drm/radeon: fix and simplify pot argument checks v3

GART and VRAM size limits need to be a power of two.
Fix values greater than 1GB and simplify those checks a bit.

v2: also fix radeon_vram_limit usage, and simplify test even more.
v3: agd5f: fix spelling as noticed by Klaus Schnass

Signed-off-by: Christian König <deathsimple@vodafone.de>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 24 insertions, 36 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index bd13ca09eb62..e2f5f888c374 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -355,6 +355,8 @@ int radeon_wb_init(struct radeon_device *rdev)
  */
 void radeon_vram_location(struct radeon_device *rdev, struct radeon_mc *mc, u64 base)
 {
+        uint64_t limit = (uint64_t)radeon_vram_limit << 20;
+
         mc->vram_start = base;
         if (mc->mc_vram_size > (0xFFFFFFFF - base + 1)) {
                 dev_warn(rdev->dev, "limiting VRAM to PCI aperture size\n");
@@ -368,8 +370,8 @@ void radeon_vram_location(struct radeon_device *rdev, struct radeon_mc *mc, u64
                 mc->mc_vram_size = mc->aper_size;
         }
         mc->vram_end = mc->vram_start + mc->mc_vram_size - 1;
-        if (radeon_vram_limit && radeon_vram_limit < mc->real_vram_size)
-                mc->real_vram_size = radeon_vram_limit;
+        if (limit && limit < mc->real_vram_size)
+                mc->real_vram_size = limit;
         dev_info(rdev->dev, "VRAM: %lluM 0x%016llX - 0x%016llX (%lluM used)\n",
                         mc->mc_vram_size >> 20, mc->vram_start,
                         mc->vram_end, mc->real_vram_size >> 20);
@@ -835,6 +837,19 @@ static unsigned int radeon_vga_set_decode(void *cookie, bool state)
 }
 
 /**
+ * radeon_check_pot_argument - check that argument is a power of two
+ *
+ * @arg: value to check
+ *
+ * Validates that a certain argument is a power of two (all asics).
+ * Returns true if argument is valid.
+ */
+static bool radeon_check_pot_argument(int arg)
+{
+        return (arg & (arg - 1)) == 0;
+}
+
+/**
  * radeon_check_arguments - validate module params
  *
  * @rdev: radeon_device pointer
@@ -845,52 +860,25 @@ static unsigned int radeon_vga_set_decode(void *cookie, bool state)
 static void radeon_check_arguments(struct radeon_device *rdev)
 {
         /* vramlimit must be a power of two */
-        switch (radeon_vram_limit) {
-        case 0:
-        case 4:
-        case 8:
-        case 16:
-        case 32:
-        case 64:
-        case 128:
-        case 256:
-        case 512:
-        case 1024:
-        case 2048:
-        case 4096:
-                break;
-        default:
+        if (!radeon_check_pot_argument(radeon_vram_limit)) {
                 dev_warn(rdev->dev, "vram limit (%d) must be a power of 2\n",
                                 radeon_vram_limit);
                 radeon_vram_limit = 0;
-                break;
         }
-        radeon_vram_limit = radeon_vram_limit << 20;
+
         /* gtt size must be power of two and greater or equal to 32M */
-        switch (radeon_gart_size) {
-        case 4:
-        case 8:
-        case 16:
+        if (radeon_gart_size < 32) {
                 dev_warn(rdev->dev, "gart size (%d) too small forcing to 512M\n",
                                 radeon_gart_size);
                 radeon_gart_size = 512;
-                break;
-        case 32:
-        case 64:
-        case 128:
-        case 256:
-        case 512:
-        case 1024:
-        case 2048:
-        case 4096:
-                break;
-        default:
+
+        } else if (!radeon_check_pot_argument(radeon_gart_size)) {
                 dev_warn(rdev->dev, "gart size (%d) must be a power of 2\n",
                                 radeon_gart_size);
                 radeon_gart_size = 512;
-                break;
         }
-        rdev->mc.gtt_size = radeon_gart_size * 1024 * 1024;
+        rdev->mc.gtt_size = (uint64_t)radeon_gart_size << 20;
+
         /* AGP mode can only be -1, 1, 2, 4, 8 */
         switch (radeon_agpmode) {
         case -1: