Re: [PATCH v3 02/11] platform/x86/amd/pmf: Add support for PMF APCI layer

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 8/2/22 13:25, Shyam Sundar S K wrote:
> PMF driver implements the ACPI methods as defined by AMD for PMF Support.
> The ACPI layer acts as a glue that helps in providing the infrastructure
> for OEMs customization.
> 
> OEMs can refer to PMF support documentation to decide on the list of
> functions to be supported on their specific platform model.
> 
> AMD mandates that PMF ACPI fn0 and fn1 to be implemented which
> provides the set of functions, params and the notifications that
> would be sent to PMF driver so that PMF driver can adapt and
> react.
> 
> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
> ---
>  drivers/platform/x86/amd/pmf/Makefile |   2 +-
>  drivers/platform/x86/amd/pmf/acpi.c   | 153 ++++++++++++++++++++++++++
>  drivers/platform/x86/amd/pmf/core.c   |   1 +
>  drivers/platform/x86/amd/pmf/pmf.h    |  23 ++++
>  4 files changed, 178 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/platform/x86/amd/pmf/acpi.c
> 
> diff --git a/drivers/platform/x86/amd/pmf/Makefile b/drivers/platform/x86/amd/pmf/Makefile
> index 459005f659e5..2617eba773ce 100644
> --- a/drivers/platform/x86/amd/pmf/Makefile
> +++ b/drivers/platform/x86/amd/pmf/Makefile
> @@ -5,4 +5,4 @@
>  #
>  
>  obj-$(CONFIG_AMD_PMF) += amd-pmf.o
> -amd-pmf-objs := core.o
> +amd-pmf-objs := core.o acpi.o
> diff --git a/drivers/platform/x86/amd/pmf/acpi.c b/drivers/platform/x86/amd/pmf/acpi.c
> new file mode 100644
> index 000000000000..5269d48b1f5f
> --- /dev/null
> +++ b/drivers/platform/x86/amd/pmf/acpi.c
> @@ -0,0 +1,153 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * AMD Platform Management Framework Driver
> + *
> + * Copyright (c) 2022, Advanced Micro Devices, Inc.
> + * All Rights Reserved.
> + *
> + * Author: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
> + */
> +
> +#include <linux/acpi.h>
> +#include "pmf.h"
> +
> +static union acpi_object *apmf_if_call(struct amd_pmf_dev *pdev, int fn, struct acpi_buffer *param)
> +{
> +	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> +	acpi_handle ahandle = ACPI_HANDLE(pdev->dev);
> +	struct acpi_object_list apmf_if_arg_list;
> +	union acpi_object apmf_if_args[2];
> +	acpi_status status;
> +
> +	apmf_if_arg_list.count = 2;
> +	apmf_if_arg_list.pointer = &apmf_if_args[0];
> +
> +	apmf_if_args[0].type = ACPI_TYPE_INTEGER;
> +	apmf_if_args[0].integer.value = fn;
> +
> +	if (param) {
> +		apmf_if_args[1].type = ACPI_TYPE_BUFFER;
> +		apmf_if_args[1].buffer.length = param->length;
> +		apmf_if_args[1].buffer.pointer = param->pointer;
> +	} else {
> +		apmf_if_args[1].type = ACPI_TYPE_INTEGER;
> +		apmf_if_args[1].integer.value = 0;
> +	}
> +
> +	status = acpi_evaluate_object(ahandle, "APMF", &apmf_if_arg_list, &buffer);
> +	if (ACPI_FAILURE(status)) {
> +		dev_err(pdev->dev, "APMF method call failed\n");

For the next version please also log the fn variable here, so that is
clear for which call the error is happening.

> +		if (status != AE_NOT_FOUND)
> +			kfree(buffer.pointer);

buffer.pointer is initialized to NULL, so no need to check status,
just call kfree(buffer.pointer); unconditionally here.

