Merge tag 'zynqmp-soc-for-v6.3' of https://github.com/Xilinx/linux-xlnx into soc/drivers

arm64: ZynqMP SoC changes for v6.3

Firmware changes
- fix memory leak in error path inside notification code
- trivial comment cleanup
- add workaround for SD tap delay programming with old PMUFW

* tag 'zynqmp-soc-for-v6.3' of https://github.com/Xilinx/linux-xlnx:
  firmware: xilinx: Clear IOCTL_SET_SD_TAPDELAY using PM_MMIO_WRITE
  firmware: xilinx: Remove kernel-doc marking in the code
  driver: soc: xilinx: fix memory leak in xlnx_add_cb_for_notify_event()

Link: https://lore.kernel.org/r/42be5129-3ca2-ddbc-ac3b-6448245b61c2@monstr.eu
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

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);