Merge patch series "Add OPP_LOW support for J7200"

Aniket Limaye <a-limaye@ti.com> says:

This series adds OPP_LOW spec data in k3_avs driver and enables a config
option to select the OPP_LOW performance point.

J7200 SOC supports OPP_LOW and OPP_NOM as two Operating Performance
Points as per (7.5 Operating Performance Points) section in the
Datasheet [0].
- A72SS/MSMC at 2 GHz/1GHz operation must use OPP_NOM.
- A72SS/MSMC at 1 GHz/500 MHz operation can use OPP_NOM or OPP_LOW
  voltage (though OPP_LOW voltage is recommended to reduce power
  consumption).

The actual OPP voltage for the device is read from the efuse and
updated in k3_avs_probe().

The default j7200 devicetree and k3_avs driver set OPP_NOM spec
frequency and voltage.

In the board init file, if K3_OPP_LOW config is enabled, Check if
OPP_LOW AVS voltage read from efuse is valid and update frequency (A72
and MSMC) and voltage (VDD_CPU) as per the OPP_LOW spec.

[0]: https://www.ti.com/lit/gpn/dra821u  (J7200 Datasheet)

Test logs:
https://gist.github.com/aniket-l/328ad93ed60c2419ed7be9f85e6b6075
- With series applied on master and CONFIG_K3_OPP_LOW enabled in
  j7200_evm_r5_defconfig
- Logs shown with and without efuse register programmed for OPP_0
  (Errors out if OPP_0 not found, programs OPP_LOW spec if found)
- Voltage update verified using 'i2c md 0x4c 0xe' in u-boot
- Frequency update verified using 'k3conf clock dump' in linux

Link: https://lore.kernel.org/r/20241119003617.1871183-1-a-limaye@ti.com

6 files changed, 143 insertions, 6 deletions

diff --git a/arch/arm/dts/k3-j7200-r5-common-proc-board.dts b/arch/arm/dts/k3-j7200-r5-common-proc-board.dts
index f096b102793..06fffe2a11b 100644
--- a/arch/arm/dts/k3-j7200-r5-common-proc-board.dts
+++ b/arch/arm/dts/k3-j7200-r5-common-proc-board.dts
@@ -23,11 +23,12 @@
 				<&k3_pds 202 TI_SCI_PD_EXCLUSIVE>,
 				<&k3_pds 4 TI_SCI_PD_EXCLUSIVE>;
 		resets = <&k3_reset 202 0>;
-		clocks = <&k3_clks 61 1>, <&k3_clks 202 2>;
-		clock-names = "gtc", "core";
-		assigned-clocks = <&k3_clks 202 2>, <&k3_clks 61 1>, <&k3_clks 323 0>;
-		assigned-clock-parents= <0>, <0>, <&k3_clks 323 2>;
-		assigned-clock-rates = <2000000000>, <200000000>;
+		clocks = <&k3_clks 61 1>, <&k3_clks 202 2>, <&k3_clks 4 1> ;
+		clock-names = "gtc", "core", "msmc";
+		assigned-clocks = <&k3_clks 202 2>, <&k3_clks 61 1>, <&k3_clks 4 1>,
+						  <&k3_clks 323 0>;
+		assigned-clock-parents= <0>, <0>, <0>, <&k3_clks 323 2>;
+		assigned-clock-rates = <2000000000>, <200000000>, <1000000000>;
 		ti,sci = <&dmsc>;
 		ti,sci-proc-id = <32>;
 		ti,sci-host-id = <10>;
diff --git a/arch/arm/mach-k3/j721e/j721e_init.c b/arch/arm/mach-k3/j721e/j721e_init.c
index e9ed8cb267c..805b28af8e4 100644
--- a/arch/arm/mach-k3/j721e/j721e_init.c
+++ b/arch/arm/mach-k3/j721e/j721e_init.c
@@ -19,6 +19,7 @@
 #include <fdtdec.h>
 #include <mmc.h>
 #include <remoteproc.h>
+#include <k3-avs.h>
 
 #include "../sysfw-loader.h"
 #include "../common.h"
@@ -39,6 +40,12 @@
 #define NB_THREADMAP_BIT0				BIT(0)
 #define NB_THREADMAP_BIT1				BIT(1)
 
+/* TISCI DEV ID for A72, MSMC Clock */
+#define DEV_A72SS0_CORE0_0_ID 202
+#define DEV_A72SS0_CORE0_0_ARM_CLK_CLK_ID 2
+#define DEV_A72SS0_CORE0_ID 4
+#define DEV_A72SS0_CORE0_MSMC_CLK_ID 1
+
 #ifdef CONFIG_K3_LOAD_SYSFW
 struct fwl_data cbass_hc_cfg0_fwls[] = {
 #if defined(CONFIG_TARGET_J721E_R5_EVM)
@@ -147,6 +154,78 @@ static void setup_navss_nb(void)
 	writel(NB_THREADMAP_BIT1, (uintptr_t)NAVSS0_NBSS_NB1_CFG_NB_THREADMAP);
 }
 