Regards,

Hans


> +
> +		return NULL;
> +	}
> +
> +	return buffer.pointer;
> +}
> +
> +static int apmf_if_call_store_buffer(struct amd_pmf_dev *pdev, int fn, void *dest, size_t out_sz)
> +{
> +	union acpi_object *info;
> +	size_t size;
> +	int err = 0;
> +
> +	info = apmf_if_call(pdev, fn, NULL);
> +	if (!info)
> +		return -EIO;
> +
> +	if (info->type != ACPI_TYPE_BUFFER) {
> +		dev_err(pdev->dev, "object is not a buffer\n");
> +		err = -EINVAL;
> +		goto out;
> +	}
> +
> +	if (info->buffer.length < 2) {
> +		dev_err(pdev->dev, "buffer too small\n");
> +		err = -EINVAL;
> +		goto out;
> +	}
> +
> +	size = *(u16 *)info->buffer.pointer;
> +	if (info->buffer.length < size) {
> +		dev_err(pdev->dev, "buffer smaller then headersize %u < %zu\n",
> +			info->buffer.length, size);
> +		err = -EINVAL;
> +		goto out;
> +	}
> +
> +	if (size < out_sz) {
> +		dev_err(pdev->dev, "buffer too small %zu\n", size);
> +		err = -EINVAL;
> +		goto out;
> +	}
> +
> +	memcpy(dest, info->buffer.pointer, out_sz);
> +
> +out:
> +	kfree(info);
> +	return err;
> +}
> +
> +int is_apmf_func_supported(struct amd_pmf_dev *pdev, unsigned long index)
> +{
> +	/* If bit-n is set, that indicates function n+1 is supported */
> +	return !!(pdev->supported_func & BIT(index - 1));
> +}
> +
> +static int apmf_if_verify_interface(struct amd_pmf_dev *pdev)
> +{
> +	struct apmf_verify_interface output;
> +	int err;
> +
> +	err = apmf_if_call_store_buffer(pdev, APMF_FUNC_VERIFY_INTERFACE, &output, sizeof(output));
> +	if (err)
> +		return err;
> +
> +	pdev->supported_func = output.supported_functions;
> +	dev_dbg(pdev->dev, "supported functions:0x%x notifications:0x%x\n",
> +		output.supported_functions, output.notification_mask);
> +
> +	return 0;
> +}
> +
> +static int apmf_get_system_params(struct amd_pmf_dev *dev)
> +{
> +	struct apmf_system_params params;
> +	int err;
> +
> +	if (!is_apmf_func_supported(dev, APMF_FUNC_GET_SYS_PARAMS))
> +		return -EINVAL;
> +
> +	err = apmf_if_call_store_buffer(dev, APMF_FUNC_GET_SYS_PARAMS, &params, sizeof(params));
> +	if (err)
> +		return err;
> +
> +	dev_dbg(dev->dev, "system params mask:0x%x flags:0x%x cmd_code:0x%x\n",
> +		params.valid_mask,
> +		params.flags,
> +		params.command_code);
> +	params.flags = params.flags & params.valid_mask;
> +
> +	return 0;
> +}
> +
> +int apmf_acpi_init(struct amd_pmf_dev *pmf_dev)
> +{
> +	int ret;
> +
> +	ret = apmf_if_verify_interface(pmf_dev);
> +	if (ret) {
> +		dev_err(pmf_dev->dev, "APMF verify interface failed :%d\n", ret);
> +		goto out;
> +	}
> +
> +	ret = apmf_get_system_params(pmf_dev);
> +	if (ret) {
> +		dev_err(pmf_dev->dev, "APMF apmf_get_system_params failed :%d\n", ret);
> +		goto out;
> +	}
> +
> +out:
> +	return ret;
> +}
> diff --git a/drivers/platform/x86/amd/pmf/core.c b/drivers/platform/x86/amd/pmf/core.c
> index aef97965c181..c5002b7bb904 100644
> --- a/drivers/platform/x86/amd/pmf/core.c
> +++ b/drivers/platform/x86/amd/pmf/core.c
> @@ -204,6 +204,7 @@ static int amd_pmf_probe(struct platform_device *pdev)
>  	if (!dev->regbase)
>  		return -ENOMEM;
>  
> +	apmf_acpi_init(dev);
>  	platform_set_drvdata(pdev, dev);
>  
>  	mutex_init(&dev->lock);
> diff --git a/drivers/platform/x86/amd/pmf/pmf.h b/drivers/platform/x86/amd/pmf/pmf.h
> index 1c2e942e5096..bdadbff168ee 100644
> --- a/drivers/platform/x86/amd/pmf/pmf.h
> +++ b/drivers/platform/x86/amd/pmf/pmf.h
> @@ -11,6 +11,12 @@
>  #ifndef PMF_H
>  #define PMF_H
>  
> +#include <linux/acpi.h>
> +
> +/* APMF Functions */
> +#define APMF_FUNC_VERIFY_INTERFACE			0
> +#define APMF_FUNC_GET_SYS_PARAMS			1
> +
>  /* Message Definitions */
>  #define SET_SPL				0x03 /* SPL: Sustained Power Limit */
>  #define SET_SPPT			0x05 /* SPPT: Slow Package Power Tracking */
> @@ -30,6 +36,21 @@
>  #define GET_STT_LIMIT_APU	0x20
>  #define GET_STT_LIMIT_HS2	0x21
>  
> +/* AMD PMF BIOS interfaces */
> +struct apmf_verify_interface {
> +	u16 size;
> +	u16 version;
> +	u32 notification_mask;
> +	u32 supported_functions;
> +} __packed;
> +
> +struct apmf_system_params {
> +	u16 size;
> +	u32 valid_mask;
> +	u32 flags;
> +	u8 command_code;
> +} __packed;
> +
>  struct amd_pmf_dev {
>  	void __iomem *regbase;
>  	void __iomem *smu_virt_addr;
> @@ -38,9 +59,11 @@ struct amd_pmf_dev {
>  	u32 cpu_id;
>  	struct device *dev;
>  	struct mutex lock; /* protects the PMF interface */
> +	u32 supported_func;
>  };
>  
>  /* Core Layer */
> +int apmf_acpi_init(struct amd_pmf_dev *pmf_dev);
>  int amd_pmf_send_cmd(struct amd_pmf_dev *dev, u8 message, bool get, u32 arg, u32 *data);
>  
>  #endif /* PMF_H */