[v8,1/7] qcom: spm: Add Subsystem Power Manager driver

Message ID 1412718106-17049-2-git-send-email-lina.iyer@linaro.org
State New
Headers show

Commit Message

Lina Iyer Oct. 7, 2014, 9:41 p.m.
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.

Based on work by: Mahesh Sivasubramanian <msivasub@codeaurora.org>,
Ai Li <ali@codeaurora.org>, Praveen Chidambaram <pchidamb@codeaurora.org>
Original tree available at -
git://codeaurora.org/quic/la/kernel/msm-3.10.git

Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 .../devicetree/bindings/arm/msm/qcom,saw2.txt      |  31 ++-
 drivers/soc/qcom/Kconfig                           |   8 +
 drivers/soc/qcom/Makefile                          |   1 +
 drivers/soc/qcom/spm.c                             | 223 +++++++++++++++++++++
 4 files changed, 257 insertions(+), 6 deletions(-)
 create mode 100644 drivers/soc/qcom/spm.c

Comments

Stephen Boyd Oct. 9, 2014, 1:12 a.m. | #1
On 10/07/2014 02:41 PM, Lina Iyer wrote:
> diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt b/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt
> index 1505fb8..a18e8fc 100644
> --- a/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt
> +++ b/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt
> @@ -2,11 +2,20 @@ SPM AVS Wrapper 2 (SAW2)
>   
>   The SAW2 is a wrapper around the Subsystem Power Manager (SPM) and the
>   Adaptive Voltage Scaling (AVS) hardware. The SPM is a programmable
> -micro-controller that transitions a piece of hardware (like a processor or
> +power-controller that transitions a piece of hardware (like a processor or
>   subsystem) into and out of low power modes via a direct connection to
>   the PMIC. It can also be wired up to interact with other processors in the
>   system, notifying them when a low power state is entered or exited.
>   
> +Multiple revisions of the SAW hardware is supported using these Device Nodes.

s/is/are/

> +SAW2 revisions differ in the register offset and configuration data. Also,
> +same revision of the SAW in different SoCs may have different configuration

the same

> +data due the the differences in hardware capabilities. Hence the SoC name, the
> +version of the SAW hardware in that SoC and the distinction between cpu (big
> +or Little) or cache, may be needed to uniquely identify the SAW register
> +configuration and initialization data. The compatible string is used to
> +indicate this parameter.
> +
>   PROPERTIES
>   
>   - compatible:
> 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..c1dd04b
> --- /dev/null
> +++ b/drivers/soc/qcom/spm.c
> @@ -0,0 +1,223 @@
> +/* 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/pm.h>
> +
> +#define MAX_PMIC_DATA 3
> +#define MAX_SEQ_DATA 64
> +
> +enum {
> +	SPM_REG_CFG,
> +	SPM_REG_SPM_CTL,
> +	SPM_REG_DLY,
> +	SPM_REG_PMIC_DLY,
> +	SPM_REG_PMIC_DATA_0,
> +	SPM_REG_VCTL,
> +	SPM_REG_SEQ_ENTRY,
> +	SPM_REG_SPM_STS,
> +	SPM_REG_PMIC_STS,
> +	SPM_REG_NR,
> +};
> +
> +struct spm_reg_data {
> +	/* Register position */
> +	const u8 *reg_offset;
> +
> +	/* Register initialization values */
> +	u32 spm_cfg;
> +	u32 spm_dly;
> +	u32 pmic_dly;
> +	u32 pmic_data[MAX_PMIC_DATA];
> +
> +	/* Sequences and start indices */
> +	u8 seq[MAX_SEQ_DATA];
> +	u8 start_index[PM_SLEEP_MODE_NR];
> +
> +};
> +
> +struct spm_driver_data {
> +	void __iomem *reg_base_addr;

It's not really an address, more like a reg_base or just base.

> +	const struct spm_reg_data *reg_data;
> +};
> +
> +static const u8 spm_reg_offset_v2_1[SPM_REG_NR] = {
> +	[SPM_REG_CFG]		= 0x08,
> +	[SPM_REG_SPM_CTL]	= 0x30,
> +	[SPM_REG_DLY]		= 0x34,
> +	[SPM_REG_SEQ_ENTRY]	= 0x80,
> +};
> +
> +/* SPM register data for 8974, 8084 */
> +static const struct spm_reg_data spm_reg_8974_8084_cpu  = {
> +	.reg_offset = spm_reg_offset_v2_1,
> +	.spm_cfg = 0x1,
> +	.spm_dly = 0x3C102800,
> +	.seq = { 0x03, 0x0B, 0x0F, 0x00, 0x20, 0x80, 0x10, 0xE8, 0x5B, 0x03,
> +		0x3B, 0xE8, 0x5B, 0x82, 0x10, 0x0B, 0x30, 0x06, 0x26, 0x30,
> +		0x0F },
> +	.start_index[PM_SLEEP_MODE_STBY] = 0,
> +	.start_index[PM_SLEEP_MODE_SPC] = 3,
> +};
> +
> +static DEFINE_PER_CPU_SHARED_ALIGNED(struct spm_driver_data, cpu_spm_drv);
> +
> +/**
> + * spm_set_low_power_mode() - Configure SPM start address for low power mode
> + * @mode: SPM LPM mode to enter
> + */
> +int qcom_spm_set_low_power_mode(enum pm_sleep_mode mode)
> +{
> +	struct spm_driver_data *drv = &__get_cpu_var(cpu_spm_drv);

this_cpu_ptr()

