diff options
Diffstat (limited to 'drivers/firmware/xilinx/zynqmp.c')
| -rw-r--r-- | drivers/firmware/xilinx/zynqmp.c | 27 |
1 files changed, 25 insertions, 2 deletions
diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c index 129f68d7a6f5..acd83d29c866 100644 --- a/drivers/firmware/xilinx/zynqmp.c +++ b/drivers/firmware/xilinx/zynqmp.c @@ -738,8 +738,31 @@ EXPORT_SYMBOL_GPL(zynqmp_pm_get_pll_frac_data); */ int zynqmp_pm_set_sd_tapdelay(u32 node_id, u32 type, u32 value) { - return zynqmp_pm_invoke_fn(PM_IOCTL, node_id, IOCTL_SET_SD_TAPDELAY, - type, value, NULL); + u32 reg = (type == PM_TAPDELAY_INPUT) ? SD_ITAPDLY : SD_OTAPDLYSEL; + u32 mask = (node_id == NODE_SD_0) ? GENMASK(15, 0) : GENMASK(31, 16); + + if (value) { + return zynqmp_pm_invoke_fn(PM_IOCTL, node_id, + IOCTL_SET_SD_TAPDELAY, + type, value, NULL); + } + + /* + * Work around completely misdesigned firmware API on Xilinx ZynqMP. + * The IOCTL_SET_SD_TAPDELAY firmware call allows the caller to only + * ever set IOU_SLCR SD_ITAPDLY Register SD0_ITAPDLYENA/SD1_ITAPDLYENA + * bits, but there is no matching call to clear those bits. If those + * bits are not cleared, SDMMC tuning may fail. + * + * Luckily, there are PM_MMIO_READ/PM_MMIO_WRITE calls which seem to + * allow complete unrestricted access to all address space, including + * IOU_SLCR SD_ITAPDLY Register and all the other registers, access + * to which was supposed to be protected by the current firmware API. + * + * Use PM_MMIO_READ/PM_MMIO_WRITE to re-implement the missing counter + * part of IOCTL_SET_SD_TAPDELAY which clears SDx_ITAPDLYENA bits. + */ + return zynqmp_pm_invoke_fn(PM_MMIO_WRITE, reg, mask, 0, 0, NULL); } EXPORT_SYMBOL_GPL(zynqmp_pm_set_sd_tapdelay); |