remoteproc: imx_proc: enable virtio/mailbox

Use virtio/mailbox to build connection between Remote Proccessors
and Linux. Add work queue to handle incoming messages.

Reviewed-by: Richard Zhu <hongxing.zhu@nxp.com>
Reviewed-by: Mathieu Poirier <mathieu.poirer@linaro.org>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/1615029865-23312-11-git-send-email-peng.fan@oss.nxp.com
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/remoteproc/imx_rproc.c

@@ -7,6 +7,7 @@
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
+#include <linux/mailbox_client.h>
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
@@ -15,6 +16,9 @@
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/remoteproc.h>
+#include <linux/workqueue.h>
+
+#include "remoteproc_internal.h"
 
 #define IMX7D_SRC_SCR			0x0C
 #define IMX7D_ENABLE_M4			BIT(3)
@@ -86,6 +90,11 @@ struct imx_rproc {
 	const struct imx_rproc_dcfg	*dcfg;
 	struct imx_rproc_mem		mem[IMX7D_RPROC_MEM_MAX];
 	struct clk			*clk;
+	struct mbox_client		cl;
+	struct mbox_chan		*tx_ch;
+	struct mbox_chan		*rx_ch;
+	struct work_struct		rproc_work;
+	struct workqueue_struct		*workqueue;
 };
 
 static const struct imx_rproc_att imx_rproc_att_imx8mq[] = {
@@ -366,9 +375,33 @@ static int imx_rproc_parse_fw(struct rproc *rproc, const struct firmware *fw)
 	return 0;
 }
 
+static void imx_rproc_kick(struct rproc *rproc, int vqid)
+{
+	struct imx_rproc *priv = rproc->priv;
+	int err;
+	__u32 mmsg;
+
+	if (!priv->tx_ch) {
+		dev_err(priv->dev, "No initialized mbox tx channel\n");
+		return;
+	}
+
+	/*
+	 * Send the index of the triggered virtqueue as the mu payload.
+	 * Let remote processor know which virtqueue is used.
+	 */
+	mmsg = vqid << 16;
+
+	err = mbox_send_message(priv->tx_ch, (void *)&mmsg);
+	if (err < 0)
+		dev_err(priv->dev, "%s: failed (%d, err:%d)\n",
+			__func__, vqid, err);
+}
+
 static const struct rproc_ops imx_rproc_ops = {
 	.start		= imx_rproc_start,
 	.stop		= imx_rproc_stop,
+	.kick		= imx_rproc_kick,
 	.da_to_va       = imx_rproc_da_to_va,
 	.load		= rproc_elf_load_segments,
 	.parse_fw	= imx_rproc_parse_fw,
@@ -444,6 +477,66 @@ static int imx_rproc_addr_init(struct imx_rproc *priv,
 	return 0;
 }
 
+static void imx_rproc_vq_work(struct work_struct *work)
+{
+	struct imx_rproc *priv = container_of(work, struct imx_rproc,
+					      rproc_work);
+
+	rproc_vq_interrupt(priv->rproc, 0);
+	rproc_vq_interrupt(priv->rproc, 1);
+}
+
+static void imx_rproc_rx_callback(struct mbox_client *cl, void *msg)
+{
+	struct rproc *rproc = dev_get_drvdata(cl->dev);
+	struct imx_rproc *priv = rproc->priv;
+
+	queue_work(priv->workqueue, &priv->rproc_work);
+}
+
+static int imx_rproc_xtr_mbox_init(struct rproc *rproc)
+{
+	struct imx_rproc *priv = rproc->priv;
+	struct device *dev = priv->dev;
+	struct mbox_client *cl;
+	int ret;
+
+	if (!of_get_property(dev->of_node, "mbox-names", NULL))
+		return 0;
+
+	cl = &priv->cl;
+	cl->dev = dev;
+	cl->tx_block = true;
+	cl->tx_tout = 100;
+	cl->knows_txdone = false;
+	cl->rx_callback = imx_rproc_rx_callback;
+
+	priv->tx_ch = mbox_request_channel_byname(cl, "tx");
+	if (IS_ERR(priv->tx_ch)) {
+		ret = PTR_ERR(priv->tx_ch);
+		return dev_err_probe(cl->dev, ret,
+				     "failed to request tx mailbox channel: %d\n", ret);
+	}
+
+	priv->rx_ch = mbox_request_channel_byname(cl, "rx");
+	if (IS_ERR(priv->rx_ch)) {
+		mbox_free_channel(priv->tx_ch);
+		ret = PTR_ERR(priv->rx_ch);
+		return dev_err_probe(cl->dev, ret,
+				     "failed to request rx mailbox channel: %d\n", ret);
+	}
+
+	return 0;
+}
+
+static void imx_rproc_free_mbox(struct rproc *rproc)
+{
+	struct imx_rproc *priv = rproc->priv;
+
+	mbox_free_channel(priv->tx_ch);
+	mbox_free_channel(priv->rx_ch);
+}
+
 static int imx_rproc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -481,18 +574,28 @@ static int imx_rproc_probe(struct platform_device *pdev)
 	priv->dev = dev;
 
 	dev_set_drvdata(dev, rproc);
+	priv->workqueue = create_workqueue(dev_name(dev));
+	if (!priv->workqueue) {
+		dev_err(dev, "cannot create workqueue\n");
+		ret = -ENOMEM;
+		goto err_put_rproc;
+	}
+
+	ret = imx_rproc_xtr_mbox_init(rproc);
+	if (ret)
+		goto err_put_wkq;
 
 	ret = imx_rproc_addr_init(priv, pdev);
 	if (ret) {
 		dev_err(dev, "failed on imx_rproc_addr_init\n");
-		goto err_put_rproc;
+		goto err_put_mbox;
 	}
 
 	priv->clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(priv->clk)) {
 		dev_err(dev, "Failed to get clock\n");
 		ret = PTR_ERR(priv->clk);
-		goto err_put_rproc;
+		goto err_put_mbox;
 	}
 
 	/*
@@ -502,9 +605,11 @@ static int imx_rproc_probe(struct platform_device *pdev)
 	ret = clk_prepare_enable(priv->clk);
 	if (ret) {
 		dev_err(&rproc->dev, "Failed to enable clock\n");
-		goto err_put_rproc;
+		goto err_put_mbox;
 	}
 
+	INIT_WORK(&priv->rproc_work, imx_rproc_vq_work);
+
 	ret = rproc_add(rproc);
 	if (ret) {
 		dev_err(dev, "rproc_add failed\n");
@@ -515,6 +620,10 @@ static int imx_rproc_probe(struct platform_device *pdev)
 
 err_put_clk:
 	clk_disable_unprepare(priv->clk);
+err_put_mbox:
+	imx_rproc_free_mbox(rproc);
+err_put_wkq:
+	destroy_workqueue(priv->workqueue);
 err_put_rproc:
 	rproc_free(rproc);
 
@@ -528,6 +637,7 @@ static int imx_rproc_remove(struct platform_device *pdev)
 
 	clk_disable_unprepare(priv->clk);
 	rproc_del(rproc);
+	imx_rproc_free_mbox(rproc);
 	rproc_free(rproc);
 
 	return 0;