drm/radeon: gcc fixes for radeon_atombios.c

Newer versions of gcc seem to wander off into the
weeds when dealing with variable sizes arrays in
structs.  Rather than indexing the arrays, use
pointer arithmetic.

See bugs:
https://bugs.freedesktop.org/show_bug.cgi?id=66932
https://bugs.freedesktop.org/show_bug.cgi?id=66972
https://bugs.freedesktop.org/show_bug.cgi?id=66945

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 28 insertions, 14 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c
index ad913542ec1a..404e25d285ba 100644
--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -163,8 +163,8 @@ static struct radeon_i2c_bus_rec radeon_lookup_i2c_gpio(struct radeon_device *rd
                 num_indices = (size - sizeof(ATOM_COMMON_TABLE_HEADER)) /
                         sizeof(ATOM_GPIO_I2C_ASSIGMENT);
 
+                gpio = &i2c_info->asGPIO_Info[0];
                 for (i = 0; i < num_indices; i++) {
-                        gpio = &i2c_info->asGPIO_Info[i];
 
                         radeon_lookup_i2c_gpio_quirks(rdev, gpio, i);
 
@@ -172,6 +172,8 @@ static struct radeon_i2c_bus_rec radeon_lookup_i2c_gpio(struct radeon_device *rd
                                 i2c = radeon_get_bus_rec_for_i2c_gpio(gpio);
                                 break;
                         }
+                        gpio = (ATOM_GPIO_I2C_ASSIGMENT *)
+                                ((u8 *)gpio + sizeof(ATOM_GPIO_I2C_ASSIGMENT));
                 }
         }
 
@@ -195,9 +197,8 @@ void radeon_atombios_i2c_init(struct radeon_device *rdev)
                 num_indices = (size - sizeof(ATOM_COMMON_TABLE_HEADER)) /
                         sizeof(ATOM_GPIO_I2C_ASSIGMENT);
 
+                gpio = &i2c_info->asGPIO_Info[0];
                 for (i = 0; i < num_indices; i++) {
-                        gpio = &i2c_info->asGPIO_Info[i];
-
                         radeon_lookup_i2c_gpio_quirks(rdev, gpio, i);
 
                         i2c = radeon_get_bus_rec_for_i2c_gpio(gpio);
@@ -206,6 +207,8 @@ void radeon_atombios_i2c_init(struct radeon_device *rdev)
                                 sprintf(stmp, "0x%x", i2c.i2c_id);
                                 rdev->i2c_bus[i] = radeon_i2c_create(rdev->ddev, &i2c, stmp);
                         }
+                        gpio = (ATOM_GPIO_I2C_ASSIGMENT *)
+                                ((u8 *)gpio + sizeof(ATOM_GPIO_I2C_ASSIGMENT));
                 }
         }
 }
@@ -230,8 +233,8 @@ static struct radeon_gpio_rec radeon_lookup_gpio(struct radeon_device *rdev,
                 num_indices = (size - sizeof(ATOM_COMMON_TABLE_HEADER)) /
                         sizeof(ATOM_GPIO_PIN_ASSIGNMENT);
 
+                pin = gpio_info->asGPIO_Pin;
                 for (i = 0; i < num_indices; i++) {
-                        pin = &gpio_info->asGPIO_Pin[i];
                         if (id == pin->ucGPIO_ID) {
                                 gpio.id = pin->ucGPIO_ID;
                                 gpio.reg = le16_to_cpu(pin->usGpioPin_AIndex) * 4;
@@ -239,6 +242,8 @@ static struct radeon_gpio_rec radeon_lookup_gpio(struct radeon_device *rdev,
                                 gpio.valid = true;
                                 break;
                         }
+                        pin = (ATOM_GPIO_PIN_ASSIGNMENT *)
+                                ((u8 *)pin + sizeof(ATOM_GPIO_PIN_ASSIGNMENT));
                 }
         }
 
