[PATCH v2 2/3] rockchip: rk3588: Implement checkboard() to print SoC variant

[Jonas Karlman]

Implement checkboard() to print current SoC model used by a board,
e.g. one of:

  SoC:   RK3582 v1
  SoC:   RK3588 v0
  SoC:   RK3588 v1
  SoC:   RK3588S v0
  SoC:   RK3588S v1
  SoC:   RK3588S2 v1

when U-Boot proper is running.

  U-Boot 2025.01-rc1 (Nov 02 2024 - 20:19:01 +0000)

  Model: Generic RK3588S/RK3588
  SoC:   RK3588S2 v1
  DRAM:  8 GiB

Information about the SoC model, variant and version is read from OTP.

Also update rk3588s-u-boot.dtsi to include OTP in U-Boot pre-reloc phase,
where checkboard() is called.

Signed-off-by: Jonas Karlman <jonas at kwiboo.se>
---
v2:
- Update commit message
- Update code comments
- Drop generic-rk3588_defconfig change
---
 arch/arm/dts/rk3588s-u-boot.dtsi       |  4 ++
 arch/arm/mach-rockchip/rk3588/rk3588.c | 58 ++++++++++++++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/arch/arm/dts/rk3588s-u-boot.dtsi b/arch/arm/dts/rk3588s-u-boot.dtsi
index 09d8b311cec5..8880d162b11c 100644
--- a/arch/arm/dts/rk3588s-u-boot.dtsi
+++ b/arch/arm/dts/rk3588s-u-boot.dtsi
@@ -69,6 +69,10 @@
 	bootph-all;
 };
 
+&otp {
+	bootph-some-ram;
+};
+
 &pcfg_pull_down {
 	bootph-all;
 };
diff --git a/arch/arm/mach-rockchip/rk3588/rk3588.c b/arch/arm/mach-rockchip/rk3588/rk3588.c
index e2dac2a5b806..f9da7a6f1477 100644
--- a/arch/arm/mach-rockchip/rk3588/rk3588.c
+++ b/arch/arm/mach-rockchip/rk3588/rk3588.c
@@ -4,6 +4,8 @@
  * Copyright (c) 2022 Edgeble AI Technologies Pvt. Ltd.
  */
 
+#include <dm.h>
+#include <misc.h>
 #include <spl.h>
 #include <asm/armv8/mmu.h>
 #include <asm/arch-rockchip/bootrom.h>
@@ -178,3 +180,59 @@ int arch_cpu_init(void)
 	return 0;
 }
 #endif
+
+#define RK3588_OTP_CPU_CODE_OFFSET		0x02
+#define RK3588_OTP_SPECIFICATION_OFFSET		0x06
+#define RK3588_OTP_CPU_VERSION_OFFSET		0x1c
+
+int checkboard(void)
+{
+	u8 cpu_code[2], specification, package, cpu_version;
+	struct udevice *dev;
+	char suffix[3];
+	int ret;
+
+	ret = uclass_get_device_by_driver(UCLASS_MISC,
+					  DM_DRIVER_GET(rockchip_otp), &dev);
+	if (ret) {
+		debug("%s: could not find otp device, ret=%d\n", __func__, ret);
+		return 0;
+	}
+
+	/* cpu-code: SoC model, e.g. 0x35 0x82 or 0x35 0x88 */
+	ret = misc_read(dev, RK3588_OTP_CPU_CODE_OFFSET, cpu_code, 2);
+	if (ret < 0) {
+		debug("%s: could not read cpu-code, ret=%d\n", __func__, ret);
+		return 0;
+	}
+
+	/* specification: SoC variant, e.g. 0xA for RK3588J and 0x13 for RK3588S */
+	ret = misc_read(dev, RK3588_OTP_SPECIFICATION_OFFSET, &specification, 1);
+	if (ret < 0) {
+		debug("%s: could not read specification, ret=%d\n", __func__, ret);
+		return 0;
+	}
+	/* package: likely SoC variant revision, 0x2 for RK3588S2 */
+	package = specification >> 5;
+	specification &= 0x1f;
+
+	/* cpu-version: chip version, e.g. second letter of lot number */
+	ret = misc_read(dev, RK3588_OTP_CPU_VERSION_OFFSET, &cpu_version, 1);
+	if (ret < 0) {
+		debug("%s: could not read cpu-version, ret=%d\n", __func__, ret);
+		return 0;
+	}
+	cpu_version >>= 3;
+	cpu_version &= 0x7;
+
+	/* for RK3588J i.e. '@' + 0xA = 'J' */
+	suffix[0] = specification > 1 ? '@' + specification : '\0';
+	/* for RK3588S2 i.e. '0' + 0x2 = '2' */
+	suffix[1] = package > 1 ? '0' + package : '\0';
+	suffix[2] = '\0';
+
+	printf("SoC:   RK%02x%02x%s v%u\n",
+	       cpu_code[0], cpu_code[1], suffix, cpu_version);
+
+	return 0;
+}
-- 
2.46.2