[PATCH v2 1/3] rockchip: rk356x: Implement checkboard() to print SoC variant

[Jonas Karlman]

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

  SoC:   RK3566 v1
  SoC:   RK3566 v2
  SoC:   RK3566T v2
  SoC:   RK3568 v2
  SoC:   RK3568B2 v2
  SoC:   RK3568J v2

when U-Boot proper is running.

  U-Boot 2025.01-rc1 (Nov 02 2024 - 20:21:06 +0000)

  Model: Generic RK3566/RK3568
  SoC:   RK3568J v2
  DRAM:  8 GiB (effective 7.7 GiB)

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

Also update rk356x-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-rk3568_defconfig change
---
 arch/arm/dts/rk356x-u-boot.dtsi        |  4 ++
 arch/arm/mach-rockchip/rk3568/rk3568.c | 67 ++++++++++++++++++++++++++
 2 files changed, 71 insertions(+)

diff --git a/arch/arm/dts/rk356x-u-boot.dtsi b/arch/arm/dts/rk356x-u-boot.dtsi
index 0a0943b462a9..24a976cf7e21 100644
--- a/arch/arm/dts/rk356x-u-boot.dtsi
+++ b/arch/arm/dts/rk356x-u-boot.dtsi
@@ -87,6 +87,10 @@
 	bootph-all;
 };
 
+&otp {
+	bootph-some-ram;
+};
+
 &pcfg_pull_none {
 	bootph-all;
 };
diff --git a/arch/arm/mach-rockchip/rk3568/rk3568.c b/arch/arm/mach-rockchip/rk3568/rk3568.c
index c9a32287e924..afa277ea5c61 100644
--- a/arch/arm/mach-rockchip/rk3568/rk3568.c
+++ b/arch/arm/mach-rockchip/rk3568/rk3568.c
@@ -4,6 +4,7 @@
  */
 
 #include <dm.h>
+#include <misc.h>
 #include <asm/armv8/mmu.h>
 #include <asm/arch-rockchip/bootrom.h>
 #include <asm/arch-rockchip/grf_rk3568.h>
@@ -139,3 +140,69 @@ int arch_cpu_init(void)
 #endif
 	return 0;
 }
+
+#define RK3568_OTP_CPU_CODE_OFFSET		0x02
+#define RK3568_OTP_SPECIFICATION_OFFSET		0x07
+#define RK3568_OTP_CPU_VERSION_OFFSET		0x08
+#define RK3568_OTP_PERFORMANCE_OFFSET		0x22
+
+int checkboard(void)
+{
+	u8 cpu_code[2], specification, package, cpu_version, performance;
+	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 0x66 or 0x35 0x68 */
+	ret = misc_read(dev, RK3568_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. 0x2 for RK3568B2 and 0xA for RK3568J */
+	ret = misc_read(dev, RK3568_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 RK3568B2 */
+	package = specification >> 5;
+	specification &= 0x1f;
+
+	/* cpu-version: chip version, e.g. second letter of lot number */
+	ret = misc_read(dev, RK3568_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;
+
+	/* performance: used to identify RK3566T SoC variant */
+	ret = misc_read(dev, RK3568_OTP_PERFORMANCE_OFFSET, &performance, 1);
+	if (ret < 0) {
+		debug("%s: could not read performance, ret=%d\n", __func__, ret);
+		return 0;
+	}
+	if (performance & 0x0f)
+		specification = 0x14; /* T-variant */
+
+	/* for RK3568J i.e. '@' + 0xA = 'J' */
+	suffix[0] = specification > 1 ? '@' + specification : '\0';
+	/* for RK3568B2 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