@@ -3413,10 +3418,11 @@ int radeon_atom_get_max_voltage(struct radeon_device *rdev,
                                 ATOM_VOLTAGE_FORMULA_V2 *formula =
                                         &voltage_object->v2.asFormula;
                                 if (formula->ucNumOfVoltageEntries) {
+                                        VOLTAGE_LUT_ENTRY *lut = (VOLTAGE_LUT_ENTRY *)
+                                                ((u8 *)&formula->asVIDAdjustEntries[0] +
+                                                 (sizeof(VOLTAGE_LUT_ENTRY) * (formula->ucNumOfVoltageEntries - 1)));
                                         *max_voltage =
-                                                le16_to_cpu(formula->asVIDAdjustEntries[
-                                                                    formula->ucNumOfVoltageEntries - 1
-                                                                    ].usVoltageValue);
+                                                le16_to_cpu(lut->usVoltageValue);
                                         return 0;
                                 }
                         }
@@ -3576,11 +3582,13 @@ int radeon_atom_get_voltage_table(struct radeon_device *rdev,
                                 if (voltage_object) {
                                         ATOM_VOLTAGE_FORMULA_V2 *formula =
                                                 &voltage_object->v2.asFormula;
+                                        VOLTAGE_LUT_ENTRY *lut;
                                         if (formula->ucNumOfVoltageEntries > MAX_VOLTAGE_ENTRIES)
                                                 return -EINVAL;
+                                        lut = &formula->asVIDAdjustEntries[0];
                                         for (i = 0; i < formula->ucNumOfVoltageEntries; i++) {
                                                 voltage_table->entries[i].value =
-                                                        le16_to_cpu(formula->asVIDAdjustEntries[i].usVoltageValue);
+                                                        le16_to_cpu(lut->usVoltageValue);
                                                 ret = radeon_atom_get_voltage_gpio_settings(rdev,
                                                                                             voltage_table->entries[i].value,
                                                                                             voltage_type,
@@ -3588,6 +3596,8 @@ int radeon_atom_get_voltage_table(struct radeon_device *rdev,
                                                                                             &voltage_table->mask_low);
                                                 if (ret)
                                                         return ret;
+                                                lut = (VOLTAGE_LUT_ENTRY *)
+                                                        ((u8 *)lut + sizeof(VOLTAGE_LUT_ENTRY));
                                         }
                                         voltage_table->count = formula->ucNumOfVoltageEntries;
                                         return 0;
@@ -3607,13 +3617,17 @@ int radeon_atom_get_voltage_table(struct radeon_device *rdev,
                                 if (voltage_object) {
                                         ATOM_GPIO_VOLTAGE_OBJECT_V3 *gpio =
                                                 &voltage_object->v3.asGpioVoltageObj;
+                                        VOLTAGE_LUT_ENTRY_V2 *lut;
                                         if (gpio->ucGpioEntryNum > MAX_VOLTAGE_ENTRIES)
                                                 return -EINVAL;
+                                        lut = &gpio->asVolGpioLut[0];
                                         for (i = 0; i < gpio->ucGpioEntryNum; i++) {
                                                 voltage_table->entries[i].value =
-                                                        le16_to_cpu(gpio->asVolGpioLut[i].usVoltageValue);
+                                                        le16_to_cpu(lut->usVoltageValue);
                                                 voltage_table->entries[i].smio_low =
-                                                        le32_to_cpu(gpio->asVolGpioLut[i].ulVoltageId);
+                                                        le32_to_cpu(lut->ulVoltageId);
+                                                lut = (VOLTAGE_LUT_ENTRY_V2 *)
+                                                        ((u8 *)lut + sizeof(VOLTAGE_LUT_ENTRY_V2));
                                         }
                                         voltage_table->mask_low = le32_to_cpu(gpio->ulGpioMaskVal);
                                         voltage_table->count = gpio->ucGpioEntryNum;
@@ -3739,7 +3753,6 @@ int radeon_atom_get_mclk_range_table(struct radeon_device *rdev,
         union vram_info *vram_info;
         u32 mem_timing_size = gddr5 ?
                 sizeof(ATOM_MEMORY_TIMING_FORMAT_V2) : sizeof(ATOM_MEMORY_TIMING_FORMAT);
-        u8 *p;
 
         memset(mclk_range_table, 0, sizeof(struct atom_memory_clock_range_table));
 
@@ -3758,6 +3771,7 @@ int radeon_atom_get_mclk_range_table(struct radeon_device *rdev,
                                 if (module_index < vram_info->v1_4.ucNumOfVRAMModule) {
                                         ATOM_VRAM_MODULE_V4 *vram_module =
                                                 (ATOM_VRAM_MODULE_V4 *)vram_info->v1_4.aVramInfo;
+                                        ATOM_MEMORY_TIMING_FORMAT *format;
 
                                         for (i = 0; i < module_index; i++) {
                                                 if (le16_to_cpu(vram_module->usModuleSize) == 0)
@@ -3768,11 +3782,11 @@ int radeon_atom_get_mclk_range_table(struct radeon_device *rdev,
                                         mclk_range_table->num_entries = (u8)
                                                 ((le16_to_cpu(vram_module->usModuleSize) - offsetof(ATOM_VRAM_MODULE_V4, asMemTiming)) /
                                                  mem_timing_size);
-                                        p = (u8 *)&vram_module->asMemTiming[0];
+                                        format = &vram_module->asMemTiming[0];
                                         for (i = 0; i < mclk_range_table->num_entries; i++) {
-                                                ATOM_MEMORY_TIMING_FORMAT *format = (ATOM_MEMORY_TIMING_FORMAT *)p;
                                                 mclk_range_table->mclk[i] = le32_to_cpu(format->ulClkRange);
-                                                p += mem_timing_size;
+                                                format = (ATOM_MEMORY_TIMING_FORMAT *)
+                                                        ((u8 *)format + mem_timing_size);
                                         }
                                 } else
                                         return -EINVAL;