Re: [PATCH v6 1/5] qcom: spm: Add Subsystem Power Manager driver

[Lina Iyer <lina.iyer@linaro.org>]

On Tue, Sep 23 2014 at 17:51 -0600, Lina Iyer wrote:
>Based on work by many authors, available at codeaurora.org
>
>SPM is a hardware block that controls the peripheral logic surrounding
>the application cores (cpu/l$). When the core executes WFI instruction,
>the SPM takes over the putting the core in low power state as
>configured. The wake up for the SPM is an interrupt at the GIC, which
>then completes the rest of low power mode sequence and brings the core
>out of low power mode.
>
>The SPM has a set of control registers that configure the SPMs
>individually based on the type of the core and the runtime conditions.
>SPM is a finite state machine block to which a sequence is provided and
>it interprets the bytes  and executes them in sequence. Each low power
>mode that the core can enter into is provided to the SPM as a sequence.
>
>Configure the SPM to set the core (cpu or L2) into its low power mode,
>the index of the first command in the sequence is set in the SPM_CTL
>register. When the core executes ARM wfi instruction, it triggers the
>SPM state machine to start executing from that index. The SPM state
>machine waits until the interrupt occurs and starts executing the rest
>of the sequence until it hits the end of the sequence. The end of the
>sequence jumps the core out of its low power mode.
>
>Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
>[lina: simplify the driver for initial submission, clean up and update
>commit text]
>---
> Documentation/devicetree/bindings/arm/msm/spm.txt |  43 +++
> drivers/soc/qcom/Kconfig                          |   8 +
> drivers/soc/qcom/Makefile                         |   1 +
> drivers/soc/qcom/spm.c                            | 388 ++++++++++++++++++++++
> include/soc/qcom/spm.h                            |  38 +++
> 5 files changed, 478 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/arm/msm/spm.txt
> create mode 100644 drivers/soc/qcom/spm.c
> create mode 100644 include/soc/qcom/spm.h
>
>diff --git a/Documentation/devicetree/bindings/arm/msm/spm.txt b/Documentation/devicetree/bindings/arm/msm/spm.txt
>new file mode 100644
>index 0000000..2ff2454
>--- /dev/null
>+++ b/Documentation/devicetree/bindings/arm/msm/spm.txt
>@@ -0,0 +1,43 @@
>+* Subsystem Power Manager (SPM)
>+
>+Qualcomm Snapdragons have SPM hardware blocks to control the Application
>+Processor Sub-System power. These SPM blocks run individual state machine
>+to determine what the core (L2 or Krait/Scorpion) would do when the WFI
>+instruction is executed by the core.
>+
>+The devicetree representation of the SPM block should be:
>+
>+Required properties
>+
>+- compatible: Must be -
>+		 "qcom,spm-v2.1"
>+- reg: The physical address and the size of the SPM's memory mapped registers
>+- qcom,cpu: phandle for the CPU that the SPM block is attached to.
>+	This field is required on only for SPMs that control the CPU.
>+- qcom,saw2-clk-div: SAW2 configuration register to program the SPM runtime
>+	clocks. The register for this property is MSM_SPM_REG_SAW2_CFG.
>+- qcom,saw2-delays: The SPM delay values that SPM sequences would refer to.
>+	The register for this property is MSM_SPM_REG_SAW2_SPM_DLY.
>+- qcom,saw2-enable: The SPM control register to enable/disable the sleep state
>+	machine. The register for this property is MSM_SPM_REG_SAW2_SPM_CTL.
