drm/nv50: improve nv50_pm_get_clock()

Many of the nv50 cards have their shader and/or memory pll
disabled at some stage.
This patch addresses those cases, so that the function
returns the correct frequency.

When the shader pll is disabled, the blob reports 2*core clock
Whereas for memory, the data stored in the vbios. This action
is incorrect as some vbioses store a clock value that is less
than the refference clock of the pll.

Thus we are reporting the reff_clk as it is the frequency the
pll actually operates

v2 - Convert NV_INFO() messages to NV_DEBUG()
Provide more information in the actuall message

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nv50_pm.c b/drivers/gpu/drm/nouveau/nv50_pm.c
index 7dbb305d7e63598056678c8e3e20b594c8c25a18..8a2810011bda5e9cd1861d03ecf3482229be20da 100644 (file)
--- a/drivers/gpu/drm/nouveau/nv50_pm.c
+++ b/drivers/gpu/drm/nouveau/nv50_pm.c
@@ -47,6 +47,21 @@ nv50_pm_clock_get(struct drm_device *dev, u32 id)
 
        reg0 = nv_rd32(dev, pll.reg + 0);
        reg1 = nv_rd32(dev, pll.reg + 4);
+
+       if ((reg0 & 0x80000000) == 0) {
+               if (id == PLL_SHADER) {
+                       NV_DEBUG(dev, "Shader PLL is disabled. "
+                               "Shader clock is twice the core\n");
+                       ret = nv50_pm_clock_get(dev, PLL_CORE);
+                       if (ret > 0)
+                               return ret << 1;
+               } else if (id == PLL_MEMORY) {
+                       NV_DEBUG(dev, "Memory PLL is disabled. "
+                               "Memory clock is equal to the ref_clk\n");
+                       return pll.refclk;
+               }
+       }
+
        P = (reg0 & 0x00070000) >> 16;
        N = (reg1 & 0x0000ff00) >> 8;
        M = (reg1 & 0x000000ff);