #define EVENT_ERROR_PSM_ERR1 (0x28108000U) #define EVENT_ERROR_PSM_ERR2 (0x2810C000U) +/* ZynqMP SD tap delay tuning */ +#define SD_ITAPDLY 0xFF180314 +#define SD_OTAPDLYSEL 0xFF180318 + enum pm_api_cb_id { PM_INIT_SUSPEND_CB = 30, PM_ACKNOWLEDGE_CB = 31, -- cgit