rpmsg: glink: Associate indirections for pipe fifo accessor's

With the intention of reusing the glink core protocol commands and code
across both rpm and smem based transports, the only thing different is
way of accessing the shared-memory of the transport (FIFO). So put the
fifo accessor's of the transport's pipe (rx/tx) behind indirections, so
that the rest of the code can be shared.

For this, have a qcom_glink_pipe that can be used in the common code
containing the indirections and wrap it with glink_rpm_pipe that
contains the transport specific members.
Acked-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/rpmsg/qcom_glink_rpm.c

@@ -41,12 +41,28 @@
 #define RPM_GLINK_CID_MIN	1
 #define RPM_GLINK_CID_MAX	65536
 
+#define to_rpm_pipe(p)	container_of(p, struct glink_rpm_pipe, native)
+
 struct rpm_toc_entry {
 	__le32 id;
 	__le32 offset;
 	__le32 size;
 } __packed;
 
+struct qcom_glink;
+
+struct qcom_glink_pipe {
+	size_t length;
+
+	size_t (*avail)(struct qcom_glink_pipe *glink_pipe);
+	void (*peak)(struct qcom_glink_pipe *glink_pipe, void *data,
+		     size_t count);
+	void (*advance)(struct qcom_glink_pipe *glink_pipe, size_t count);
+	void (*write)(struct qcom_glink_pipe *glink_pipe,
+		      const void *hdr, size_t hlen,
+		      const void *data, size_t dlen);
+};
+
 struct rpm_toc {
 	__le32 magic;
 	__le32 count;
@@ -62,12 +78,12 @@ struct glink_msg {
 } __packed;
 
 struct glink_rpm_pipe {
+	struct qcom_glink_pipe native;
+
 	void __iomem *tail;
 	void __iomem *head;
 
 	void __iomem *fifo;
-
-	size_t length;
 };
 
 /**
@@ -107,8 +123,8 @@ struct qcom_glink {
 	struct mbox_client mbox_client;
 	struct mbox_chan *mbox_chan;
 
-	struct glink_rpm_pipe rx_pipe;
-	struct glink_rpm_pipe tx_pipe;
+	struct qcom_glink_pipe *rx_pipe;
+	struct qcom_glink_pipe *tx_pipe;
 
 	int irq;
 
@@ -215,9 +231,9 @@ static void qcom_glink_channel_release(struct kref *ref)
 	kfree(channel);
 }
 
-static size_t qcom_glink_rx_avail(struct qcom_glink *glink)
+static size_t glink_rpm_rx_avail(struct qcom_glink_pipe *glink_pipe)
 {
-	struct glink_rpm_pipe *pipe = &glink->rx_pipe;
+	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
 	unsigned int head;
 	unsigned int tail;
 
@@ -225,21 +241,26 @@ static size_t qcom_glink_rx_avail(struct qcom_glink *glink)
 	tail = readl(pipe->tail);
 
 	if (head < tail)
-		return pipe->length - tail + head;
+		return pipe->native.length - tail + head;
 	else
 		return head - tail;
 }
 
-static void qcom_glink_rx_peak(struct qcom_glink *glink,
+static size_t qcom_glink_rx_avail(struct qcom_glink *glink)
+{
+	return glink->rx_pipe->avail(glink->rx_pipe);
+}
+
+static void glink_rpm_rx_peak(struct qcom_glink_pipe *glink_pipe,
 			      void *data, size_t count)
 {
-	struct glink_rpm_pipe *pipe = &glink->rx_pipe;
+	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
 	unsigned int tail;
 	size_t len;
 
 	tail = readl(pipe->tail);
 
-	len = min_t(size_t, count, pipe->length - tail);
+	len = min_t(size_t, count, pipe->native.length - tail);
 	if (len) {
 		__ioread32_copy(data, pipe->fifo + tail,
 				len / sizeof(u32));
@@ -251,24 +272,35 @@ static void qcom_glink_rx_peak(struct qcom_glink *glink,
 	}
 }
 
-static void qcom_glink_rx_advance(struct qcom_glink *glink,
+static void qcom_glink_rx_peak(struct qcom_glink *glink,
+			       void *data, size_t count)
+{
+	glink->rx_pipe->peak(glink->rx_pipe, data, count);
+}
+
+static void glink_rpm_rx_advance(struct qcom_glink_pipe *glink_pipe,
 				 size_t count)
 {
-	struct glink_rpm_pipe *pipe = &glink->rx_pipe;
+	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
 	unsigned int tail;
 
 	tail = readl(pipe->tail);
 
 	tail += count;
-	if (tail >= pipe->length)
-		tail -= pipe->length;
+	if (tail >= pipe->native.length)
+		tail -= pipe->native.length;
 
 	writel(tail, pipe->tail);
 }
 
-static size_t qcom_glink_tx_avail(struct qcom_glink *glink)
+static void qcom_glink_rx_advance(struct qcom_glink *glink, size_t count)
+{
+	glink->rx_pipe->advance(glink->rx_pipe, count);
+}
+
+static size_t glink_rpm_tx_avail(struct qcom_glink_pipe *glink_pipe)
 {
-	struct glink_rpm_pipe *pipe = &glink->tx_pipe;
+	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
 	unsigned int head;
 	unsigned int tail;
 
@@ -276,19 +308,23 @@ static size_t qcom_glink_tx_avail(struct qcom_glink *glink)
 	tail = readl(pipe->tail);
 
 	if (tail <= head)
-		return pipe->length - head + tail;
+		return pipe->native.length - head + tail;
 	else
 		return tail - head;
 }
 