+#if defined(CONFIG_CPU_V7R) && defined(CONFIG_K3_AVS0)
+static int get_clock_index_by_dev_id(ofnode node, u32 dev_id, u32 clk_id)
+{
+	ofnode clknode;
+	int count, i;
+	struct ofnode_phandle_args phandle_args;
+
+	clknode = ofnode_by_compatible(ofnode_null(), "ti,k2g-sci-clk");
+	if (!ofnode_valid(clknode)) {
+		printf("%s: clock-controller not found\n", __func__);
+		return -ENODEV;
+	}
+
+	count = ofnode_count_phandle_with_args(node,  "assigned-clocks", "#clock-cells", 0);
+	for (i = 0; i < count; i++) {
+		if (ofnode_parse_phandle_with_args(node, "assigned-clocks",
+						   "#clock-cells", 0, i, &phandle_args)) {
+			printf("%s: Could not parse assigned-clocks at index %d\n", __func__, i);
+			continue;
+		}
+		if (ofnode_equal(clknode, phandle_args.node) &&
+		    phandle_args.args[0] == dev_id && phandle_args.args[1] == clk_id)
+			return i;
+	}
+	return -1;
+}
+
+static int fdt_fixup_a72ss_clock_frequency(void)
+{
+	int index, size;
+	u32 *rates;
+	ofnode node;
+
+	node = ofnode_by_compatible(ofnode_null(), "ti,am654-rproc");
+	if (!ofnode_valid(node)) {
+		printf("%s: A72 not found\n", __func__);
+		return -ENODEV;
+	}
+
+	rates = fdt_getprop_w(ofnode_to_fdt(node), ofnode_to_offset(node),
+			      "assigned-clock-rates", &size);
+	if (!rates) {
+		printf("%s: Wrong A72 assigned-clocks-rates configuration\n", __func__);
+		return -1;
+	}
+
+	/* Update A72 Clock Frequency to OPP_LOW spec */
+	index = get_clock_index_by_dev_id(node,
+					  DEV_A72SS0_CORE0_0_ID,
+					  DEV_A72SS0_CORE0_0_ARM_CLK_CLK_ID);
+	if (index < 0 || index >= (size / sizeof(u32))) {
+		printf("%s: Wrong A72 assigned-clocks configuration\n", __func__);
+		return -1;
+	}
+	rates[index] = cpu_to_fdt32(1000000000);
+	printf("Changed A72 CPU frequency to %dHz in DT\n", 1000000000);
+
+	/* Update MSMC Clock Frequency to OPP_LOW spec */
+	index = get_clock_index_by_dev_id(node,
+					  DEV_A72SS0_CORE0_ID,
+					  DEV_A72SS0_CORE0_MSMC_CLK_ID);
+	if (index < 0 || index >= (size / sizeof(u32))) {
+		printf("%s: Wrong A72 assigned-clocks configuration\n", __func__);
+		return -1;
+	}
+	rates[index] = cpu_to_fdt32(500000000);
+	printf("Changed MSMC frequency to %dHz in DT\n", 500000000);
+
+	return 0;
+}
+#endif
+
 /*
  * This uninitialized global variable would normal end up in the .bss section,
  * but the .bss is cleared between writing and reading this variable, so move
@@ -301,8 +380,19 @@ void board_init_f(ulong dummy)
 #if defined(CONFIG_CPU_V7R) && defined(CONFIG_K3_AVS0)
 	ret = uclass_get_device_by_driver(UCLASS_MISC, DM_DRIVER_GET(k3_avs),
 					  &dev);
-	if (ret)
+	if (ret) {
 		printf("AVS init failed: %d\n", ret);
+	} else if (IS_ENABLED(CONFIG_K3_OPP_LOW)) {
+		ret = k3_avs_check_opp(dev, J721E_VDD_MPU, AM6_OPP_LOW);
+		if (ret) {
+			printf("OPP_LOW: k3_avs_check_opp failed: %d\n", ret);
+		} else {
+			ret = fdt_fixup_a72ss_clock_frequency();
+			if (ret)
+				printf("OPP_LOW: fdt_fixup_a72ss_clock_frequency failed: %d\n",
+				       ret);
+		}
+	}
 #endif
 
