On Tue, Jul 27, 2021 at 6:18 PM Srinivas Pandruvada
<srinivas.pandruvada@xxxxxxxxxxxxxxx> wrote:
>
> The current assumption that methods to read PCH FIVR attributes will
> return integer, is not correct. There is no good way to return integer
> as negative numbers are also valid.
>
> These read methods return a package of integers. The first integer returns
> status, which is 0 on success and any other value for failure. When the
> returned status is zero, then the second integer returns the actual value.
>
> This change fixes this issue by replacing acpi_evaluate_integer() with
> acpi_evaluate_object() and use acpi_extract_package() to extract results.
>
> Fixes: 2ce6324eadb01 ("ACPI: DPTF: Add PCH FIVR participant driver")
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # 5.10+
Applied as 5.14-rc material.
I'll apply the [2/2[ when this one is merged.
> ---
> drivers/acpi/dptf/dptf_pch_fivr.c | 51 ++++++++++++++++++++++++++-----
> 1 file changed, 43 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/acpi/dptf/dptf_pch_fivr.c b/drivers/acpi/dptf/dptf_pch_fivr.c
> index 5fca18296bf6..550b9081fcbc 100644
> --- a/drivers/acpi/dptf/dptf_pch_fivr.c
> +++ b/drivers/acpi/dptf/dptf_pch_fivr.c
> @@ -9,6 +9,42 @@
> #include <linux/module.h>
> #include <linux/platform_device.h>
>
> +struct pch_fivr_resp {
> + u64 status;
> + u64 result;
> +};
> +
> +static int pch_fivr_read(acpi_handle handle, char *method, struct pch_fivr_resp *fivr_resp)
> +{
> + struct acpi_buffer resp = { sizeof(struct pch_fivr_resp), fivr_resp};
> + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> + struct acpi_buffer format = { sizeof("NN"), "NN" };
> + union acpi_object *obj;
> + acpi_status status;
> + int ret = -EFAULT;
> +
> + status = acpi_evaluate_object(handle, method, NULL, &buffer);
> + if (ACPI_FAILURE(status))
> + return ret;
> +
> + obj = buffer.pointer;
> + if (!obj || obj->type != ACPI_TYPE_PACKAGE)
> + goto release_buffer;
> +
> + status = acpi_extract_package(obj, &format, &resp);
> + if (ACPI_FAILURE(status))
> + goto release_buffer;
> +
> + if (fivr_resp->status)
> + goto release_buffer;
> +
> + ret = 0;
> +
> +release_buffer:
> + kfree(buffer.pointer);
> + return ret;
> +}
> +
> /*
> * Presentation of attributes which are defined for INT1045
> * They are:
> @@ -23,15 +59,14 @@ static ssize_t name##_show(struct device *dev,\
> char *buf)\
> {\
> struct acpi_device *acpi_dev = dev_get_drvdata(dev);\
> - unsigned long long val;\
> - acpi_status status;\
> + struct pch_fivr_resp fivr_resp;\
> + int status;\
> \
> - status = acpi_evaluate_integer(acpi_dev->handle, #method,\
> - NULL, &val);\
> - if (ACPI_SUCCESS(status))\
> - return sprintf(buf, "%d\n", (int)val);\
> - else\
> - return -EINVAL;\
> + status = pch_fivr_read(acpi_dev->handle, #method, &fivr_resp);\
> + if (status)\
> + return status;\
> +\
> + return sprintf(buf, "%llu\n", fivr_resp.result);\
> }
>
> #define PCH_FIVR_STORE(name, method) \
> --
> 2.31.1
>
