i2c: balance port acquire/release

This was a half-finished hack before, just enough to handle the shared
aux/i2c pad thing on G94 and up.

We got lucky with locking etc up until now, as this was (generally) all
protected by the DRM mode_config lock.  It's about to become a lot more
likely to hit the races.

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

5 files changed, 63 insertions, 18 deletions

diff --git a/lib/core/os.h b/lib/core/os.h
index 867d8128..456daa77 100644
--- a/lib/core/os.h
+++ b/lib/core/os.h
@@ -78,8 +78,9 @@ typedef dma_addr_t resource_size_t;
 #define unlikely(a) (a)
 #define BIT(a) (1UL << (a))
 
-#define jiffies (ktime_to_us(ktime_get()))
-#define usecs_to_jiffies(a) (a)
+#define jiffies (ktime_to_ns(ktime_get()))
+#define nsecs_to_jiffies(a) (a)
+#define usecs_to_jiffies(a) nsecs_to_jiffies((a) * 1000)
 #define msecs_to_jiffies(a) usecs_to_jiffies((a) * 1000)
 #define HZ 1000000
 
@@ -906,6 +907,7 @@ typedef struct __wait_queue_head {
 
 #define init_waitqueue_head(wq)
 #define wake_up(wq)
+#define wake_up_all(wq)
 
 #define wait_event(wq,cond) do {                                               \
 	usleep(1);                                                             \
@@ -916,7 +918,7 @@ typedef struct __wait_queue_head {
 })
 
 #define wait_event_timeout(wq,cond,jiffies) ({                                 \
-	unsigned long _t = (jiffies) / 10;                                     \
+	unsigned long _t = (jiffies) / 10000;                                  \
 	do {                                                                   \
 		if (cond)                                                      \
 			break;                                                 \
@@ -1034,13 +1036,14 @@ i2c_bit_algo = {
 
 struct i2c_algo_bit_data {
 	int udelay;
-	int timeout;
+	unsigned long timeout;
 	void *data;
 	void (*setsda) (void *data, int state);
 	void (*setscl) (void *data, int state);
 	int  (*getsda) (void *data);
 	int  (*getscl) (void *data);
 	int  (*pre_xfer)(struct i2c_adapter *);
+	void (*post_xfer)(struct i2c_adapter *);
 };
 
 static inline int
diff --git a/nvkm/include/subdev/i2c.h b/nvkm/include/subdev/i2c.h
index aaa36158..9c150568 100644
--- a/nvkm/include/subdev/i2c.h
+++ b/nvkm/include/subdev/i2c.h
@@ -62,6 +62,8 @@ struct nouveau_i2c {
 
 	struct nouveau_i2c_port *(*find)(struct nouveau_i2c *, u8 index);
 	struct nouveau_i2c_port *(*find_type)(struct nouveau_i2c *, u16 type);
+	int  (*acquire)(struct nouveau_i2c_port *, unsigned long timeout);
+	void (*release)(struct nouveau_i2c_port *);
 	int (*identify)(struct nouveau_i2c *, int index,
 			const char *what, struct nouveau_i2c_board_info *,
 			bool (*match)(struct nouveau_i2c_port *,
diff --git a/nvkm/subdev/i2c/aux.c b/nvkm/subdev/i2c/aux.c
index cad742bd..02eb42be 100644
--- a/nvkm/subdev/i2c/aux.c
+++ b/nvkm/subdev/i2c/aux.c
@@ -27,10 +27,14 @@
 int
 nv_rdaux(struct nouveau_i2c_port *port, u32 addr, u8 *data, u8 size)
 {
+	struct nouveau_i2c *i2c = nouveau_i2c(port);
 	if (port->func->aux) {
-		if (port->func->acquire)
-			port->func->acquire(port);
-		return port->func->aux(port, true, 9, addr, data, size);
+		int ret = i2c->acquire(port, 0);
+		if (ret == 0) {
+			ret = port->func->aux(port, true, 9, addr, data, size);
+			i2c->release(port);
+		}
+		return ret;
 	}
 	return -ENODEV;
 }
@@ -38,10 +42,14 @@ nv_rdaux(struct nouveau_i2c_port *port, u32 addr, u8 *data, u8 size)
 int
 nv_wraux(struct nouveau_i2c_port *port, u32 addr, u8 *data, u8 size)
 {
+	struct nouveau_i2c *i2c = nouveau_i2c(port);
 	if (port->func->aux) {
-		if (port->func->acquire)
-			port->func->acquire(port);
-		return port->func->aux(port, true, 8, addr, data, size);
+		int ret = i2c->acquire(port, 0);
+		if (ret == 0) {
+			ret = port->func->aux(port, true, 8, addr, data, size);
+			i2c->release(port);
+		}
+		return ret;
 	}
 	return -ENODEV;
 }
@@ -50,13 +58,16 @@ static int
 aux_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 {
 	struct nouveau_i2c_port *port = adap->algo_data;
+	struct nouveau_i2c *i2c = nouveau_i2c(port);
 	struct i2c_msg *msg = msgs;
 	int ret, mcnt = num;
 