> +	u32 start_index;
> +	u32 ctl_val;
> +
> +	if (!drv->reg_base_addr)
> +		return -ENXIO;
> +
> +	start_index = drv->reg_data->start_index[mode];
> +
> +	ctl_val = readl_relaxed(drv->reg_base_addr +
> +				drv->reg_data->reg_offset[SPM_REG_SPM_CTL]);
> +	start_index &= 0x7F;

Why are we statically defining numbers larger than 0x7f? Drop this?

> +	start_index <<= 4;
> +	ctl_val &= 0xFFFFF80F;

Make a #define for this register field (or two)?

#define SPM_CTL_INDEX 0x7f
#define SPM_CTL_INDEX_SHIFT 4
#define SPM_CTL_EN BIT(0)

ctl_val &= ~(SPM_CTL_INDEX << SPM_CTL_INDEX_SHIFT);
ctl_val |= start_index << SPM_CTL_INDEX_SHIFT;
ctl_val |= SPM_CTL_EN;

> +	ctl_val |= start_index;
> +	ctl_val |= 0x1; /* Enable the SPM CTL register */
> +	writel_relaxed(ctl_val, drv->reg_base_addr +
> +				drv->reg_data->reg_offset[SPM_REG_SPM_CTL]);

Can we please have spm_read/write functions that take the drv, register 
mapping enum, and optional value?

> +	/* Ensure we have written the start address */
> +	wmb();
> +
> +	return 0;
> +}
> +
> +static struct spm_driver_data *spm_get_drv(struct platform_device *pdev)
> +{
> +	struct spm_driver_data *drv = NULL;
> +	struct device_node *cpu_node, *saw_node;
> +	u32 cpu;

int instead of u32

> +
> +	for_each_possible_cpu(cpu) {
> +		if (drv)
> +			break;

This looks weird. Why not put this at the end of the loop?

> +		cpu_node = of_get_cpu_node(cpu, NULL);
> +		if (!cpu_node)
> +			continue;
> +		saw_node = of_parse_phandle(cpu_node, "qcom,saw", 0);
> +		if (saw_node) {
> +			if (saw_node == pdev->dev.of_node)
> +				drv = &per_cpu(cpu_spm_drv, cpu);

How does this work with the logical cpu map? cpu0 in hardware may be 
cpu1 in software for example.

> +			of_node_put(saw_node);
> +		}
> +		of_node_put(cpu_node);
> +	}
> +
> +	return drv;
> +}
> +
> +static const struct of_device_id spm_match_table[] = {
> +	{ .compatible = "qcom,msm8974-saw2-v2.1-cpu",
> +	  .data = &spm_reg_8974_8084_cpu },
> +	{ .compatible = "qcom,apq8084-saw2-v2.1-cpu",
> +	  .data = &spm_reg_8974_8084_cpu },
> +	{ },
> +};
> +
> +static int spm_dev_probe(struct platform_device *pdev)
> +{
> +	struct spm_driver_data *drv;
> +	struct resource *res;
> +	const struct of_device_id *match_id;
> +	void __iomem *addr, *reg_base;
> +	int i;
> +	const u32 *seq_regs;
> +
> +	 /* Get the right SPM device */
> +	drv = spm_get_drv(pdev);
> +	if (!drv)
> +		return -EINVAL;
> +
> +	/* Get the SPM start address */
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	reg_base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(reg_base))
> +		return PTR_ERR(reg_base);
> +
> +	match_id = of_match_node(spm_match_table, pdev->dev.of_node);
> +	if (!match_id)
> +		return -ENODEV;
> +
> +	/* Get the SPM register data for this instance */

The above three comments seem so obvious. Why do we need them?

> +	drv->reg_data = match_id->data;
> +	if (!drv->reg_data)
> +		return -EINVAL;
> +
> +	/* Write the SPM sequences */
> +	addr = reg_base + drv->reg_data->reg_offset[SPM_REG_SEQ_ENTRY];
> +	seq_regs = (const u32 *)drv->reg_data->seq;
> +	for (i = 0; i < ARRAY_SIZE(drv->reg_data->seq)/4; i++)
> +		writel_relaxed(seq_regs[i], 4 * i + addr);

Just use __iowrite32_copy()? Please run sparse, seq_regs is not an 
__iomem pointer.

> +
> +	/**
> +	 *  Write the SPM registers.
> +	 *  An offset of 0, indicates that the SPM version does not support
> +	 *  this register, otherwise it should be supported.
> +	 */
> +	writel_relaxed(drv->reg_data->spm_cfg,
> +			reg_base + drv->reg_data->reg_offset[SPM_REG_CFG]);
> +
> +	if (drv->reg_data->reg_offset[SPM_REG_DLY])

Is this ever false? I thought we always had these registers to configure.

