[PATCH v4 1/2] firmware: xilinx: Add pm api function for PL config reg readback

[Nava kishore Manne <nava.kishore.manne@amd.com>]

Adds PM API for performing Programmable Logic(PL) configuration
register readback. It provides an interface to the firmware(pmufw)
to readback the FPGA configuration register.

Signed-off-by: Nava kishore Manne <nava.kishore.manne@amd.com>
---
changes for v2:
              - None.

Changes for v3:
              - Updated API and config reg read-back handling logic
              - Updated the commit msg to align with the changes.

Changes for v4:
              - Fix some minor coding issues. No functional changes.
              - Updated Return value comments as suggested by Xu Yilun.

 drivers/firmware/xilinx/zynqmp.c     | 33 ++++++++++++++++++++++++++++
 include/linux/firmware/xlnx-zynqmp.h | 10 +++++++++
 2 files changed, 43 insertions(+)

diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
index ff5cabe70a2b..ca954e1119b5 100644
--- a/drivers/firmware/xilinx/zynqmp.c
+++ b/drivers/firmware/xilinx/zynqmp.c
@@ -941,6 +941,39 @@ int zynqmp_pm_fpga_get_status(u32 *value)
 }
 EXPORT_SYMBOL_GPL(zynqmp_pm_fpga_get_status);
 
+/**
+ * zynqmp_pm_fpga_get_config_status - Get the FPGA configuration status.
+ * @value: Buffer to store FPGA configuration status.
+ *
+ * This function provides access to the pmufw to get the FPGA configuration
+ * status
+ *
+ * Return: 0 on success, a negative value on error
+ */
+int zynqmp_pm_fpga_get_config_status(u32 *value)
+{
+	u32 buf, phys_lower_addr, phys_upper_addr;
+	u32 ret_payload[PAYLOAD_ARG_CNT];
+	int ret;
+
+	if (!value)
+		return -EINVAL;
+
+	phys_lower_addr = lower_32_bits((u64)&buf);
+	phys_upper_addr = upper_32_bits((u64)&buf);
+
+	ret = zynqmp_pm_invoke_fn(PM_FPGA_READ,
+				  XILINX_ZYNQMP_PM_FPGA_CONFIG_STAT_OFFSET,
+				  phys_lower_addr, phys_upper_addr,
+				  XILINX_ZYNQMP_PM_FPGA_READ_CONFIG_REG,
+				  ret_payload);
+
+	*value = ret_payload[1];
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(zynqmp_pm_fpga_get_config_status);
+
 /**
  * zynqmp_pm_pinctrl_request - Request Pin from firmware
  * @pin: Pin number to request
diff --git a/include/linux/firmware/xlnx-zynqmp.h b/include/linux/firmware/xlnx-zynqmp.h
index 76d2b3ebad84..29e8964f4297 100644
--- a/include/linux/firmware/xlnx-zynqmp.h
+++ b/include/linux/firmware/xlnx-zynqmp.h
@@ -70,6 +70,10 @@
 #define XILINX_ZYNQMP_PM_FPGA_FULL	0x0U
 #define XILINX_ZYNQMP_PM_FPGA_PARTIAL	BIT(0)
 
+/* FPGA Status Reg */
+#define XILINX_ZYNQMP_PM_FPGA_CONFIG_STAT_OFFSET	7U
+#define XILINX_ZYNQMP_PM_FPGA_READ_CONFIG_REG		0U
+
 /*
  * Node IDs for the Error Events.
  */
@@ -117,6 +121,7 @@ enum pm_api_id {
 	PM_CLOCK_GETRATE = 42,
 	PM_CLOCK_SETPARENT = 43,
 	PM_CLOCK_GETPARENT = 44,
+	PM_FPGA_READ = 46,
 	PM_SECURE_AES = 47,
 	PM_FEATURE_CHECK = 63,
 };
@@ -505,6 +510,7 @@ int zynqmp_pm_register_sgi(u32 sgi_num, u32 reset);
 int zynqmp_pm_set_sd_config(u32 node, enum pm_sd_config_type config, u32 value);
 int zynqmp_pm_set_gem_config(u32 node, enum pm_gem_config_type config,
 			     u32 value);
+int zynqmp_pm_fpga_get_config_status(u32 *value);
 #else
 static inline int zynqmp_pm_get_api_version(u32 *version)
 {
@@ -790,6 +796,10 @@ static inline int zynqmp_pm_set_gem_config(u32 node,
 	return -ENODEV;
 }
 
+static inline int zynqmp_pm_fpga_get_config_status(u32 *value)
+{
+	return -ENODEV;
+}
 #endif
 
 #endif /* __FIRMWARE_ZYNQMP_H__ */
-- 
2.25.1