drm/nouveau/i2c: properly hand aux reply back to caller, and only retry on defer

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

4 files changed, 20 insertions, 14 deletions

diff --git a/drivers/gpu/drm/nouveau/core/include/subdev/i2c.h b/drivers/gpu/drm/nouveau/core/include/subdev/i2c.h
index 7f50a858b16f..05f4453fd752 100644
--- a/drivers/gpu/drm/nouveau/core/include/subdev/i2c.h
+++ b/drivers/gpu/drm/nouveau/core/include/subdev/i2c.h
@@ -33,7 +33,7 @@ struct nouveau_i2c_func {
         int  (*sense_scl)(struct nouveau_i2c_port *);
         int  (*sense_sda)(struct nouveau_i2c_port *);
 
-        int  (*aux)(struct nouveau_i2c_port *, u8, u32, u8 *, u8);
+        int  (*aux)(struct nouveau_i2c_port *, bool, u8, u32, u8 *, u8);
         int  (*pattern)(struct nouveau_i2c_port *, int pattern);
         int  (*lnk_ctl)(struct nouveau_i2c_port *, int nr, int bw, bool enh);
         int  (*drv_ctl)(struct nouveau_i2c_port *, int lane, int sw, int pe);
diff --git a/drivers/gpu/drm/nouveau/core/subdev/i2c/anx9805.c b/drivers/gpu/drm/nouveau/core/subdev/i2c/anx9805.c
index 4b195ac4da66..29a5a7fe5c2b 100644
--- a/drivers/gpu/drm/nouveau/core/subdev/i2c/anx9805.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/i2c/anx9805.c
@@ -60,7 +60,8 @@ anx9805_train(struct nouveau_i2c_port *port, int link_nr, int link_bw, bool enh)
 }
 
 static int
-anx9805_aux(struct nouveau_i2c_port *port, u8 type, u32 addr, u8 *data, u8 size)
+anx9805_aux(struct nouveau_i2c_port *port, bool retry,
+            u8 type, u32 addr, u8 *data, u8 size)
 {
         struct anx9805_i2c_port *chan = (void *)port;
         struct nouveau_i2c_port *mast = (void *)nv_object(chan)->parent;
diff --git a/drivers/gpu/drm/nouveau/core/subdev/i2c/aux.c b/drivers/gpu/drm/nouveau/core/subdev/i2c/aux.c
index 5de074ad170b..73d027b281f2 100644
--- a/drivers/gpu/drm/nouveau/core/subdev/i2c/aux.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/i2c/aux.c
@@ -30,7 +30,7 @@ nv_rdaux(struct nouveau_i2c_port *port, u32 addr, u8 *data, u8 size)
         if (port->func->aux) {
                 if (port->func->acquire)
                         port->func->acquire(port);
-                return port->func->aux(port, 9, addr, data, size);
+                return port->func->aux(port, true, 9, addr, data, size);
         }
         return -ENODEV;
 }
@@ -41,7 +41,7 @@ nv_wraux(struct nouveau_i2c_port *port, u32 addr, u8 *data, u8 size)
         if (port->func->aux) {
                 if (port->func->acquire)
                         port->func->acquire(port);
-                return port->func->aux(port, 8, addr, data, size);
+                return port->func->aux(port, true, 8, addr, data, size);
         }
         return -ENODEV;
 }
@@ -74,7 +74,7 @@ aux_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
                         if (mcnt || remaining > 16)
                                 cmd |= 4; /* MOT */
 
-                        ret = port->func->aux(port, cmd, msg->addr, ptr, cnt);
+                        ret = port->func->aux(port, true, cmd, msg->addr, ptr, cnt);
                         if (ret < 0)
                                 return ret;
 
diff --git a/drivers/gpu/drm/nouveau/core/subdev/i2c/nv94.c b/drivers/gpu/drm/nouveau/core/subdev/i2c/nv94.c
index df6d3e4b68be..d790ef165f92 100644
--- a/drivers/gpu/drm/nouveau/core/subdev/i2c/nv94.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/i2c/nv94.c
@@ -69,7 +69,8 @@ auxch_init(struct nouveau_i2c *aux, int ch)
 }
 
 int
-nv94_aux(struct nouveau_i2c_port *base, u8 type, u32 addr, u8 *data, u8 size)
+nv94_aux(struct nouveau_i2c_port *base, bool retry,
+         u8 type, u32 addr, u8 *data, u8 size)
 {
         struct nouveau_i2c *aux = nouveau_i2c(base);
         struct nv50_i2c_port *port = (void *)base;
@@ -105,9 +106,8 @@ nv94_aux(struct nouveau_i2c_port *base, u8 type, u32 addr, u8 *data, u8 size)
         ctrl |= size - 1;
         nv_wr32(aux, 0x00e4e0 + (ch * 0x50), addr);
 
-        /* retry transaction a number of times on failure... */
-        ret = -EREMOTEIO;
-        for (retries = 0; retries < 32; retries++) {
+        /* (maybe) retry transaction a number of times on failure... */
+        for (retries = 0; !ret && retries < 32; retries++) {
                 /* reset, and delay a while if this is a retry */
                 nv_wr32(aux, 0x00e4e4 + (ch * 0x50), 0x80000000 | ctrl);
                 nv_wr32(aux, 0x00e4e4 + (ch * 0x50), 0x00000000 | ctrl);
@@ -123,16 +123,21 @@ nv94_aux(struct nouveau_i2c_port *base, u8 type, u32 addr, u8 *data, u8 size)
                         udelay(1);
                         if (!timeout--) {
                                 AUX_ERR("tx req timeout 0x%08x\n", ctrl);
+                                ret = -EIO;
                                 goto out;
                         }
                 } while (ctrl & 0x00010000);
+                ret = 1;
 
                 /* read status, and check if transaction completed ok */
                 stat = nv_mask(aux, 0x00e4e8 + (ch * 0x50), 0, 0);
-                if (!(stat & 0x000f0f00)) {
-                        ret = 0;
-                        break;
-                }
+                if ((stat & 0x000f0000) == 0x00080000 ||
+                    (stat & 0x000f0000) == 0x00020000)
+                        ret = retry ? 0 : 1;
+                if ((stat & 0x00000100))
+                        ret = -ETIMEDOUT;
+                if ((stat & 0x00000e00))
+                        ret = -EIO;
 
                 AUX_DBG("%02d 0x%08x 0x%08x\n", retries, ctrl, stat);
         }
@@ -147,7 +152,7 @@ nv94_aux(struct nouveau_i2c_port *base, u8 type, u32 addr, u8 *data, u8 size)
 
 out:
         auxch_fini(aux, ch);
-        return ret;
+        return ret < 0 ? ret : (stat & 0x000f0000) >> 16;
 }
 
 void