> +		writel_relaxed(drv->reg_data->spm_dly, reg_base +
> +				drv->reg_data->reg_offset[SPM_REG_DLY]);
> +
> +	if (drv->reg_data->reg_offset[SPM_REG_PMIC_DLY])

Same comment.

> +		writel_relaxed(drv->reg_data->pmic_dly, reg_base +
> +				drv->reg_data->reg_offset[SPM_REG_PMIC_DLY]);
> +
> +	/* Write the PMIC data */
> +	if (drv->reg_data->reg_offset[SPM_REG_PMIC_DATA_0])
> +		for (i = 0; i < MAX_PMIC_DATA; i++)
> +			writel_relaxed(drv->reg_data->pmic_data[i], reg_base +
> +				drv->reg_data->reg_offset[SPM_REG_PMIC_DATA_0] +
> +				4 * i);

This looks unused. I'm not sure we even want to do it though? Would it 
be better if we wrote these registers in the SMP boot code with whatever 
value we're using to boot secondary CPUs? That way we don't have a 
dependency between the SMP code and this code to know to use the same 
values. We should also think about moving that SMP boot code into this 
file so that such dependencies are implicit.
Lina Iyer Oct. 9, 2014, 4:18 p.m. | #2
On Wed, Oct 08 2014 at 19:12 -0600, Stephen Boyd wrote:
>On 10/07/2014 02:41 PM, Lina Iyer wrote:
>>diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt b/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt
>>index 1505fb8..a18e8fc 100644
>>--- a/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt
>>+++ b/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt
>>@@ -2,11 +2,20 @@ SPM AVS Wrapper 2 (SAW2)
>>  The SAW2 is a wrapper around the Subsystem Power Manager (SPM) and the
>>  Adaptive Voltage Scaling (AVS) hardware. The SPM is a programmable
>>-micro-controller that transitions a piece of hardware (like a processor or
>>+power-controller that transitions a piece of hardware (like a processor or
>>  subsystem) into and out of low power modes via a direct connection to
>>  the PMIC. It can also be wired up to interact with other processors in the
>>  system, notifying them when a low power state is entered or exited.
>>+Multiple revisions of the SAW hardware is supported using these Device Nodes.
>
>s/is/are/
>
>>+SAW2 revisions differ in the register offset and configuration data. Also,
>>+same revision of the SAW in different SoCs may have different configuration
>
>the same
>
Will fix.

>+
>>+struct spm_driver_data {
>>+	void __iomem *reg_base_addr;
>
>It's not really an address, more like a reg_base or just base.
>
Sure.

>+ */
>>+int qcom_spm_set_low_power_mode(enum pm_sleep_mode mode)
>>+{
>>+	struct spm_driver_data *drv = &__get_cpu_var(cpu_spm_drv);
>
>this_cpu_ptr()
>
OK.
>>+	u32 start_index;
>>+	u32 ctl_val;
>>+
>>+	if (!drv->reg_base_addr)
>>+		return -ENXIO;
>>+
>>+	start_index = drv->reg_data->start_index[mode];
>>+
>>+	ctl_val = readl_relaxed(drv->reg_base_addr +
>>+				drv->reg_data->reg_offset[SPM_REG_SPM_CTL]);
>>+	start_index &= 0x7F;
>
>Why are we statically defining numbers larger than 0x7f? Drop this?
>
OK
>>+	start_index <<= 4;
>>+	ctl_val &= 0xFFFFF80F;
>
>Make a #define for this register field (or two)?
>
>#define SPM_CTL_INDEX 0x7f
>#define SPM_CTL_INDEX_SHIFT 4
>#define SPM_CTL_EN BIT(0)
>
>ctl_val &= ~(SPM_CTL_INDEX << SPM_CTL_INDEX_SHIFT);
>ctl_val |= start_index << SPM_CTL_INDEX_SHIFT;
>ctl_val |= SPM_CTL_EN;
>
Not liking all these macros, that would be used one time. But sure.

>>+	ctl_val |= start_index;
>>+	ctl_val |= 0x1; /* Enable the SPM CTL register */
>>+	writel_relaxed(ctl_val, drv->reg_base_addr +
>>+				drv->reg_data->reg_offset[SPM_REG_SPM_CTL]);
>
>Can we please have spm_read/write functions that take the drv, 
>register mapping enum, and optional value?
>
OK.

>>+	/* Ensure we have written the start address */
>>+	wmb();
>>+
>>+	return 0;
>>+}
>>+
>>+static struct spm_driver_data *spm_get_drv(struct platform_device *pdev)
>>+{
>>+	struct spm_driver_data *drv = NULL;
>>+	struct device_node *cpu_node, *saw_node;
>>+	u32 cpu;
>
>int instead of u32
>
>>+
>>+	for_each_possible_cpu(cpu) {
>>+		if (drv)
>>+			break;
>
>This looks weird. Why not put this at the end of the loop?
>
Yeah.. Not sure what I was thinking, seemed like a good idea at that time :(
Will change.

