[PATCH v2] riscv: mpfs: Read and store FPGA design information on MPFS hardware.

When working with systems with multiple FPGA firmwares, it is sometimes
useful to be able to use the same U-Boot and script conditional behavior
based on the FPGA firmware ID and version number. This, allows, for
example, flashing new FPGA images without flashing the bootloader and
letting U-Boot and the Linux kernel adapt appropriately.

This does two things with the information:
1. Prints the FPGA design ID and version to the console as part of U-Boot
   startup, which is helpful to a human working with the board.
2. Stores the same information, plus the already-acquired FPGA serial
   number, in a new set of environment variables (serial_number,
   design_id, design_ver [the version], and design_backlevel
   [minimum-version backlevel]). These can be used in a U-Boot script to
   load different kernels, device trees, etc. depending on the currently
   installed firmware, which allows U-Boot and the kernel to adapt
   cleanly to FPGA firmware updates that change accessible peripherals
   etc.

Signed-off-by: Nathan Whitehorn <[email protected]>
---
Changes for v2:
- Rename environment variables to remove the pf_ prefix
- Remove portions of the patch that added properties to the device tree
- Style changes
- Rebase after a5f93037f28624c612288e2d97604d73e03af5a3

Thanks to Conor Dooley and Tim Ouyang for helpful suggestions.

 board/microchip/mpfs_generic/mpfs_generic.c | 26 ++++++++++
 drivers/misc/mpfs_syscontroller.c           | 54 +++++++++++++++++++++
 include/mpfs-mailbox.h                      |  2 +
 3 files changed, 82 insertions(+)

diff --git a/board/microchip/mpfs_generic/mpfs_generic.c b/board/microchip/mpfs_generic/mpfs_generic.c
index f57f5f4046b..4423dd1e38c 100644
--- a/board/microchip/mpfs_generic/mpfs_generic.c
+++ b/board/microchip/mpfs_generic/mpfs_generic.c
@@ -114,7 +114,10 @@ int board_late_init(void)
 {
 	u32 ret;
 	int node;
+	int idx;
 	u8 device_serial_number[16] = {0};
+	char serialstring[33], designid[33];
+	u16 designver, designbacklevel;
 	void *blob = (void *)gd->fdt_blob;
 	struct udevice *dev;
 	struct mpfs_sys_serv *sys_serv_priv;
@@ -144,6 +147,29 @@ int board_late_init(void)
 		return -EINVAL;
 	}
 
+	/* Store design info and serial number in environment */
+	memset(designid, 0, sizeof(designid));
+	memset(serialstring, 0, sizeof(serialstring));
+
+	ret = mpfs_syscontroller_read_design_info(sys_serv_priv, designid,
+			&designver, &designbacklevel);
+	if (ret) {
+		printf("Cannot read device design information\n");
+		return -EINVAL;
+	}
+	for (idx = 0; idx < 16; idx++)
+		sprintf(&serialstring[2*idx], "%02x", device_serial_number[idx]);
+
+	env_set("serial_number", serialstring);
+	env_set("design_id", designid);
+	env_set_ulong("design_ver", designver);
+	env_set_ulong("design_backlevel", designbacklevel);
+
+	printf("FPGA Design name: %s\n", designid);
+	printf("FPGA Serial: %s\n", serialstring);
+	printf("Design version number %d (backlevel %d)\n", designver,
+			designbacklevel);
+
 	/* Update MAC address with device serial number */
 	mac_addr[0] = 0x00;
 	mac_addr[1] = 0x04;
diff --git a/drivers/misc/mpfs_syscontroller.c b/drivers/misc/mpfs_syscontroller.c
index b9aea7e1181..07a788db76e 100644
--- a/drivers/misc/mpfs_syscontroller.c
+++ b/drivers/misc/mpfs_syscontroller.c
@@ -152,6 +152,60 @@ int mpfs_syscontroller_read_sernum(struct mpfs_sys_serv *sys_serv_priv, u8 *devi
 }
 EXPORT_SYMBOL(mpfs_syscontroller_read_sernum);
 
+/**
+ * mpfs_syscontroller_read_design_info() - Use system service to read FPGA design info
+ * @sys_serv_priv:	system service private data
+ * @designid:		30-byte string name of top module in FPGA logic design
+ * 			NB: null termination is not guaranteed
+ * @designver:		version number of the FPGA design
+ * @backlevel:		programmed minimum allowed FPGA design version
+ *
+ * Return: 0 if all went ok, else return appropriate error
+ */
+int mpfs_syscontroller_read_design_info(struct mpfs_sys_serv *sys_serv_priv,
+		u8 *designid, u16 *designver, u16 *backlevel)
+{
+	unsigned long timeoutsecs = 300;
+	u8 data[36];
+	int ret;
+
+	struct mpfs_mss_response response = {
+		.resp_status = 0U,
+		.resp_msg = (u32 *)data,
+		.resp_size = sizeof(data)};
+	struct mpfs_mss_msg msg = {
+		.cmd_opcode = 2,
+		.cmd_data_size = CMD_DATA_SIZE,
+		.response = &response,
+		.cmd_data = CMD_DATA,
+		.mbox_offset = MBOX_OFFSET,
+		.resp_offset = RESP_OFFSET};
+
+	ret = mpfs_syscontroller_run_service(sys_serv_priv->sys_controller, &msg);
+	if (ret) {
+		dev_err(sys_serv_priv->sys_controller->chan.dev, "Service failed: %d, abort\n", ret);
+		return ret;
+	}
+
+	/* Receive the response */
+	ret = mpfs_syscontroller_recv_response(sys_serv_priv->sys_controller, &msg, timeoutsecs);
+	if (ret)
+		return ret;
+
+	debug("%s: Read successful %s\n",
+	      __func__, sys_serv_priv->sys_controller->chan.dev->name);
+
+	if (designid != NULL)
+		memcpy(designid, &data[2], 30);
+	if (designver != NULL)
+		memcpy(designver, &data[32], 2);
+	if (backlevel != NULL)
+		memcpy(backlevel, &data[34], 2);
+
+	return 0;
+}
+EXPORT_SYMBOL(mpfs_syscontroller_read_design_info);
+
 static u16 mpfs_syscontroller_service_spi_copy(struct mpfs_sys_serv *sys_serv_priv, u64 dst_addr, u32 src_addr, u32 length)
 {
 	int ret;
diff --git a/include/mpfs-mailbox.h b/include/mpfs-mailbox.h
index 39c998e4c8d..bb9a162fb20 100644
--- a/include/mpfs-mailbox.h
+++ b/include/mpfs-mailbox.h
@@ -61,6 +61,8 @@ int mpfs_syscontroller_run_service(struct mpfs_syscontroller_priv *sys_controlle
 int mpfs_syscontroller_recv_response(struct mpfs_syscontroller_priv
 	*sys_controller, struct mpfs_mss_msg *msg, unsigned long timeout_ms);
 int mpfs_syscontroller_read_sernum(struct mpfs_sys_serv *sys_serv_priv, u8 *device_serial_number);
+int mpfs_syscontroller_read_design_info(struct mpfs_sys_serv *sys_serv_priv,
+		u8 *designid, u16 *designver, u16 *backlevel);
 void mpfs_syscontroller_process_dtbo(struct mpfs_sys_serv *sys_serv_priv);
 struct mpfs_syscontroller_priv *mpfs_syscontroller_get(struct udevice *dev);
 
-- 
2.43.0