>+
>+Optional properties
>+
>+- qcom,saw2-spm-cmd-wfi: The WFI command sequence
>+- qcom,saw2-spm-cmd-spc: The Standalone PC command sequence
>+
>+Example:
>+	spm@f9089000 {
>+		compatible = "qcom,spm-v2.1";
>+		#address-cells = <1>;
>+		#size-cells = <1>;
>+		reg = <0xf9089000 0x1000>;
>+		qcom,cpu = <&CPU0>;
>+		qcom,saw2-clk-div = <0x1>;
>+		qcom,saw2-delays = <0x20000400>;
>+		qcom,saw2-enable = <0x1>;
>+		qcom,saw2-spm-cmd-wfi = [03 0b 0f];
>+		qcom,saw2-spm-cmd-spc = [00 20 50 80 60 70 10 92
>+				a0 b0 03 68 70 3b 92 a0 b0
>+				82 2b 50 10 30 02 22 30 0f];
>+	};
>diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
>index 7dcd554..cd249c4 100644
>--- a/drivers/soc/qcom/Kconfig
>+++ b/drivers/soc/qcom/Kconfig
>@@ -11,3 +11,11 @@ config QCOM_GSBI
>
> config QCOM_SCM
> 	bool
>+
>+config QCOM_PM
>+	bool "Qualcomm Power Management"
>+	depends on PM && ARCH_QCOM
>+	help
>+	  QCOM Platform specific power driver to manage cores and L2 low power
>+	  modes. It interface with various system drivers to put the cores in
>+	  low power modes.
>diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
>index 70d52ed..20b329f 100644
>--- a/drivers/soc/qcom/Makefile
>+++ b/drivers/soc/qcom/Makefile
>@@ -1,3 +1,4 @@
> obj-$(CONFIG_QCOM_GSBI)	+=	qcom_gsbi.o
>+obj-$(CONFIG_QCOM_PM)	+=	spm.o
> CFLAGS_scm.o :=$(call as-instr,.arch_extension sec,-DREQUIRES_SEC=1)
> obj-$(CONFIG_QCOM_SCM) += scm.o scm-boot.o
>diff --git a/drivers/soc/qcom/spm.c b/drivers/soc/qcom/spm.c
>new file mode 100644
>index 0000000..1fa6a96
>--- /dev/null
>+++ b/drivers/soc/qcom/spm.c
>@@ -0,0 +1,388 @@
>+/* Copyright (c) 2011-2014, The Linux Foundation. All rights reserved.
>+ *
>+ * This program is free software; you can redistribute it and/or modify
>+ * it under the terms of the GNU General Public License version 2 and
>+ * only version 2 as published by the Free Software Foundation.
>+ *
>+ * This program is distributed in the hope that it will be useful,
>+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
>+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>+ * GNU General Public License for more details.
>+ *
>+ */
>+
>+#include <linux/module.h>
>+#include <linux/kernel.h>
>+#include <linux/delay.h>
>+#include <linux/init.h>
>+#include <linux/io.h>
