drm/nouveau/mxm: implement ROM shadow method

Untested, -ENOHW.

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

1 files changed, 39 insertions, 0 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_mxm.c b/drivers/gpu/drm/nouveau/nouveau_mxm.c
index 840c88fc4f0e..8bccddf4eff0 100644
--- a/drivers/gpu/drm/nouveau/nouveau_mxm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_mxm.c
@@ -471,8 +471,47 @@ mxm_dcb_sanitise(struct drm_device *dev)
 }
 
 static bool
+mxm_shadow_rom_fetch(struct nouveau_i2c_chan *i2c, u8 addr,
+                     u8 offset, u8 size, u8 *data)
+{
+        struct i2c_msg msgs[] = {
+                { .addr = addr, .flags = 0, .len = 1, .buf = &offset },
+                { .addr = addr, .flags = I2C_M_RD, .len = size, .buf = data, },
+        };
+
+        return i2c_transfer(&i2c->adapter, msgs, 2) == 2;
+}
+
+static bool
 mxm_shadow_rom(struct drm_device *dev, u8 version)
 {
+        struct drm_nouveau_private *dev_priv = dev->dev_private;
+        struct nouveau_i2c_chan *i2c = NULL;
+        u8 i2cidx, mxms[6], addr, size;
+
+        i2cidx = mxm_ddc_map(dev, 1 /* LVDS_DDC */) & 0x0f;
+        if (i2cidx < 0x0f)
+                i2c = nouveau_i2c_find(dev, i2cidx);
+        if (!i2c)
+                return false;
+
+        addr = 0x54;
+        if (!mxm_shadow_rom_fetch(i2c, addr, 0, 6, mxms)) {
+                addr = 0x56;
+                if (!mxm_shadow_rom_fetch(i2c, addr, 0, 6, mxms))
+                        return false;
+        }
+
+        dev_priv->mxms = mxms;
+        size = mxms_headerlen(dev) + mxms_structlen(dev);
+        dev_priv->mxms = kmalloc(size, GFP_KERNEL);
+
+        if (dev_priv->mxms &&
+            mxm_shadow_rom_fetch(i2c, addr, 0, size, dev_priv->mxms))
+                return true;
+
+        kfree(dev_priv->mxms);
+        dev_priv->mxms = NULL;
         return false;
 }