X86 platform: hp-wmi Better match the HP WMI query interface

- Improve error handling, by explictly return zero for success, error otherwise
- WMI query command can have arbitrary input sized params
- WMI query command can have specific output sized params (0, 4, 128,..) byte

I like to go on here, but this is a rather intrusive change that should
be looked at first. I am sure the one or other thing can be done better or
there might be typo/bug somewhere.

This did not get any testing yet, only compile tested.

Next steps could be:
  - Eventually introduce hp_wmi_perform_{read,write}_query macros
  - Introduce new wireless query interface (0x1B)
  - more

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
CC: linux-acpi@vger.kernel.org
CC: platform-driver-x86@vger.kernel.org

diff --git a/drivers/platform/x86/hp-wmi.c b/drivers/platform/x86/hp-wmi.c
index 7ebe46f..d81f4cf 100644 (file)
--- a/drivers/platform/x86/hp-wmi.c
+++ b/drivers/platform/x86/hp-wmi.c
@@ -80,13 +80,12 @@ struct bios_args {
        u32 command;
        u32 commandtype;
        u32 datasize;
-       u32 data;
+       char *data;
 };
 
 struct bios_return {
        u32 sigpass;
        u32 return_code;
-       u32 value;
 };
 
 struct key_entry {
@@ -131,7 +130,27 @@ static struct platform_driver hp_wmi_driver = {
        .remove = hp_wmi_bios_remove,
 };
 
-static int hp_wmi_perform_query(int query, int write, int value)
+/*
+ * hp_wmi_perform_query
+ *
+ * query:      The commandtype -> What should be queried
+ * write:      The command -> 0 read, 1 write, 3 ODM specific
+ * buffer:     Buffer used as input and/or output
+ * buffersize: Size of buffer
+ *
+ * returns zero on success
+ *         an HP WMI query specific error code (which is positive)
+ *         -EINVAL if the query was not successful at all
+ *         -EINVAL if the output buffer size exceeds buffersize
+ *
+ * Note: The buffersize must at least be the maximum of the input and output
+ *       size. E.g. Battery info query (0x7) is defined to have 1 byte input
+ *       and 128 byte output. The caller would do:
+ *       buffer = kzalloc(128, GFP_KERNEL);
+ *       ret = hp_wmi_perform_query(0x7, 0, buffer, 128)
+ */
+static int hp_wmi_perform_query(int query, int write, char *buffer,
+                               int buffersize)
 {
        struct bios_return bios_return;
        acpi_status status;
@@ -140,8 +159,8 @@ static int hp_wmi_perform_query(int query, int write, int value)
                .signature = 0x55434553,
                .command = write ? 0x2 : 0x1,
                .commandtype = query,
-               .datasize = write ? 0x4 : 0,
-               .data = value,
+               .datasize = buffersize,
+               .data = buffer,
        };
        struct acpi_buffer input = { sizeof(struct bios_args), &args };
        struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
@@ -158,54 +177,90 @@ static int hp_wmi_perform_query(int query, int write, int value)
        }
 
        bios_return = *((struct bios_return *)obj->buffer.pointer);
+
+       if (bios_return.return_code) {
+               printk(KERN_WARNING PREFIX "Query %d returned %d\n", query,
+                      bios_return.return_code);
+               kfree(obj);
+               return bios_return.return_code;
+       }
+       if (obj->buffer.length - sizeof(bios_return) > buffersize) {
+               kfree(obj);
+               return -EINVAL;
+       }
+
+       memset(buffer, 0, buffersize);
+       memcpy(buffer,
+              ((char *)obj->buffer.pointer) + sizeof(struct bios_return),
+              obj->buffer.length - sizeof(bios_return));
        kfree(obj);
-       if (bios_return.return_code > 0)
-               return bios_return.return_code * -1;
-       else
-               return bios_return.value;
+       return 0;
 }
 
 static int hp_wmi_display_state(void)
 {
-       return hp_wmi_perform_query(HPWMI_DISPLAY_QUERY, 0, 0);
+       int state;
+       int ret = hp_wmi_perform_query(HPWMI_DISPLAY_QUERY, 0, (char *)&state,
+                                      sizeof(state));
+       if (ret)
+               return -EINVAL;
+       return state;
 }
 
 static int hp_wmi_hddtemp_state(void)
 {
-       return hp_wmi_perform_query(HPWMI_HDDTEMP_QUERY, 0, 0);
+       int state;
+       int ret = hp_wmi_perform_query(HPWMI_HDDTEMP_QUERY, 0, (char *)&state,
+                                      sizeof(state));
+       if (ret)
+               return -EINVAL;
+       return state;
 }
 
 static int hp_wmi_als_state(void)
 {
-       return hp_wmi_perform_query(HPWMI_ALS_QUERY, 0, 0);
+       int state;
+       int ret = hp_wmi_perform_query(HPWMI_ALS_QUERY, 0, (char *)&state,
+                                      sizeof(state));
+       if (ret)
+               return -EINVAL;
+       return state;
 }
 
 static int hp_wmi_dock_state(void)
 {
-       int ret = hp_wmi_perform_query(HPWMI_HARDWARE_QUERY, 0, 0);
+       int state;
+       int ret = hp_wmi_perform_query(HPWMI_HARDWARE_QUERY, 0, (char *)&state,
+                                      sizeof(state));
 