>+#include <linux/slab.h>
>+#include <linux/of.h>
>+#include <linux/of_address.h>
>+#include <linux/err.h>
>+#include <linux/platform_device.h>
>+
>+#include <soc/qcom/spm.h>
>+
>+#define NUM_SEQ_ENTRY 32
>+#define SPM_CTL_ENABLE BIT(0)
>+
>+enum {
>+	MSM_SPM_REG_SAW2_CFG,
>+	MSM_SPM_REG_SAW2_AVS_CTL,
>+	MSM_SPM_REG_SAW2_AVS_HYSTERESIS,
>+	MSM_SPM_REG_SAW2_SPM_CTL,
>+	MSM_SPM_REG_SAW2_PMIC_DLY,
>+	MSM_SPM_REG_SAW2_AVS_LIMIT,
>+	MSM_SPM_REG_SAW2_AVS_DLY,
>+	MSM_SPM_REG_SAW2_SPM_DLY,
>+	MSM_SPM_REG_SAW2_PMIC_DATA_0,
>+	MSM_SPM_REG_SAW2_PMIC_DATA_1,
>+	MSM_SPM_REG_SAW2_PMIC_DATA_2,
>+	MSM_SPM_REG_SAW2_PMIC_DATA_3,
>+	MSM_SPM_REG_SAW2_PMIC_DATA_4,
>+	MSM_SPM_REG_SAW2_PMIC_DATA_5,
>+	MSM_SPM_REG_SAW2_PMIC_DATA_6,
>+	MSM_SPM_REG_SAW2_PMIC_DATA_7,
>+	MSM_SPM_REG_SAW2_RST,
>+
>+	MSM_SPM_REG_NR_INITIALIZE = MSM_SPM_REG_SAW2_RST,
>+
>+	MSM_SPM_REG_SAW2_ID,
>+	MSM_SPM_REG_SAW2_SECURE,
>+	MSM_SPM_REG_SAW2_STS0,
>+	MSM_SPM_REG_SAW2_STS1,
>+	MSM_SPM_REG_SAW2_STS2,
>+	MSM_SPM_REG_SAW2_VCTL,
>+	MSM_SPM_REG_SAW2_SEQ_ENTRY,
>+	MSM_SPM_REG_SAW2_SPM_STS,
>+	MSM_SPM_REG_SAW2_AVS_STS,
>+	MSM_SPM_REG_SAW2_PMIC_STS,
>+	MSM_SPM_REG_SAW2_VERSION,
>+
>+	MSM_SPM_REG_NR,
>+};
>+
>+static u32 reg_offsets_saw2_v2_1[MSM_SPM_REG_NR] = {
>+	[MSM_SPM_REG_SAW2_SECURE]		= 0x00,
>+	[MSM_SPM_REG_SAW2_ID]			= 0x04,
>+	[MSM_SPM_REG_SAW2_CFG]			= 0x08,
>+	[MSM_SPM_REG_SAW2_SPM_STS]		= 0x0C,
>+	[MSM_SPM_REG_SAW2_AVS_STS]		= 0x10,
>+	[MSM_SPM_REG_SAW2_PMIC_STS]		= 0x14,
>+	[MSM_SPM_REG_SAW2_RST]			= 0x18,
>+	[MSM_SPM_REG_SAW2_VCTL]			= 0x1C,
>+	[MSM_SPM_REG_SAW2_AVS_CTL]		= 0x20,
>+	[MSM_SPM_REG_SAW2_AVS_LIMIT]		= 0x24,
>+	[MSM_SPM_REG_SAW2_AVS_DLY]		= 0x28,
>+	[MSM_SPM_REG_SAW2_AVS_HYSTERESIS]	= 0x2C,
>+	[MSM_SPM_REG_SAW2_SPM_CTL]		= 0x30,
>+	[MSM_SPM_REG_SAW2_SPM_DLY]		= 0x34,
>+	[MSM_SPM_REG_SAW2_PMIC_DATA_0]		= 0x40,
>+	[MSM_SPM_REG_SAW2_PMIC_DATA_1]		= 0x44,
>+	[MSM_SPM_REG_SAW2_PMIC_DATA_2]		= 0x48,
>+	[MSM_SPM_REG_SAW2_PMIC_DATA_3]		= 0x4C,
>+	[MSM_SPM_REG_SAW2_PMIC_DATA_4]		= 0x50,
>+	[MSM_SPM_REG_SAW2_PMIC_DATA_5]		= 0x54,
>+	[MSM_SPM_REG_SAW2_PMIC_DATA_6]		= 0x58,
>+	[MSM_SPM_REG_SAW2_PMIC_DATA_7]		= 0x5C,
>+	[MSM_SPM_REG_SAW2_SEQ_ENTRY]		= 0x80,
>+	[MSM_SPM_REG_SAW2_VERSION]		= 0xFD0,
>+};
I should probably remove the registers that we would not ever read/write
in this driver.