 	if (!port->func->aux)
 		return -ENODEV;
-	if ( port->func->acquire)
-		port->func->acquire(port);
+
+	ret = i2c->acquire(port, 0);
+	if (ret)
+		return ret;
 
 	while (mcnt--) {
 		u8 remaining = msg->len;
@@ -75,8 +86,10 @@ aux_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 				cmd |= 4; /* MOT */
 
 			ret = port->func->aux(port, true, cmd, msg->addr, ptr, cnt);
-			if (ret < 0)
+			if (ret < 0) {
+				i2c->release(port);
 				return ret;
+			}
 
 			ptr += cnt;
 			remaining -= cnt;
@@ -85,6 +98,7 @@ aux_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 		msg++;
 	}
 
+	i2c->release(port);
 	return num;
 }
 
diff --git a/nvkm/subdev/i2c/base.c b/nvkm/subdev/i2c/base.c
index 0e360576..a230465f 100644
--- a/nvkm/subdev/i2c/base.c
+++ b/nvkm/subdev/i2c/base.c
@@ -47,9 +47,15 @@ nouveau_i2c_pre_xfer(struct i2c_adapter *adap)
 {
 	struct i2c_algo_bit_data *bit = adap->algo_data;
 	struct nouveau_i2c_port *port = bit->data;
-	if (port->func->acquire)
-		port->func->acquire(port);
-	return 0;
+	return nouveau_i2c(port)->acquire(port, bit->timeout);
+}
+
+static void
+nouveau_i2c_post_xfer(struct i2c_adapter *adap)
+{
+	struct i2c_algo_bit_data *bit = adap->algo_data;
+	struct nouveau_i2c_port *port = bit->data;
+	return nouveau_i2c(port)->release(port);
 }
 
 static void
@@ -130,6 +136,7 @@ nouveau_i2c_port_create_(struct nouveau_object *parent,
 		bit->timeout = usecs_to_jiffies(2200);
 		bit->data = port;
 		bit->pre_xfer = nouveau_i2c_pre_xfer;
+		bit->post_xfer = nouveau_i2c_post_xfer;
 		bit->setsda = nouveau_i2c_setsda;
 		bit->setscl = nouveau_i2c_setscl;
 		bit->getsda = nouveau_i2c_getsda;
@@ -194,6 +201,21 @@ nouveau_i2c_find_type(struct nouveau_i2c *i2c, u16 type)
 	return NULL;
 }
 
+static void
+nouveau_i2c_release(struct nouveau_i2c_port *port)
+{
+	if (port->func->release)
+		port->func->release(port);
+}
+
+static int
+nouveau_i2c_acquire(struct nouveau_i2c_port *port, unsigned long timeout)
+{
+	if (port->func->acquire)
+		port->func->acquire(port);
+	return 0;
+}
+
 static int
 nouveau_i2c_identify(struct nouveau_i2c *i2c, int index, const char *what,
 		     struct nouveau_i2c_board_info *info,
@@ -383,6 +405,8 @@ nouveau_i2c_create_(struct nouveau_object *parent,
 	nv_subdev(i2c)->intr = nouveau_i2c_intr;
 	i2c->find = nouveau_i2c_find;
 	i2c->find_type = nouveau_i2c_find_type;
+	i2c->acquire = nouveau_i2c_acquire;
+	i2c->release = nouveau_i2c_release;
 	i2c->identify = nouveau_i2c_identify;
 	INIT_LIST_HEAD(&i2c->ports);
 
diff --git a/nvkm/subdev/i2c/bit.c b/nvkm/subdev/i2c/bit.c
index 8fda0547..813ffc96 100644
--- a/nvkm/subdev/i2c/bit.c
+++ b/nvkm/subdev/i2c/bit.c
@@ -187,8 +187,9 @@ i2c_bit_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 	struct i2c_msg *msg = msgs;
 	int ret = 0, mcnt = num;
 
-	if (port->func->acquire)
-		port->func->acquire(port);
+	ret = nouveau_i2c(port)->acquire(port, nsecs_to_jiffies(T_TIMEOUT));
+	if (ret)
+		return ret;
 
 	while (!ret && mcnt--) {
 		u8 remaining = msg->len;
@@ -210,6 +211,7 @@ i2c_bit_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 	}
 
 	i2c_stop(port);
+	nouveau_i2c(port)->release(port);
 	return (ret < 0) ? ret : num;
 }
 #else