Re: [PATCH v4 4/8] qcom: spm-devices: Add SPM device manager for the SoC

[Stephen Boyd <sboyd@codeaurora.org>]

On 08/19/14 15:15, Lina Iyer wrote:
> diff --git a/Documentation/devicetree/bindings/arm/msm/spm.txt b/Documentation/devicetree/bindings/arm/msm/spm.txt
> new file mode 100644
> index 0000000..318e024
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/msm/spm.txt

We already have a binding document for SAW. Please add stuff there
because SPM is just a component of SAW.

> @@ -0,0 +1,47 @@
> +* Subsystem Power Manager (SAW2)
> +
> +S4 generation of MSMs 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: Could be one of -
> +		"qcom,spm-v2.1"
> +		"qcom,spm-v3.0"
> +- 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.

We have a phandle from the CPU/L2 to the SAW, so this isn't necessary.

> +- qcom,saw2-cfg: SAW2 configuration register

Why? Compatible should indicate where this register is.

> +- qcom,saw2-spm-dly: Provides the values for the SPM delay command in the SPM
> +	sequence

This is actually three values packed into one register for three
different selectable delays, right? We don't typically do register jam
tables in DT. Perhaps it should be split out into 3 different
properties. Or maybe it shouldn't be specified in DT at all and should
be determined algorithmically from the command sequences? From what I
can tell most of the sequences don't even use these delays.

> +- qcom,saw2-spm-ctl: The SPM control register

Why? Compatible should indicate where this register is.

> +
> +Optional properties
> +
> +- qcom,saw2-spm-cmd-wfi: The WFI command sequence
> +- qcom,saw2-spm-cmd-ret: The Retention command sequence
> +- qcom,saw2-spm-cmd-spc: The Standalone PC command sequence
> +- qcom,saw2-spm-cmd-pc: The Power Collapse command sequence. This sequence may
> +	turn off other SoC components.
> +- qcom,saw2-spm-cmd-gdhs: GDHS (Globally Distributed Head Switch) command
> +	sequence. This sequence will retain the memory but turn off the logic.

I wonder if these should be properties of the idle states? That way the
driver isn't searching for them by name in DT, instead it knows what
state is associated with what sequence that the SPM needs to have
programmed.

> +-
> +Example:
> +	spm@f9089000 {
> +		compatible = "qcom,spm-v2.1";
> +		#address-cells = <1>;
> +		#size-cells = <1>;

Why is this in the example? Are there subnodes?

> +		reg = <0xf9089000 0x1000>;
> +		qcom,cpu = <&CPU0>;
> +		qcom,saw2-cfg = <0x1>;
> +		qcom,saw2-spm-dly= <0x20000400>;
> +		qcom,saw2-spm-ctl = <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/spm-devices.c b/drivers/soc/qcom/spm-devices.c
> new file mode 100644
> index 0000000..2175a81
> --- /dev/null
> +++ b/drivers/soc/qcom/spm-devices.c
> @@ -0,0 +1,198 @@
> +/* 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>
> +
> +#include "spm-drv.h"
> +
> +/**
> + * All related information for an SPM device
> + * Helps manage the collective.
> + */
> +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);
> +
> +/**
> + * 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(unsigned int 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 int get_cpu_id(struct device_node *node)
> +{
> +	struct device_node *cpu_node;
> +	u32 cpu;
> +	int ret = -EINVAL;
> +	char *key = "qcom,cpu";
> +
> +	cpu_node = of_parse_phandle(node, key, 0);
> +	if (cpu_node) {
> +		for_each_possible_cpu(cpu) {
> +			if (of_get_cpu_node(cpu, NULL) == cpu_node)
> +				return cpu;
> +		}
> +	}
> +	return ret;
> +}
> +
> +static struct msm_spm_device *msm_spm_get_device(struct platform_device *pdev)
> +{
> +	struct msm_spm_device *dev = NULL;
> +	int cpu = get_cpu_id(pdev->dev.of_node);
> +
> +	if ((cpu >= 0) && cpu < num_possible_cpus())
> +		dev = &per_cpu(msm_cpu_spm_device, cpu);
> +
> +	return dev;
> +}
> +
> +static int msm_spm_dev_probe(struct platform_device *pdev)
> +{
> +	int ret;
> +	int i;
> +	struct device_node *node = pdev->dev.of_node;
> +	char *key;
> +	uint32_t val;
> +	struct msm_spm_mode modes[MSM_SPM_MODE_NR];
> +	struct msm_spm_device *spm_dev;
> +	struct resource *res;
> +	uint32_t mode_count = 0;
> +
> +	struct spm_of {
> +		char *key;
> +		uint32_t 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},
> +	};
> +
> +	/* 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},
> +		{"qcom,saw2-spm-cmd-ret", MSM_SPM_MODE_RETENTION},
> +	};
> +
> +	 /* Get the right SPM device */
> +	spm_dev = msm_spm_get_device(pdev);
> +	if (IS_ERR_OR_NULL(spm_dev))
> +		return -EINVAL;
> +
> +	/* Get the SAW 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;
> +	}
> +
> +	/* Read the SPM configuration register values */
> +	for (i = 0; i < ARRAY_SIZE(spm_of_data); i++) {
> +		ret = of_property_read_u32(node, spm_of_data[i].key, &val);
> +		if (ret)
> +			continue;
> +		spm_dev->drv.reg_shadow[spm_of_data[i].id] = val;
> +	}
> +
> +	/* Read the byte arrays for the SPM sleep sequences */
> +	for (i = 0; i < ARRAY_SIZE(mode_of_data); i++) {
> +		modes[mode_count].start_addr = 0;
> +		key = mode_of_data[i].key;
> +		modes[mode_count].cmd =
> +			(uint8_t *)of_get_property(node, key, &val);
> +		if (!modes[mode_count].cmd)
> +			continue;
> +		modes[mode_count].mode = mode_of_data[i].id;
> +		mode_count++;
> +	}
> +
> +	spm_dev->drv.modes = devm_kcalloc(&pdev->dev, mode_count,
> +						sizeof(modes[0]), GFP_KERNEL);
> +	if (!spm_dev->drv.modes)
> +		return -ENOMEM;
> +	spm_dev->drv.num_modes = mode_count;
> +	memcpy(spm_dev->drv.modes, &modes[0], sizeof(modes[0]) * mode_count);
> +
> +	/* Initialize the hardware */
> +	ret = msm_spm_drv_init(&spm_dev->drv);
> +	if (ret) {
> +		kfree(spm_dev->drv.modes);
> +		return ret;
> +	}
> +
> +	spm_dev->initialized = true;
> +	return ret;
> +
> +fail:
> +	dev_err(&pdev->dev, "SPM device probe failed: %d\n", ret);
> +	return ret;
> +}
> +
> +static struct of_device_id msm_spm_match_table[] = {

const.


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