-       if (ret < 0)
-               return ret;
+       if (ret)
+               return -EINVAL;
 
-       return ret & 0x1;
+       return state & 0x1;
 }
 
 static int hp_wmi_tablet_state(void)
 {
-       int ret = hp_wmi_perform_query(HPWMI_HARDWARE_QUERY, 0, 0);
-
-       if (ret < 0)
+       int state;
+       int ret = hp_wmi_perform_query(HPWMI_HARDWARE_QUERY, 0, (char *)&state,
+                                      sizeof(state));
+       if (ret)
                return ret;
 
-       return (ret & 0x4) ? 1 : 0;
+       return (state & 0x4) ? 1 : 0;
 }
 
 static int hp_wmi_set_block(void *data, bool blocked)
 {
        enum hp_wmi_radio r = (enum hp_wmi_radio) data;
        int query = BIT(r + 8) | ((!blocked) << r);
+       int ret;
 
-       return hp_wmi_perform_query(HPWMI_WIRELESS_QUERY, 1, query);
+       ret = hp_wmi_perform_query(HPWMI_WIRELESS_QUERY, 1,
+                                  (char *)&query, sizeof(query));
+       if (ret)
+               return -EINVAL;
+       return 0;
 }
 
 static const struct rfkill_ops hp_wmi_rfkill_ops = {
@@ -214,8 +269,13 @@ static const struct rfkill_ops hp_wmi_rfkill_ops = {
 
 static bool hp_wmi_get_sw_state(enum hp_wmi_radio r)
 {
-       int wireless = hp_wmi_perform_query(HPWMI_WIRELESS_QUERY, 0, 0);
-       int mask = 0x200 << (r * 8);
+       int wireless;
+       int mask;
+       hp_wmi_perform_query(HPWMI_WIRELESS_QUERY, 0,
+                            (char *)&wireless, sizeof(wireless));
+       /* TBD: Pass error */
+
+       mask = 0x200 << (r * 8);
 
        if (wireless & mask)
                return false;
@@ -225,8 +285,13 @@ static bool hp_wmi_get_sw_state(enum hp_wmi_radio r)
 
 static bool hp_wmi_get_hw_state(enum hp_wmi_radio r)
 {
-       int wireless = hp_wmi_perform_query(HPWMI_WIRELESS_QUERY, 0, 0);
-       int mask = 0x800 << (r * 8);
+       int wireless;
+       int mask;
+       hp_wmi_perform_query(HPWMI_WIRELESS_QUERY, 0,
+                            (char *)&wireless, sizeof(wireless));
+       /* TBD: Pass error */
+
+       mask = 0x800 << (r * 8);
 
        if (wireless & mask)
                return false;
@@ -283,7 +348,11 @@ static ssize_t set_als(struct device *dev, struct device_attribute *attr,
                       const char *buf, size_t count)
 {
        u32 tmp = simple_strtoul(buf, NULL, 10);
-       hp_wmi_perform_query(HPWMI_ALS_QUERY, 1, tmp);
+       int ret = hp_wmi_perform_query(HPWMI_ALS_QUERY, 1, (char *)&tmp,
+                                      sizeof(tmp));
+       if (ret)
+               return -EINVAL;
+
        return count;
 }
 
@@ -353,7 +422,7 @@ static void hp_wmi_notify(u32 value, void *context)
        static struct key_entry *key;
        union acpi_object *obj;
        u32 event_id, event_data;
-       int key_code;
+       int key_code, ret;
        u32 *location;
        acpi_status status;
 
@@ -404,8 +473,11 @@ static void hp_wmi_notify(u32 value, void *context)
        case HPWMI_SMART_ADAPTER:
                break;
        case HPWMI_BEZEL_BUTTON:
-               key_code = hp_wmi_perform_query(HPWMI_HOTKEY_QUERY, 0,
-                                                0);
+               ret = hp_wmi_perform_query(HPWMI_HOTKEY_QUERY, 0,
+                                          (char *)&key_code,
+                                          sizeof(key_code));
+               if (ret)
+                       break;
                key = hp_wmi_get_entry_by_scancode(key_code);
                if (key) {
                        switch (key->type) {
@@ -503,7 +575,12 @@ static void cleanup_sysfs(struct platform_device *device)
 static int __devinit hp_wmi_bios_setup(struct platform_device *device)
 {
        int err;
-       int wireless = hp_wmi_perform_query(HPWMI_WIRELESS_QUERY, 0, 0);
+       int wireless;
+
+       err = hp_wmi_perform_query(HPWMI_WIRELESS_QUERY, 0, (char *)&wireless,
+                                  sizeof(wireless));
+       if (err)
+               return err;
 
        err = device_create_file(&device->dev, &dev_attr_display);
        if (err)