>+
>+struct spm_of {
>+	char *key;
>+	u32 id;
>+};
>+
>+struct msm_spm_mode {
>+	u32 mode;
>+	u32 start_addr;
>+};
>+
>+struct msm_spm_driver_data {
>+	void __iomem *reg_base_addr;
>+	u32 *reg_offsets;
>+	struct msm_spm_mode *modes;
>+	u32 num_modes;
>+};
>+
>+struct msm_spm_device {
>+	bool initialized;
>+	struct msm_spm_driver_data drv;
>+};
>+
>+static DEFINE_PER_CPU_SHARED_ALIGNED(struct msm_spm_device, msm_cpu_spm_device);
>+
>+static const struct of_device_id msm_spm_match_table[] __initconst;
>+
>+static int msm_spm_drv_set_low_power_mode(struct msm_spm_driver_data *drv,
>+						u32 mode)
>+{
>+	int i;
>+	u32 start_addr = 0;
>+	u32 ctl_val;
>+
>+	for (i = 0; i < drv->num_modes; i++) {
>+		if (drv->modes[i].mode == mode) {
>+			start_addr = drv->modes[i].start_addr;
>+			break;
>+		}
>+	}
>+
>+	if (i == drv->num_modes)
>+		return -EINVAL;
>+
>+	/* Update bits 10:4 in the SPM CTL register */
>+	ctl_val = readl_relaxed(drv->reg_base_addr +
>+			drv->reg_offsets[MSM_SPM_REG_SAW2_SPM_CTL]);
>+	start_addr &= 0x7F;
>+	start_addr <<= 4;
>+	ctl_val &= 0xFFFFF80F;
>+	ctl_val |= start_addr;
>+	writel_relaxed(ctl_val, drv->reg_base_addr +
>+			drv->reg_offsets[MSM_SPM_REG_SAW2_SPM_CTL]);
>+	/* Ensure we have written the start address */
>+	wmb();
>+
>+	return 0;
>+}
>+
>+static int msm_spm_drv_set_spm_enable(struct msm_spm_driver_data *drv,
>+					bool enable)
>+{
>+	u32 value = enable ? 0x01 : 0x00;
>+	u32 ctl_val;
>+
>+	ctl_val = readl_relaxed(drv->reg_base_addr +
>+			drv->reg_offsets[MSM_SPM_REG_SAW2_SPM_CTL]);
>+
>+	/* Update SPM_CTL to enable/disable the SPM */
>+	if ((ctl_val & SPM_CTL_ENABLE) != value) {
>+		/* Clear the existing value and update */
>+		ctl_val &= ~0x1;
>+		ctl_val |= value;
>+		writel_relaxed(ctl_val, drv->reg_base_addr +
>+			drv->reg_offsets[MSM_SPM_REG_SAW2_SPM_CTL]);
>+
>+		/* Ensure we have enabled/disabled before returning */
>+		wmb();
>+	}
>+
>+	return 0;
>+}
>+
>+/**
>+ * msm_spm_set_low_power_mode() - Configure SPM start address for low power mode
>+ * @mode: SPM LPM mode to enter
>+ */
>+int msm_spm_set_low_power_mode(u32 mode)
>+{
>+	struct msm_spm_device *dev = &__get_cpu_var(msm_cpu_spm_device);
>+	int ret = -EINVAL;
>+
>+	if (!dev->initialized)
>+		return -ENXIO;
>+
>+	if (mode == MSM_SPM_MODE_DISABLED)
>+		ret = msm_spm_drv_set_spm_enable(&dev->drv, false);
>+	else if (!msm_spm_drv_set_spm_enable(&dev->drv, true))
>+		ret = msm_spm_drv_set_low_power_mode(&dev->drv, mode);
>+
>+	return ret;
>+}
>+EXPORT_SYMBOL(msm_spm_set_low_power_mode);
>+
>+static void append_seq_data(u32 *reg_seq_entry, u8 *cmd, u32 *offset)
>+{
>+	u32 cmd_w;
>+	u32 offset_w = *offset / 4;
>+	u8 last_cmd;
>+
>+	while (1) {
>+		int i;
>+
>+		cmd_w = 0;
>+		last_cmd = 0;
>+		cmd_w = reg_seq_entry[offset_w];
>+
>+		for (i = (*offset % 4); i < 4; i++) {
>+			last_cmd = *(cmd++);
>+			cmd_w |=  last_cmd << (i * 8);
>+			(*offset)++;
>+			if (last_cmd == 0x0f)
>+				break;
>+		}
>+
>+		reg_seq_entry[offset_w++] = cmd_w;
>+		if (last_cmd == 0x0f)
>+			break;
>+	}
>+}
>+
>+static int msm_spm_seq_init(struct msm_spm_device *spm_dev,
>+			struct platform_device *pdev)
>+{
>+	int i;
>+	u8 *cmd;
>+	void *addr;
>+	u32 val;
>+	u32 count = 0;
>+	int offset = 0;
>+	struct msm_spm_mode modes[MSM_SPM_MODE_NR];
>+	u32 sequences[NUM_SEQ_ENTRY/4] = {0};
>+	struct msm_spm_driver_data *drv = &spm_dev->drv;
>+
>+	/* SPM sleep sequences */
>+	struct spm_of mode_of_data[] = {
>+		{"qcom,saw2-spm-cmd-wfi", MSM_SPM_MODE_CLOCK_GATING},
>+		{"qcom,saw2-spm-cmd-spc", MSM_SPM_MODE_POWER_COLLAPSE},
>+	};
>+
>+	/**
>+	 * Compose the u32 array based on the individual bytes of the SPM
>+	 * sequence for each low power mode that we read from the DT.
