drm/nva3/pm: tidy and add some comments here and there

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nva3_pm.c b/drivers/gpu/drm/nouveau/nva3_pm.c
index a9e3de4a9520d87a85c2e8323769be0805b15da6..98ea3aa0bb650ca0c4dcc923aa4c69264e891129 100644 (file)
--- a/drivers/gpu/drm/nouveau/nva3_pm.c
+++ b/drivers/gpu/drm/nouveau/nva3_pm.c
@@ -28,15 +28,15 @@
 #include "nouveau_pm.h"
 
 static u32 read_clk(struct drm_device *, int, bool);
-static u32 read_pll(struct drm_device *, u32, int);
+static u32 read_pll(struct drm_device *, int, u32);
 
 static u32
 read_vco(struct drm_device *dev, int clk)
 {
        u32 sctl = nv_rd32(dev, 0x4120 + (clk * 4));
        if ((sctl & 0x00000030) != 0x00000030)
-               return read_pll(dev, 0x00e820, 0x41);
-       return read_pll(dev, 0x00e8a0, 0x42);
+               return read_pll(dev, 0x41, 0x00e820);
+       return read_pll(dev, 0x42, 0x00e8a0);
 }
 
 static u32
@@ -44,6 +44,7 @@ read_clk(struct drm_device *dev, int clk, bool ignore_en)
 {
        u32 sctl, sdiv, sclk;
 
+       /* refclk for the 0xe8xx plls always 27KHz */
        if (clk >= 0x40)
                return 27000;
 
@@ -68,7 +69,7 @@ read_clk(struct drm_device *dev, int clk, bool ignore_en)
 }
 
 static u32
-read_pll(struct drm_device *dev, u32 pll, int clk)
+read_pll(struct drm_device *dev, int clk, u32 pll)
 {
        u32 ctrl = nv_rd32(dev, pll + 0);
        u32 sclk, P = 1, N = 1, M = 1;
@@ -78,6 +79,8 @@ read_pll(struct drm_device *dev, u32 pll, int clk)
                M = (coef & 0x000000ff) >> 0;
                N = (coef & 0x0000ff00) >> 8;
                P = (coef & 0x003f0000) >> 16;
+
+               /* not post-divider on these.. */
                if ((pll & 0x00ff00) == 0x00e800)
                        P = 1;
 
@@ -95,7 +98,7 @@ struct creg {
 };
 
 static int
-calc_clk(struct drm_device *dev, u32 pll, int clk, u32 khz, struct creg *reg)
+calc_clk(struct drm_device *dev, int clk, u32 pll, u32 khz, struct creg *reg)
 {
        struct pll_lims limits;
        u32 oclk, sclk, sdiv;
@@ -104,6 +107,10 @@ calc_clk(struct drm_device *dev, u32 pll, int clk, u32 khz, struct creg *reg)
 
        reg->pll = 0;
        reg->clk = 0;
+       if (!khz) {
+               NV_DEBUG(dev, "no clock for 0x%04x/0x%02x\n", pll, clk);
+               return 0;
+       }
 
        switch (khz) {
        case 27000:
@@ -118,6 +125,14 @@ calc_clk(struct drm_device *dev, u32 pll, int clk, u32 khz, struct creg *reg)
        default:
                sclk = read_vco(dev, clk);
                sdiv = min((sclk * 2) / (khz - 2999), (u32)65);
+               /* if the clock has a PLL attached, and we can get a within
+                * [-2, 3) MHz of a divider, we'll disable the PLL and use
+                * the divider instead.
+                *
+                * divider can go as low as 2, limited here because NVIDIA
+                * and the VBIOS on my NVA8 seem to prefer using the PLL
+                * for 810MHz - is there a good reason?
+                */
                if (sdiv > 4) {
                        oclk = (sclk * 2) / sdiv;
                        diff = khz - oclk;
@@ -126,6 +141,12 @@ calc_clk(struct drm_device *dev, u32 pll, int clk, u32 khz, struct creg *reg)
                                return oclk;
                        }
                }
+
+               if (!pll) {
+                       NV_ERROR(dev, "bad freq %02x: %d %d\n", clk, khz, sclk);
+                       return -ERANGE;
+               }
+
                break;
        }
 
@@ -145,12 +166,53 @@ calc_clk(struct drm_device *dev, u32 pll, int clk, u32 khz, struct creg *reg)
        return ret;
 }
 