>>+		cpu_node = of_get_cpu_node(cpu, NULL);
>>+		if (!cpu_node)
>>+			continue;
>>+		saw_node = of_parse_phandle(cpu_node, "qcom,saw", 0);
>>+		if (saw_node) {
>>+			if (saw_node == pdev->dev.of_node)
>>+				drv = &per_cpu(cpu_spm_drv, cpu);
>
>How does this work with the logical cpu map? cpu0 in hardware may be 
>cpu1 in software for example.
>
As long as the DT link to the right cpu is correct, we should be fine.
No?

>+
>>+	/* Get the SPM register data for this instance */
>
>The above three comments seem so obvious. Why do we need them?
>
>>+	drv->reg_data = match_id->data;
>>+	if (!drv->reg_data)
>>+		return -EINVAL;
>>+
>>+	/* Write the SPM sequences */
>>+	addr = reg_base + drv->reg_data->reg_offset[SPM_REG_SEQ_ENTRY];
>>+	seq_regs = (const u32 *)drv->reg_data->seq;
>>+	for (i = 0; i < ARRAY_SIZE(drv->reg_data->seq)/4; i++)
>>+		writel_relaxed(seq_regs[i], 4 * i + addr);
>
>Just use __iowrite32_copy()? Please run sparse, seq_regs is not an 
>__iomem pointer.
>
OK
>>+
>>+	/**
>>+	 *  Write the SPM registers.
>>+	 *  An offset of 0, indicates that the SPM version does not support
>>+	 *  this register, otherwise it should be supported.
>>+	 */
>>+	writel_relaxed(drv->reg_data->spm_cfg,
>>+			reg_base + drv->reg_data->reg_offset[SPM_REG_CFG]);
>>+
>>+	if (drv->reg_data->reg_offset[SPM_REG_DLY])
>
>Is this ever false? I thought we always had these registers to configure.
>
Probably not, but in the version 1.1 of SAW2 does not configure this
register, so we dont have to and let it be in its default.

>>+		writel_relaxed(drv->reg_data->spm_dly, reg_base +
>>+				drv->reg_data->reg_offset[SPM_REG_DLY]);
>>+
>>+	if (drv->reg_data->reg_offset[SPM_REG_PMIC_DLY])
>
>Same comment.
>
>>+		writel_relaxed(drv->reg_data->pmic_dly, reg_base +
>>+				drv->reg_data->reg_offset[SPM_REG_PMIC_DLY]);
>>+
>>+	/* Write the PMIC data */
>>+	if (drv->reg_data->reg_offset[SPM_REG_PMIC_DATA_0])
>>+		for (i = 0; i < MAX_PMIC_DATA; i++)
>>+			writel_relaxed(drv->reg_data->pmic_data[i], reg_base +
>>+				drv->reg_data->reg_offset[SPM_REG_PMIC_DATA_0] +
>>+				4 * i);
>
>This looks unused. I'm not sure we even want to do it though? Would it 
>be better if we wrote these registers in the SMP boot code with 
>whatever value we're using to boot secondary CPUs? That way we don't 
>have a dependency between the SMP code and this code to know to use 
>the same values. 
No, no, these are the registers that we need to bring the core out of
Standalone PC. When I add voltage control to SPM, this register will be
modified in this driver too. One of the voltage would be active votlage
and that would shadow the running voltage for the core.

>
>We should also think about moving that SMP boot code 
>into this file so that such dependencies are implicit.
Not sure, we need this register for SMP boot. But I will be open to
your ideas in this regard.
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Sudeep Holla Oct. 9, 2014, 4:53 p.m. | #3
On 07/10/14 22:41, Lina Iyer wrote:
> 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.
>
> Based on work by: Mahesh Sivasubramanian <msivasub@codeaurora.org>,
> Ai Li <ali@codeaurora.org>, Praveen Chidambaram <pchidamb@codeaurora.org>
> Original tree available at -
> git://codeaurora.org/quic/la/kernel/msm-3.10.git
>
> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
> ---
>   .../devicetree/bindings/arm/msm/qcom,saw2.txt      |  31 ++-
>   drivers/soc/qcom/Kconfig                           |   8 +
>   drivers/soc/qcom/Makefile                          |   1 +
>   drivers/soc/qcom/spm.c                             | 223 +++++++++++++++++++++
>   4 files changed, 257 insertions(+), 6 deletions(-)
>   create mode 100644 drivers/soc/qcom/spm.c
>

[...]

> +
> +static struct spm_driver_data *spm_get_drv(struct platform_device *pdev)
> +{
> +       struct spm_driver_data *drv = NULL;
> +       struct device_node *cpu_node, *saw_node;
> +       u32 cpu;
> +
> +       for_each_possible_cpu(cpu) {
> +               if (drv)
> +                       break;
> +               cpu_node = of_get_cpu_node(cpu, NULL);

I have not looked at the patch in detail, just this caught my attention
as I removed most of these unnecessary parsing in ARM code. Unless you
need this before topology_init, you need not parse DT to get cpu_node.
You can use of_cpu_device_node_get instead.