 #if defined(CONFIG_K3_J721E_DDRSS)
diff --git a/arch/arm/mach-k3/r5/Kconfig b/arch/arm/mach-k3/r5/Kconfig
index 878087fbf56..12335880e10 100644
--- a/arch/arm/mach-k3/r5/Kconfig
+++ b/arch/arm/mach-k3/r5/Kconfig
@@ -1,6 +1,13 @@
 config K3_LOAD_SYSFW
 	bool
 
+config K3_OPP_LOW
+	depends on ARCH_K3 && K3_AVS0
+	bool "Enable OPP_LOW on supported TI K3 SoCs"
+	help
+	  Enabling this will allow Socs with the proper efuse to run at a lower
+	  MPU core voltage and adjust frequency according to SoC TRM
+
 config K3_QOS
 	bool "Enable Quality of Service (QoS) Settings for TI K3 SoCs"
 	default y if SOC_K3_AM62A7
diff --git a/configs/j7200_evm_r5_defconfig b/configs/j7200_evm_r5_defconfig
index f036a6fd46b..217759e5d1b 100644
--- a/configs/j7200_evm_r5_defconfig
+++ b/configs/j7200_evm_r5_defconfig
@@ -102,6 +102,7 @@ CONFIG_K3_SEC_PROXY=y
 CONFIG_FS_LOADER=y
 CONFIG_SPL_FS_LOADER=y
 CONFIG_K3_AVS0=y
+# CONFIG_K3_OPP_LOW is not set
 CONFIG_SUPPORT_EMMC_BOOT=y
 CONFIG_SPL_MMC_HS400_SUPPORT=y
 CONFIG_MMC_SDHCI=y
diff --git a/drivers/misc/k3_avs.c b/drivers/misc/k3_avs.c
index 99a18a109b7..0774e0a4c9e 100644
--- a/drivers/misc/k3_avs.c
+++ b/drivers/misc/k3_avs.c
@@ -121,6 +121,11 @@ static int k3_avs_program_voltage(struct k3_avs_privdata *priv,
 	if (!vd->supply)
 		return -ENODEV;
 
+	if (!volt) {
+		dev_err(priv->dev, "No efuse found for opp_%d\n", opp_id);
+		return -EINVAL;
+	}
+
 	vd->opp = opp_id;
 	vd->flags |= VD_FLAG_INIT_DONE;
 
@@ -193,6 +198,33 @@ static int match_opp(struct vd_data *vd, u32 freq)
 }
 
 /**
+ * k3_check_opp: Check for presence of opp efuse
+ * @dev: AVS device
+ * @vdd_id: voltage domain ID
+ * @opp_id: opp id to check if voltage is present
+ *
+ * Checks to see if an opp has voltage. k3_avs probe will populate
+ * voltage data if efuse is present. Returns 0 if data is valid.
+ */
+int k3_avs_check_opp(struct udevice *dev, int vdd_id, int opp_id)
+{
+	struct k3_avs_privdata *priv = dev_get_priv(dev);
+	struct vd_data *vd;
+	int volt;
+
+	vd = get_vd(priv, vdd_id);
+	if (!vd)
+		return -EINVAL;
+
+	volt = vd->opps[opp_id].volt;
+	if (volt)
+		return 0;
+
+	printf("No efuse found for opp_%d\n", opp_id);
+	return -EINVAL;
+}
+
+/**
  * k3_avs_notify_freq: Notify clock rate change towards AVS subsystem
  * @dev_id: Device ID for the clock to be changed
  * @clk_id: Clock ID for the clock to be changed
@@ -501,6 +533,10 @@ static struct vd_data j721e_vd_data[] = {
 		.dev_id = 202, /* J721E_DEV_A72SS0_CORE0 */
 		.clk_id = 2, /* ARM clock */
 		.opps = {
+			[AM6_OPP_LOW] = {
+				.volt = 0, /* voltage TBD after OPP fuse reading */
+				.freq = 1000000000,
+			},
 			[AM6_OPP_NOM] = {
 				.volt = 880000, /* TBD in DM */
 				.freq = 2000000000,
diff --git a/include/k3-avs.h b/include/k3-avs.h
index 1014d5d114d..5a973e4ed45 100644
--- a/include/k3-avs.h
+++ b/include/k3-avs.h
@@ -20,11 +20,13 @@
 
 #define NUM_OPPS		4
 
+#define AM6_OPP_LOW		0
 #define AM6_OPP_NOM		1
 #define AM6_OPP_OD		2
 #define AM6_OPP_TURBO		3
 
 int k3_avs_set_opp(struct udevice *dev, int vdd_id, int opp_id);
 int k3_avs_notify_freq(int dev_id, int clk_id, u32 freq);
+int k3_avs_check_opp(struct udevice *dev, int vdd_id, int opp_id);
 
 #endif