+static void
+prog_pll(struct drm_device *dev, int clk, u32 pll, struct creg *reg)
+{
+       const u32 src0 = 0x004120 + (clk * 4);
+       const u32 src1 = 0x004160 + (clk * 4);
+       const u32 ctrl = pll + 0;
+       const u32 coef = pll + 4;
+       u32 cntl;
+
+       if (!reg->clk && !reg->pll) {
+               NV_DEBUG(dev, "no clock for %02x\n", clk);
+               return;
+       }
+
+       cntl = nv_rd32(dev, ctrl) & 0xfffffff2;
+       if (reg->pll) {
+               nv_mask(dev, src0, 0x00000101, 0x00000101);
+               nv_wr32(dev, coef, reg->pll);
+               nv_wr32(dev, ctrl, cntl | 0x00000015);
+               nv_mask(dev, src1, 0x00000100, 0x00000000);
+               nv_mask(dev, src1, 0x00000001, 0x00000000);
+       } else {
+               nv_mask(dev, src1, 0x003f3141, 0x00000101 | reg->clk);
+               nv_wr32(dev, ctrl, cntl | 0x0000001d);
+               nv_mask(dev, ctrl, 0x00000001, 0x00000000);
+               nv_mask(dev, src0, 0x00000100, 0x00000000);
+               nv_mask(dev, src0, 0x00000001, 0x00000000);
+       }
+}
+
+static void
+prog_clk(struct drm_device *dev, int clk, struct creg *reg)
+{
+       if (!reg->clk) {
+               NV_DEBUG(dev, "no clock for %02x\n", clk);
+               return;
+       }
+
+       nv_mask(dev, 0x004120 + (clk * 4), 0x003f3141, 0x00000101 | reg->clk);
+}
+
 int
 nva3_pm_clocks_get(struct drm_device *dev, struct nouveau_pm_level *perflvl)
 {
-       perflvl->core   = read_pll(dev, 0x4200, 0);
-       perflvl->shader = read_pll(dev, 0x4220, 1);
-       perflvl->memory = read_pll(dev, 0x4000, 2);
+       perflvl->core   = read_pll(dev, 0x00, 0x4200);
+       perflvl->shader = read_pll(dev, 0x01, 0x4220);
+       perflvl->memory = read_pll(dev, 0x02, 0x4000);
        perflvl->unka0  = read_clk(dev, 0x20, false);
        perflvl->vdec   = read_clk(dev, 0x21, false);
        return 0;
@@ -174,23 +236,23 @@ nva3_pm_clocks_pre(struct drm_device *dev, struct nouveau_pm_level *perflvl)
        if (!info)
                return ERR_PTR(-ENOMEM);
 
-       ret = calc_clk(dev, 0x4200, 0x10, perflvl->core, &info->nclk);
+       ret = calc_clk(dev, 0x10, 0x4200, perflvl->core, &info->nclk);
        if (ret < 0)
                goto out;
 
-       ret = calc_clk(dev, 0x4220, 0x11, perflvl->shader, &info->sclk);
+       ret = calc_clk(dev, 0x11, 0x4220, perflvl->shader, &info->sclk);
        if (ret < 0)
                goto out;
 
-       ret = calc_clk(dev, 0x4000, 0x12, perflvl->memory, &info->mclk);
+       ret = calc_clk(dev, 0x12, 0x4000, perflvl->memory, &info->mclk);
        if (ret < 0)
                goto out;
 
-       ret = calc_clk(dev, 0x0000, 0x20, perflvl->unka0, &info->unka0);
+       ret = calc_clk(dev, 0x20, 0x0000, perflvl->unka0, &info->unka0);
        if (ret < 0)
                goto out;
 
-       ret = calc_clk(dev, 0x0000, 0x21, perflvl->vdec, &info->vdec);
+       ret = calc_clk(dev, 0x21, 0x0000, perflvl->vdec, &info->vdec);
        if (ret < 0)
                goto out;
 
@@ -202,51 +264,20 @@ out:
        return info;
 }
 
-static void
-prog_pll(struct drm_device *dev, u32 pll, int clk, struct creg *reg)
-{
-       const u32 src0 = 0x004120 + (clk * 4);
-       const u32 src1 = 0x004160 + (clk * 4);
-       const u32 ctrl = pll + 0;
-       const u32 coef = pll + 4;
-       u32 cntl;
-
-       cntl = nv_rd32(dev, ctrl) & 0xfffffff2;
-       if (reg->pll) {
-               nv_mask(dev, src0, 0x00000101, 0x00000101);
-               nv_wr32(dev, coef, reg->pll);
-               nv_wr32(dev, ctrl, cntl | 0x00000015);
-               nv_mask(dev, src1, 0x00000100, 0x00000000);
-               nv_mask(dev, src1, 0x00000001, 0x00000000);
-       } else {
-               nv_mask(dev, src1, 0x003f3141, 0x00000101 | reg->clk);
-               nv_wr32(dev, ctrl, cntl | 0x0000001d);
-               nv_mask(dev, ctrl, 0x00000001, 0x00000000);
-               nv_mask(dev, src0, 0x00000100, 0x00000000);
-               nv_mask(dev, src0, 0x00000001, 0x00000000);
-       }
-}
-
-static void
-prog_clk(struct drm_device *dev, int clk, struct creg *reg)
-{
-       nv_mask(dev, 0x004120 + (clk * 4), 0x003f3141, 0x00000101 | reg->clk);
-}
-
 void
 nva3_pm_clocks_set(struct drm_device *dev, void *pre_state)
 {
        struct nva3_pm_state *info = pre_state;
 
-       prog_pll(dev, 0x004200, 0, &info->nclk);
-       prog_pll(dev, 0x004220, 1, &info->sclk);
+       prog_pll(dev, 0x00, 0x004200, &info->nclk);
+       prog_pll(dev, 0x01, 0x004220, &info->sclk);
        prog_clk(dev, 0x20, &info->unka0);
        prog_clk(dev, 0x21, &info->vdec);
 
        nv_wr32(dev, 0x100210, 0);
        nv_wr32(dev, 0x1002dc, 1);
        nv_wr32(dev, 0x004018, 0x00001000);
-       prog_pll(dev, 0x004000, 2, &info->mclk);
+       prog_pll(dev, 0x02, 0x004000, &info->mclk);
        if (nv_rd32(dev, 0x4000) & 0x00000008)
                nv_wr32(dev, 0x004018, 0x1000d000);
        else