Regards,
Sudeep

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Lina Iyer Oct. 9, 2014, 5:12 p.m. | #4
On Thu, Oct 09 2014 at 10:53 -0600, Sudeep Holla wrote:
>
>
>On 07/10/14 22:41, Lina Iyer wrote:
>>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.
>>
>>Based on work by: Mahesh Sivasubramanian <msivasub@codeaurora.org>,
>>Ai Li <ali@codeaurora.org>, Praveen Chidambaram <pchidamb@codeaurora.org>
>>Original tree available at -
>>git://codeaurora.org/quic/la/kernel/msm-3.10.git
>>
>>Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
>>---
>>  .../devicetree/bindings/arm/msm/qcom,saw2.txt      |  31 ++-
>>  drivers/soc/qcom/Kconfig                           |   8 +
>>  drivers/soc/qcom/Makefile                          |   1 +
>>  drivers/soc/qcom/spm.c                             | 223 +++++++++++++++++++++
>>  4 files changed, 257 insertions(+), 6 deletions(-)
>>  create mode 100644 drivers/soc/qcom/spm.c
>>
>
>[...]
>
>>+
>>+static struct spm_driver_data *spm_get_drv(struct platform_device *pdev)
>>+{
>>+       struct spm_driver_data *drv = NULL;
>>+       struct device_node *cpu_node, *saw_node;
>>+       u32 cpu;
>>+
>>+       for_each_possible_cpu(cpu) {
>>+               if (drv)
>>+                       break;
>>+               cpu_node = of_get_cpu_node(cpu, NULL);
>
>I have not looked at the patch in detail, just this caught my attention
>as I removed most of these unnecessary parsing in ARM code. Unless you
>need this before topology_init, you need not parse DT to get cpu_node.
>You can use of_cpu_device_node_get instead.
Thanks. But in this usecase, I may need to iterate through all possible
cpus and do a get of the cpu and then get the SAW instance from that and
compare against the SPM instance that is being probed.
SPM does not have a reference to the CPU.
>
>Regards,
>Sudeep
>
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Sudeep Holla Oct. 9, 2014, 5:23 p.m. | #5
On 09/10/14 18:12, Lina Iyer wrote:
> On Thu, Oct 09 2014 at 10:53 -0600, Sudeep Holla wrote:
>>
>>
>> On 07/10/14 22:41, Lina Iyer wrote:
>>> 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.
>>>
>>> Based on work by: Mahesh Sivasubramanian <msivasub@codeaurora.org>,
>>> Ai Li <ali@codeaurora.org>, Praveen Chidambaram <pchidamb@codeaurora.org>
>>> Original tree available at -
>>> git://codeaurora.org/quic/la/kernel/msm-3.10.git
>>>
>>> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
>>> ---
>>>   .../devicetree/bindings/arm/msm/qcom,saw2.txt      |  31 ++-
>>>   drivers/soc/qcom/Kconfig                           |   8 +
>>>   drivers/soc/qcom/Makefile                          |   1 +
>>>   drivers/soc/qcom/spm.c                             | 223 +++++++++++++++++++++
>>>   4 files changed, 257 insertions(+), 6 deletions(-)
>>>   create mode 100644 drivers/soc/qcom/spm.c
>>>
>>
>> [...]
>>
>>> +
>>> +static struct spm_driver_data *spm_get_drv(struct platform_device *pdev)
>>> +{
>>> +       struct spm_driver_data *drv = NULL;
>>> +       struct device_node *cpu_node, *saw_node;
>>> +       u32 cpu;
>>> +
>>> +       for_each_possible_cpu(cpu) {
>>> +               if (drv)
>>> +                       break;
>>> +               cpu_node = of_get_cpu_node(cpu, NULL);
>>
>> I have not looked at the patch in detail, just this caught my attention
>> as I removed most of these unnecessary parsing in ARM code. Unless you
>> need this before topology_init, you need not parse DT to get cpu_node.
>> You can use of_cpu_device_node_get instead.
> Thanks. But in this usecase, I may need to iterate through all possible
> cpus and do a get of the cpu and then get the SAW instance from that and
> compare against the SPM instance that is being probed.
> SPM does not have a reference to the CPU.