>+	 * The sequences are appended if there is space available in the
>+	 * u32 after the end of the previous sequence.
>+	 */
>+
>+	for (i = 0; i < ARRAY_SIZE(mode_of_data); i++) {
>+		cmd = (u8 *)of_get_property(pdev->dev.of_node,
>+						mode_of_data[i].key, &val);
>+		if (!cmd)
>+			continue;
>+		/* The last in the sequence should be 0x0F */
>+		if (cmd[val - 1] != 0x0F)
>+			continue;
>+		modes[count].mode = mode_of_data[i].id;
>+		modes[count].start_addr = offset;
>+		append_seq_data(&sequences[0], cmd, &offset);
>+		count++;
>+	}
>+
>+	/* Write the idle state sequences to SPM */
>+	drv->modes = devm_kcalloc(&pdev->dev, count,
>+					sizeof(modes[0]), GFP_KERNEL);
>+	if (!drv->modes)
>+		return -ENOMEM;
>+
>+	drv->num_modes = count;
>+	memcpy(drv->modes, modes, sizeof(modes[0]) * count);
>+
>+	/* Flush the integer array */
>+	addr = drv->reg_base_addr +
>+			drv->reg_offsets[MSM_SPM_REG_SAW2_SEQ_ENTRY];
>+	for (i = 0; i < ARRAY_SIZE(sequences); i++, addr += 4)
>+		writel_relaxed(sequences[i], addr);
>+
>+	/* Ensure we flush the writes */
>+	wmb();
>+
>+	return 0;
>+}
>+
>+static struct msm_spm_device *msm_spm_get_device(struct platform_device *pdev)
>+{
>+	struct msm_spm_device *dev = NULL;
>+	struct device_node *cpu_node;
>+	u32 cpu;
>+
>+	cpu_node = of_parse_phandle(pdev->dev.of_node, "qcom,cpu", 0);
>+	if (cpu_node) {
>+		for_each_possible_cpu(cpu) {
>+			if (of_get_cpu_node(cpu, NULL) == cpu_node)
>+				dev = &per_cpu(msm_cpu_spm_device, cpu);
>+		}
>+	}
>+
>+	return dev;
>+}
>+
>+static int msm_spm_dev_probe(struct platform_device *pdev)
>+{
>+	int ret;
>+	int i;
>+	u32 val;
>+	struct msm_spm_device *spm_dev;
>+	struct resource *res;
>+	const struct of_device_id *match_id;
>+
>+	/* SPM Configuration registers */
>+	struct spm_of spm_of_data[] = {
>+		{"qcom,saw2-clk-div", MSM_SPM_REG_SAW2_CFG},
>+		{"qcom,saw2-enable", MSM_SPM_REG_SAW2_SPM_CTL},
>+		{"qcom,saw2-delays", MSM_SPM_REG_SAW2_SPM_DLY},
>+	};
>+
>+	 /* Get the right SPM device */
>+	spm_dev = msm_spm_get_device(pdev);
>+	if (IS_ERR_OR_NULL(spm_dev))
>+		return -EINVAL;
>+
>+	/* Get the SPM start address */
>+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>+	if (!res) {
>+		ret = -EINVAL;
>+		goto fail;
>+	}
>+	spm_dev->drv.reg_base_addr = devm_ioremap(&pdev->dev, res->start,
>+					resource_size(res));
>+	if (!spm_dev->drv.reg_base_addr) {
>+		ret = -ENOMEM;
>+		goto fail;
>+	}
>+
>+	match_id = of_match_node(msm_spm_match_table, pdev->dev.of_node);
>+	if (!match_id)
>+		return -ENODEV;
