Re: [PATCH V2 7/7] remoteproc: imx_proc: enable virtio/mailbox

From: Mathieu Poirier
Date: Mon Oct 19 2020 - 16:12:35 EST

On Sun, Sep 27, 2020 at 02:41:31PM +0800, Peng Fan wrote:
> Use virtio/mailbox to build connection between Remote Proccessors
> and Linux. Add delayed work to handle incoming messages.
>
> Reviewed-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> ---
> drivers/remoteproc/imx_rproc.c | 112 ++++++++++++++++++++++++++++++++-
> 1 file changed, 109 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
> index 0f69f3f745ab..c514d7ca7c81 100644
> --- a/drivers/remoteproc/imx_rproc.c
> +++ b/drivers/remoteproc/imx_rproc.c
> @@ -8,6 +8,7 @@
> #include <linux/interrupt.h>
> #include <linux/io.h>
> #include <linux/kernel.h>
> +#include <linux/mailbox_client.h>
> #include <linux/mfd/syscon.h>
> #include <linux/module.h>
> #include <linux/of_address.h>
> @@ -17,6 +18,8 @@
> #include <linux/regmap.h>
> #include <linux/remoteproc.h>
>
> +#include "remoteproc_internal.h"
> +
> #define IMX7D_SRC_SCR 0x0C
> #define IMX7D_ENABLE_M4 BIT(3)
> #define IMX7D_SW_M4P_RST BIT(2)
> @@ -88,6 +91,10 @@ 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 delayed_work rproc_work;
> };
>
> static const struct imx_rproc_att imx_rproc_att_imx8mq[] = {
> @@ -373,9 +380,30 @@ 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;
> + }
> +
> + mmsg = vqid << 16;

Please add a comment that explains the reason for the shift left.

> +
> + priv->cl.tx_tout = 100;

See my comment below on this.

> + 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,
> @@ -458,6 +486,70 @@ static void imx_rproc_memset(struct rproc *rproc, void *s, int c, size_t count)
> memset_io((void * __iomem)s, c, count);
> }
>
> +static void imx_rproc_vq_work(struct work_struct *work)
> +{
> + struct delayed_work *dwork = to_delayed_work(work);
> + struct imx_rproc *priv = container_of(dwork, 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;
> +
> + schedule_delayed_work(&(priv->rproc_work), 0);

What is the advantage of using a struct delayed_work if there is no delay? And
since schedule_delayed_work() is using the system_wq, you could simply declare a
struct work_struct and call queue_work() on it.

> +}
> +
> +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 = 0;
> +
> + 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 = 20;

What is the point of setting this here when it is set again in imx_rproc_kick()
to 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)) {
> + if (PTR_ERR(priv->tx_ch) == -EPROBE_DEFER)
> + return -EPROBE_DEFER;
> + ret = PTR_ERR(priv->tx_ch);
> + dev_dbg(cl->dev, "failed to request mbox tx chan, ret %d\n",
> + ret);
> + goto err_out;
> + }
> +
> + priv->rx_ch = mbox_request_channel_byname(cl, "rx");
> + if (IS_ERR(priv->rx_ch)) {
> + ret = PTR_ERR(priv->rx_ch);
> + dev_dbg(cl->dev, "failed to request mbox rx chan, ret %d\n",
> + ret);
> + goto err_out;
> + }

Where and when are the channels freed?

Thanks,
Mathieu

> +
> + return ret;
> +
> +err_out:
> + if (!IS_ERR(priv->tx_ch))
> + mbox_free_channel(priv->tx_ch);
> + if (!IS_ERR(priv->rx_ch))
> + mbox_free_channel(priv->rx_ch);
> +
> + return ret;
> +}
> +
> static int imx_rproc_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> @@ -501,17 +593,24 @@ static int imx_rproc_probe(struct platform_device *pdev)
>
> dev_set_drvdata(dev, rproc);
>
> + ret = imx_rproc_xtr_mbox_init(rproc);
> + if (ret) {
> + if (ret == -EPROBE_DEFER)
> + goto err_put_rproc;
> + /* mbox is optional, so not fail here */
> + }
> +
> 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;
> }
>
> /*
> @@ -521,9 +620,11 @@ 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_DELAYED_WORK(&(priv->rproc_work), imx_rproc_vq_work);
> +
> ret = rproc_add(rproc);
> if (ret) {
> dev_err(dev, "rproc_add failed\n");
> @@ -534,6 +635,11 @@ static int imx_rproc_probe(struct platform_device *pdev)
>
> err_put_clk:
> clk_disable_unprepare(priv->clk);
> +err_put_mbox:
> + if (!IS_ERR(priv->tx_ch))
> + mbox_free_channel(priv->tx_ch);
> + if (!IS_ERR(priv->rx_ch))
> + mbox_free_channel(priv->rx_ch);
> err_put_rproc:
> rproc_free(rproc);
>
> --
> 2.28.0
>