No that shouldn't matter. If spm_get_drv is called after topology_init 
(which if IIRC is subsys_initcall), then what I meant is you need not
parse DT(via of_get_cpu_node) instead fetch the stashed cpu_node using
of_cpu_device_node_get(cpu_num)

Regards,
Sudeep

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Lina Iyer Oct. 9, 2014, 5:25 p.m. | #6
On Thu, Oct 09 2014 at 11:23 -0600, Sudeep Holla wrote:
>
>
>On 09/10/14 18:12, Lina Iyer wrote:
>>On Thu, Oct 09 2014 at 10:53 -0600, Sudeep Holla wrote:
>>>
>>>
>>>On 07/10/14 22:41, Lina Iyer wrote:
>>>>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.
>>>>
>>>>Based on work by: Mahesh Sivasubramanian <msivasub@codeaurora.org>,
>>>>Ai Li <ali@codeaurora.org>, Praveen Chidambaram <pchidamb@codeaurora.org>
>>>>Original tree available at -
>>>>git://codeaurora.org/quic/la/kernel/msm-3.10.git
>>>>
>>>>Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
>>>>---
>>>>  .../devicetree/bindings/arm/msm/qcom,saw2.txt      |  31 ++-
>>>>  drivers/soc/qcom/Kconfig                           |   8 +
>>>>  drivers/soc/qcom/Makefile                          |   1 +
>>>>  drivers/soc/qcom/spm.c                             | 223 +++++++++++++++++++++
>>>>  4 files changed, 257 insertions(+), 6 deletions(-)
>>>>  create mode 100644 drivers/soc/qcom/spm.c
>>>>
>>>
>>>[...]
>>>
>>>>+
>>>>+static struct spm_driver_data *spm_get_drv(struct platform_device *pdev)
>>>>+{
>>>>+       struct spm_driver_data *drv = NULL;
>>>>+       struct device_node *cpu_node, *saw_node;
>>>>+       u32 cpu;
>>>>+
>>>>+       for_each_possible_cpu(cpu) {
>>>>+               if (drv)
>>>>+                       break;
>>>>+               cpu_node = of_get_cpu_node(cpu, NULL);
>>>
>>>I have not looked at the patch in detail, just this caught my attention
>>>as I removed most of these unnecessary parsing in ARM code. Unless you
>>>need this before topology_init, you need not parse DT to get cpu_node.
>>>You can use of_cpu_device_node_get instead.
>>Thanks. But in this usecase, I may need to iterate through all possible
>>cpus and do a get of the cpu and then get the SAW instance from that and
>>compare against the SPM instance that is being probed.
>>SPM does not have a reference to the CPU.
>
>No that shouldn't matter. If spm_get_drv is called after topology_init 
>(which if IIRC is subsys_initcall), then what I meant is you need not
>parse DT(via of_get_cpu_node) instead fetch the stashed cpu_node using
>of_cpu_device_node_get(cpu_num)
Ah, Ok. 
>
>Regards,
>Sudeep
>
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Stephen Boyd Oct. 9, 2014, 8:20 p.m. | #7
On 10/09, Lina Iyer wrote:
> On Wed, Oct 08 2014 at 19:12 -0600, Stephen Boyd wrote:
> >On 10/07/2014 02:41 PM, Lina Iyer wrote:
> >>+		cpu_node = of_get_cpu_node(cpu, NULL);
> >>+		if (!cpu_node)
> >>+			continue;
> >>+		saw_node = of_parse_phandle(cpu_node, "qcom,saw", 0);
> >>+		if (saw_node) {
> >>+			if (saw_node == pdev->dev.of_node)
> >>+				drv = &per_cpu(cpu_spm_drv, cpu);
> >
> >How does this work with the logical cpu map? cpu0 in hardware may
> >be cpu1 in software for example.
> >
> As long as the DT link to the right cpu is correct, we should be fine.
> No?

Yes I was worried we wanted to know the physical CPU for some
reason. As long as everything is logical then we're good.

> >>+		writel_relaxed(drv->reg_data->pmic_dly, reg_base +
> >>+				drv->reg_data->reg_offset[SPM_REG_PMIC_DLY]);
> >>+
> >>+	/* Write the PMIC data */
> >>+	if (drv->reg_data->reg_offset[SPM_REG_PMIC_DATA_0])
> >>+		for (i = 0; i < MAX_PMIC_DATA; i++)
> >>+			writel_relaxed(drv->reg_data->pmic_data[i], reg_base +
> >>+				drv->reg_data->reg_offset[SPM_REG_PMIC_DATA_0] +
> >>+				4 * i);
> >
> >This looks unused. I'm not sure we even want to do it though?
> >Would it be better if we wrote these registers in the SMP boot
> >code with whatever value we're using to boot secondary CPUs? That
> >way we don't have a dependency between the SMP code and this code
> >to know to use the same values.
> No, no, these are the registers that we need to bring the core out of
> Standalone PC. When I add voltage control to SPM, this register will be
> modified in this driver too. One of the voltage would be active votlage
> and that would shadow the running voltage for the core.

Right and the SMP boot code sets that initial voltage, hence the
dependency we could try to avoid. If the SMP boot code just wrote
this register as well with whatever it set the voltage to then we
don't need to do it again here.

> 
> >
> >We should also think about moving that SMP boot code into this
> >file so that such dependencies are implicit.
> Not sure, we need this register for SMP boot. But I will be open to
> your ideas in this regard.

Otherwise we move that SMP boot code into this file so that we
can share the initial voltage with this driver via some private
per-cpu variable or something. Or we just ignore this whole thing
and just leave it hardcoded to match the SMP boot code.