>+
>+	/* Use the register offsets for the SPM version in use */
>+	spm_dev->drv.reg_offsets = (u32 *)match_id->data;
>+	if (!spm_dev->drv.reg_offsets)
>+		return -EFAULT;
>+
>+	/* Read the SPM idle state sequences */
>+	ret = msm_spm_seq_init(spm_dev, pdev);
>+	if (ret)
>+		return ret;
>+
>+	/* Read the SPM register values */
>+	for (i = 0; i < ARRAY_SIZE(spm_of_data); i++) {
>+		ret = of_property_read_u32(pdev->dev.of_node,
>+					spm_of_data[i].key, &val);
>+		if (ret)
>+			continue;
>+		writel_relaxed(val, spm_dev->drv.reg_base_addr +
>+				spm_dev->drv.reg_offsets[spm_of_data[i].id]);
>+	}
>+
>+	/* Flush all writes */
>+	wmb();
>+
>+	spm_dev->initialized = true;
>+	return ret;
>+fail:
>+	dev_err(&pdev->dev, "SPM device probe failed: %d\n", ret);
>+	return ret;
>+}
>+
>+static const struct of_device_id msm_spm_match_table[] __initconst = {
>+	{.compatible = "qcom,spm-v2.1", .data = reg_offsets_saw2_v2_1},
>+	{ },
>+};
>+
>+
>+static struct platform_driver msm_spm_device_driver = {
>+	.probe = msm_spm_dev_probe,
>+	.driver = {
>+		.name = "spm",
>+		.owner = THIS_MODULE,
>+		.of_match_table = msm_spm_match_table,
>+	},
>+};
>+
>+static int __init msm_spm_device_init(void)
>+{
>+	return platform_driver_register(&msm_spm_device_driver);
>+}
>+device_initcall(msm_spm_device_init);
>diff --git a/include/soc/qcom/spm.h b/include/soc/qcom/spm.h
>new file mode 100644
>index 0000000..29686ef
>--- /dev/null
>+++ b/include/soc/qcom/spm.h
>@@ -0,0 +1,38 @@
>+/* Copyright (c) 2010-2014, The Linux Foundation. All rights reserved.
>+ *
>+ * This program is free software; you can redistribute it and/or modify
>+ * it under the terms of the GNU General Public License version 2 and
>+ * only version 2 as published by the Free Software Foundation.
>+ *
>+ * This program is distributed in the hope that it will be useful,
>+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
>+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>+ * GNU General Public License for more details.
>+ */
>+
>+#ifndef __QCOM_SPM_H
>+#define __QCOM_SPM_H
>+
>+enum {
>+	MSM_SPM_MODE_DISABLED,
>+	MSM_SPM_MODE_CLOCK_GATING,
>+	MSM_SPM_MODE_RETENTION,
>+	MSM_SPM_MODE_GDHS,
>+	MSM_SPM_MODE_POWER_COLLAPSE,
>+	MSM_SPM_MODE_NR
>+};
>+
>+struct msm_spm_device;
>+
>+#if defined(CONFIG_QCOM_PM)
>+
>+int msm_spm_set_low_power_mode(u32 mode);
>+
>+#else
>+
>+static inline int msm_spm_set_low_power_mode(u32 mode)
>+{ return -ENOSYS; }
>+
>+#endif  /* CONFIG_QCOM_PM */
>+
>+#endif  /* __QCOM_SPM_H */
>-- 
>1.9.1
>