-static unsigned int qcom_glink_tx_write(struct qcom_glink *glink,
+static size_t qcom_glink_tx_avail(struct qcom_glink *glink)
+{
+	return glink->tx_pipe->avail(glink->tx_pipe);
+}
+
+static unsigned int glink_rpm_tx_write_one(struct glink_rpm_pipe *pipe,
 					   unsigned int head,
 					   const void *data, size_t count)
 {
-	struct glink_rpm_pipe *pipe = &glink->tx_pipe;
 	size_t len;
 
-	len = min_t(size_t, count, pipe->length - head);
+	len = min_t(size_t, count, pipe->native.length - head);
 	if (len) {
 		__iowrite32_copy(pipe->fifo + head, data,
 				 len / sizeof(u32));
@@ -300,23 +336,41 @@ static unsigned int qcom_glink_tx_write(struct qcom_glink *glink,
 	}
 
 	head += count;
-	if (head >= pipe->length)
-		head -= pipe->length;
+	if (head >= pipe->native.length)
+		head -= pipe->native.length;
 
 	return head;
 }
 
+static void glink_rpm_tx_write(struct qcom_glink_pipe *glink_pipe,
+			       const void *hdr, size_t hlen,
+			       const void *data, size_t dlen)
+{
+	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
+	unsigned int head;
+
+	head = readl(pipe->head);
+	head = glink_rpm_tx_write_one(pipe, head, hdr, hlen);
+	head = glink_rpm_tx_write_one(pipe, head, data, dlen);
+	writel(head, pipe->head);
+}
+
+static void qcom_glink_tx_write(struct qcom_glink *glink,
+				const void *hdr, size_t hlen,
+				const void *data, size_t dlen)
+{
+	glink->tx_pipe->write(glink->tx_pipe, hdr, hlen, data, dlen);
+}
+
 static int qcom_glink_tx(struct qcom_glink *glink,
 			 const void *hdr, size_t hlen,
 			const void *data, size_t dlen, bool wait)
 {
-	struct glink_rpm_pipe *pipe = &glink->tx_pipe;
-	unsigned int head;
 	unsigned int tlen = hlen + dlen;
 	int ret;
 
 	/* Reject packets that are too big */
-	if (tlen >= glink->tx_pipe.length)
+	if (tlen >= glink->tx_pipe->length)
 		return -EINVAL;
 
 	if (WARN(tlen % 8, "Unaligned TX request"))
@@ -335,10 +389,7 @@ static int qcom_glink_tx(struct qcom_glink *glink,
 		msleep(10);
 	}
 
-	head = readl(pipe->head);
-	head = qcom_glink_tx_write(glink, head, hdr, hlen);
-	head = qcom_glink_tx_write(glink, head, data, dlen);
-	writel(head, pipe->head);
+	qcom_glink_tx_write(glink, hdr, hlen, data, dlen);
 
 	mbox_send_message(glink->mbox_chan, NULL);
 	mbox_client_txdone(glink->mbox_chan, 0);
@@ -1075,14 +1126,14 @@ static int glink_rpm_parse_toc(struct device *dev,
 
 		switch (id) {
 		case RPM_RX_FIFO_ID:
-			rx->length = size;
+			rx->native.length = size;
 
 			rx->tail = msg_ram + offset;
 			rx->head = msg_ram + offset + sizeof(u32);
 			rx->fifo = msg_ram + offset + 2 * sizeof(u32);
 			break;
 		case RPM_TX_FIFO_ID:
-			tx->length = size;
+			tx->native.length = size;
 
 			tx->tail = msg_ram + offset;
 			tx->head = msg_ram + offset + sizeof(u32);
@@ -1107,6 +1158,8 @@ static int glink_rpm_parse_toc(struct device *dev,
 static int glink_rpm_probe(struct platform_device *pdev)
 {
 	struct qcom_glink *glink;
+	struct glink_rpm_pipe *rx_pipe;
+	struct glink_rpm_pipe *tx_pipe;
 	struct device_node *np;
 	void __iomem *msg_ram;
 	size_t msg_ram_size;
@@ -1121,6 +1174,11 @@ static int glink_rpm_probe(struct platform_device *pdev)
 
 	glink->dev = dev;
 
+	rx_pipe = devm_kzalloc(&pdev->dev, sizeof(*rx_pipe), GFP_KERNEL);
+	tx_pipe = devm_kzalloc(&pdev->dev, sizeof(*tx_pipe), GFP_KERNEL);
+	if (!rx_pipe || !tx_pipe)
+		return -ENOMEM;
+
 	mutex_init(&glink->tx_lock);
 	spin_lock_init(&glink->rx_lock);
 	INIT_LIST_HEAD(&glink->rx_queue);
@@ -1150,12 +1208,22 @@ static int glink_rpm_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	ret = glink_rpm_parse_toc(dev, msg_ram, msg_ram_size,
-				  &glink->rx_pipe, &glink->tx_pipe);
+				  rx_pipe, tx_pipe);
 	if (ret)
 		return ret;
 
-	writel(0, glink->tx_pipe.head);
-	writel(0, glink->rx_pipe.tail);
+	/* Pipe specific accessors */
+	rx_pipe->native.avail = glink_rpm_rx_avail;
+	rx_pipe->native.peak = glink_rpm_rx_peak;
+	rx_pipe->native.advance = glink_rpm_rx_advance;
+	tx_pipe->native.avail = glink_rpm_tx_avail;
+	tx_pipe->native.write = glink_rpm_tx_write;
+
+	glink->tx_pipe = &tx_pipe->native;
+	glink->rx_pipe = &rx_pipe->native;
+
+	writel(0, tx_pipe->head);
+	writel(0, rx_pipe->tail);
 
 	irq = platform_get_irq(pdev, 0);
 	ret = devm_request_irq(dev, irq,