Patch

diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt b/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt
index 1505fb8..a18e8fc 100644
--- a/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt
+++ b/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt
@@ -2,11 +2,20 @@  SPM AVS Wrapper 2 (SAW2)
 
 The SAW2 is a wrapper around the Subsystem Power Manager (SPM) and the
 Adaptive Voltage Scaling (AVS) hardware. The SPM is a programmable
-micro-controller that transitions a piece of hardware (like a processor or
+power-controller that transitions a piece of hardware (like a processor or
 subsystem) into and out of low power modes via a direct connection to
 the PMIC. It can also be wired up to interact with other processors in the
 system, notifying them when a low power state is entered or exited.
 
+Multiple revisions of the SAW hardware is supported using these Device Nodes.
+SAW2 revisions differ in the register offset and configuration data. Also,
+same revision of the SAW in different SoCs may have different configuration
+data due the the differences in hardware capabilities. Hence the SoC name, the
+version of the SAW hardware in that SoC and the distinction between cpu (big
+or Little) or cache, may be needed to uniquely identify the SAW register
+configuration and initialization data. The compatible string is used to
+indicate this parameter.
+
 PROPERTIES
 
 - compatible:
@@ -14,10 +23,13 @@  PROPERTIES
 	Value type: <string>
 	Definition: shall contain "qcom,saw2". A more specific value should be
 		    one of:
-			 "qcom,saw2-v1"
-			 "qcom,saw2-v1.1"
-			 "qcom,saw2-v2"
-			 "qcom,saw2-v2.1"
+			"qcom,saw2-v1"
+			"qcom,saw2-v1.1"
+			"qcom,saw2-v2"
+			"qcom,saw2-v2.1"
+			"qcom,apq8064-saw2-v1.1-cpu"
+			"qcom,msm8974-saw2-v2.1-cpu"
+			"qcom,apq8084-saw2-v2.1-cpu"
 
 - reg:
 	Usage: required
@@ -26,10 +38,17 @@  PROPERTIES
 		    the register region. An optional second element specifies
 		    the base address and size of the alias register region.
 
+- regulator:
+	Usage: optional
+	Value type: boolean
+	Definition: Indicates that this SPM device acts as a regulator device
+			device for the core (CPU or Cache) the SPM is attached
+			to.
 
 Example:
 
