hwmon: (dell-smm) Use new buffer-based WMI API

Use the new buffer-based WMI API to also support ACPI firmware
implementations that do not use ACPI buffers for returning the
results of a SMM call.

Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://patch.msgid.link/20260610203453.816254-7-W_Armin@gmx.de
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index 038edffc1ac747c18ab71eb78313626f4fa13175..6ca2ea4bfe7d3acae8bf222e11fcfa4d14d1d6ac 100644 (file)
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -12,8 +12,10 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#include <linux/acpi.h>
+#include <linux/align.h>
 #include <linux/capability.h>
+#include <linux/cleanup.h>
+#include <linux/compiler_attributes.h>
 #include <linux/cpu.h>
 #include <linux/ctype.h>
 #include <linux/delay.h>
@@ -36,10 +38,10 @@
 #include <linux/thermal.h>
 #include <linux/types.h>
 #include <linux/uaccess.h>
+#include <linux/unaligned.h>
 #include <linux/wmi.h>
 
 #include <linux/i8k.h>
-#include <linux/unaligned.h>
 
 #define I8K_SMM_FN_STATUS      0x0025
 #define I8K_SMM_POWER_STATUS   0x0069
@@ -232,7 +234,7 @@ static const struct dell_smm_ops i8k_smm_ops = {
 /*
  * Call the System Management Mode BIOS over WMI.
  */
-static ssize_t wmi_parse_register(u8 *buffer, u32 length, unsigned int *reg)
+static ssize_t wmi_parse_register(u8 *buffer, size_t length, unsigned int *reg)
 {
        __le32 value;
        u32 reg_size;
@@ -253,7 +255,7 @@ static ssize_t wmi_parse_register(u8 *buffer, u32 length, unsigned int *reg)
        return reg_size + sizeof(reg_size);
 }
 
-static int wmi_parse_response(u8 *buffer, u32 length, struct smm_regs *regs)
+static int wmi_parse_response(u8 *buffer, size_t length, struct smm_regs *regs)
 {
        unsigned int *registers[] = {
                &regs->eax,
@@ -261,7 +263,7 @@ static int wmi_parse_response(u8 *buffer, u32 length, struct smm_regs *regs)
                &regs->ecx,
                &regs->edx
        };
-       u32 offset = 0;
+       size_t offset = 0;
        ssize_t ret;
        int i;
 
@@ -273,19 +275,16 @@ static int wmi_parse_response(u8 *buffer, u32 length, struct smm_regs *regs)
                if (ret < 0)
                        return ret;
 
-               offset += ret;
+               /* WMI aligns u32 integers on a 4 byte boundary */
+               offset = ALIGN(offset + ret, 4);
        }
 
-       if (offset != length)
-               return -ENOMSG;
-
        return 0;
 }
 
 static int wmi_smm_call(struct device *dev, struct smm_regs *regs)
 {
        struct wmi_device *wdev = container_of(dev, struct wmi_device, dev);
-       struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
        u32 wmi_payload[] = {
                sizeof(regs->eax),
                regs->eax,
@@ -296,34 +295,20 @@ static int wmi_smm_call(struct device *dev, struct smm_regs *regs)
                sizeof(regs->edx),
                regs->edx
        };
-       const struct acpi_buffer in = {
+       const struct wmi_buffer in = {
                .length = sizeof(wmi_payload),
-               .pointer = &wmi_payload,
+               .data = &wmi_payload,
        };
-       union acpi_object *obj;
-       acpi_status status;
+       struct wmi_buffer out;
        int ret;
 
-       status = wmidev_evaluate_method(wdev, 0x0, DELL_SMM_LEGACY_EXECUTE, &in, &out);
-       if (ACPI_FAILURE(status))
-               return -EIO;
-
-       obj = out.pointer;
-       if (!obj)
-               return -ENODATA;
-
-       if (obj->type != ACPI_TYPE_BUFFER) {
-               ret = -ENOMSG;
-
-               goto err_free;
-       }
-
-       ret = wmi_parse_response(obj->buffer.pointer, obj->buffer.length, regs);
+       ret = wmidev_invoke_method(wdev, 0x0, DELL_SMM_LEGACY_EXECUTE, &in, &out, sizeof(__le32));
+       if (ret < 0)
+               return ret;
 
-err_free:
-       kfree(obj);
+       u8 *response __free(kfree) = out.data;
 
-       return ret;
+       return wmi_parse_response(response, out.length, regs);
 }
 
 static int dell_smm_call(const struct dell_smm_ops *ops, struct smm_regs *regs)