-	regulator@2099000 {
+	power-controller@2099000 {
 		compatible = "qcom,saw2";
 		reg = <0x02099000 0x1000>, <0x02009000 0x1000>;
+		regulator;
 	};
diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 7dcd554..012fb37 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 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..c1dd04b
--- /dev/null
+++ b/drivers/soc/qcom/spm.c
@@ -0,0 +1,223 @@ 
+/* 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/pm.h>
+
+#define MAX_PMIC_DATA 3
+#define MAX_SEQ_DATA 64
+
+enum {
+	SPM_REG_CFG,
+	SPM_REG_SPM_CTL,
+	SPM_REG_DLY,
+	SPM_REG_PMIC_DLY,
+	SPM_REG_PMIC_DATA_0,
+	SPM_REG_VCTL,
+	SPM_REG_SEQ_ENTRY,
+	SPM_REG_SPM_STS,
+	SPM_REG_PMIC_STS,
+	SPM_REG_NR,
+};
+
+struct spm_reg_data {
+	/* Register position */
+	const u8 *reg_offset;
+
+	/* Register initialization values */
+	u32 spm_cfg;
+	u32 spm_dly;
+	u32 pmic_dly;
+	u32 pmic_data[MAX_PMIC_DATA];
+
+	/* Sequences and start indices */
+	u8 seq[MAX_SEQ_DATA];
+	u8 start_index[PM_SLEEP_MODE_NR];
+
+};
+
+struct spm_driver_data {
+	void __iomem *reg_base_addr;
+	const struct spm_reg_data *reg_data;
+};
+
+static const u8 spm_reg_offset_v2_1[SPM_REG_NR] = {
+	[SPM_REG_CFG]		= 0x08,
+	[SPM_REG_SPM_CTL]	= 0x30,
+	[SPM_REG_DLY]		= 0x34,
+	[SPM_REG_SEQ_ENTRY]	= 0x80,
+};
+
+/* SPM register data for 8974, 8084 */
+static const struct spm_reg_data spm_reg_8974_8084_cpu  = {
+	.reg_offset = spm_reg_offset_v2_1,
+	.spm_cfg = 0x1,
+	.spm_dly = 0x3C102800,
+	.seq = { 0x03, 0x0B, 0x0F, 0x00, 0x20, 0x80, 0x10, 0xE8, 0x5B, 0x03,
+		0x3B, 0xE8, 0x5B, 0x82, 0x10, 0x0B, 0x30, 0x06, 0x26, 0x30,
+		0x0F },
+	.start_index[PM_SLEEP_MODE_STBY] = 0,
+	.start_index[PM_SLEEP_MODE_SPC] = 3,
+};
+
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct spm_driver_data, cpu_spm_drv);
+
+/**
+ * spm_set_low_power_mode() - Configure SPM start address for low power mode
+ * @mode: SPM LPM mode to enter
+ */
+int qcom_spm_set_low_power_mode(enum pm_sleep_mode mode)
+{
+	struct spm_driver_data *drv = &__get_cpu_var(cpu_spm_drv);
+	u32 start_index;
+	u32 ctl_val;
+
+	if (!drv->reg_base_addr)
+		return -ENXIO;
+
+	start_index = drv->reg_data->start_index[mode];
+
+	ctl_val = readl_relaxed(drv->reg_base_addr +
+				drv->reg_data->reg_offset[SPM_REG_SPM_CTL]);
+	start_index &= 0x7F;
+	start_index <<= 4;
+	ctl_val &= 0xFFFFF80F;
+	ctl_val |= start_index;
+	ctl_val |= 0x1; /* Enable the SPM CTL register */
+	writel_relaxed(ctl_val, drv->reg_base_addr +
+				drv->reg_data->reg_offset[SPM_REG_SPM_CTL]);
+	/* Ensure we have written the start address */
+	wmb();
+
+	return 0;
+}
+
+static struct spm_driver_data *spm_get_drv(struct platform_device *pdev)
+{
+	struct spm_driver_data *drv = NULL;
+	struct device_node *cpu_node, *saw_node;
+	u32 cpu;
+
+	for_each_possible_cpu(cpu) {
+		if (drv)
+			break;
+		cpu_node = of_get_cpu_node(cpu, NULL);
+		if (!cpu_node)
+			continue;
+		saw_node = of_parse_phandle(cpu_node, "qcom,saw", 0);
+		if (saw_node) {
+			if (saw_node == pdev->dev.of_node)
+				drv = &per_cpu(cpu_spm_drv, cpu);
+			of_node_put(saw_node);
+		}
+		of_node_put(cpu_node);
+	}
+
+	return drv;
+}
+
+static const struct of_device_id spm_match_table[] = {
+	{ .compatible = "qcom,msm8974-saw2-v2.1-cpu",
+	  .data = &spm_reg_8974_8084_cpu },
+	{ .compatible = "qcom,apq8084-saw2-v2.1-cpu",
+	  .data = &spm_reg_8974_8084_cpu },
+	{ },
+};
+
+static int spm_dev_probe(struct platform_device *pdev)
+{
+	struct spm_driver_data *drv;
+	struct resource *res;
+	const struct of_device_id *match_id;
+	void __iomem *addr, *reg_base;
+	int i;
+	const u32 *seq_regs;
+
+	 /* Get the right SPM device */
+	drv = spm_get_drv(pdev);
+	if (!drv)
+		return -EINVAL;
+
+	/* Get the SPM start address */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	reg_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(reg_base))
+		return PTR_ERR(reg_base);
+
+	match_id = of_match_node(spm_match_table, pdev->dev.of_node);
+	if (!match_id)
+		return -ENODEV;
+
+	/* Get the SPM register data for this instance */
+	drv->reg_data = match_id->data;
+	if (!drv->reg_data)
+		return -EINVAL;
+
+	/* Write the SPM sequences */
+	addr = reg_base + drv->reg_data->reg_offset[SPM_REG_SEQ_ENTRY];
+	seq_regs = (const u32 *)drv->reg_data->seq;
+	for (i = 0; i < ARRAY_SIZE(drv->reg_data->seq)/4; i++)
+		writel_relaxed(seq_regs[i], 4 * i + addr);
+
+	/**
+	 *  Write the SPM registers.
+	 *  An offset of 0, indicates that the SPM version does not support
+	 *  this register, otherwise it should be supported.
+	 */
+	writel_relaxed(drv->reg_data->spm_cfg,
+			reg_base + drv->reg_data->reg_offset[SPM_REG_CFG]);
+
+	if (drv->reg_data->reg_offset[SPM_REG_DLY])
+		writel_relaxed(drv->reg_data->spm_dly, reg_base +
+				drv->reg_data->reg_offset[SPM_REG_DLY]);
+
+	if (drv->reg_data->reg_offset[SPM_REG_PMIC_DLY])
+		writel_relaxed(drv->reg_data->pmic_dly, reg_base +
+				drv->reg_data->reg_offset[SPM_REG_PMIC_DLY]);
+
+	/* Write the PMIC data */
+	if (drv->reg_data->reg_offset[SPM_REG_PMIC_DATA_0])
+		for (i = 0; i < MAX_PMIC_DATA; i++)
+			writel_relaxed(drv->reg_data->pmic_data[i], reg_base +
+				drv->reg_data->reg_offset[SPM_REG_PMIC_DATA_0] +
+				4 * i);
+
+	/**
+	 * Ensure all observers see the above register writes before the
+	 * cpuidle driver is allowed to use the SPM.
+	 */
+	wmb();
+	drv->reg_base_addr = reg_base;
+
+	return 0;
+}
+
+static struct platform_driver spm_driver = {
+	.probe = spm_dev_probe,
+	.driver = {
+		.name = "qcom,spm",
+		.of_match_table = spm_match_table,
+	},
+};
+
+module_platform_driver(spm_driver);