RE: [PATCH V3 7/7] remoteproc: imx_proc: enable virtio/mailbox

[Peng Fan <peng.fan@nxp.com>]

> Subject: Re: [PATCH V3 7/7] remoteproc: imx_proc: enable virtio/mailbox
> 
> On Fri 04 Dec 01:40 CST 2020, Peng Fan (OSS) wrote:
> 
> > From: Peng Fan <peng.fan@nxp.com>
> >
> > 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>
> > Signed-off-by: Peng Fan <peng.fan@nxp.com>
> > ---
> >  drivers/remoteproc/imx_rproc.c | 133
> > ++++++++++++++++++++++++++++++++-
> >  1 file changed, 130 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/remoteproc/imx_rproc.c
> > b/drivers/remoteproc/imx_rproc.c index afa650610996..584584a00921
> > 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>
> > @@ -16,6 +17,9 @@
> >  #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)
> > @@ -88,6 +92,11 @@ 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[] = { @@
> > -369,9 +378,33 @@ 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,
> > @@ -454,6 +487,77 @@ 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 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 = 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 = 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);
> 
> This is worse than a dev_dbg(), something is actually wrong.
> Also there's no point in jumping to err_out here, because tx_ch is
> IS_ERR() so we're going to skip the first part and rx_ch is not IS_ERR() so
> you're going to call mbox_free_channel(NULL) and then return.
> 
> So just replace this entire block with:
> 
> 		return dev_err_probe(dev, PTR_ERR(priv->ch_ch),
> 				     "failed to request tx mailbox channel: %d\n",
> 				     ret);

Yeah. Thanks.

> 
> 
> > +		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;
> 
> 		mbox_free_channel(priv->tx_ch);
> 		return dev_err_probe(dev, PTR_ERR(priv->ch_ch),
> 				     "failed to request rx mailbox channel: %d\n",
> 				     ret);
> 
> > +	}
> > +
> > +	return ret;
> 
> ret is 0 here.

Yes.

> 
> > +
> > +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 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;
> > @@ -496,18 +600,31 @@ 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) {
> > +		if (ret == -EPROBE_DEFER)
> > +			goto err_put_wkq;
> > +		/* mbox is optional, so not fail here */
> 
> imx_rproc_xtr_mbox_init() returns 0 if no mbox was specified, that means
> that in all cases that we reach here mailboxes where specified but an error
> occurred. You should not ignore this.

ok, fix in v4.

> 
> > +	}
> >
> >  	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;
> >  	}
> >
> >  	/*
> > @@ -517,9 +634,11 @@ 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"); @@ -530,6 +649,13 @@ 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))
> 
> With above changes you won't get here with IS_ERR(tx_ch) || IS_ERR(rx_ch),
> so you can safely remove the conditionals and just call mbox_free_channel().


Yes.

After we agree on the new method of patch 1/7, I'll post out v4.

Thanks,
Peng.

> 
> Regards,
> Bjorn
> 
> > +		mbox_free_channel(priv->tx_ch);
> > +	if (!IS_ERR(priv->rx_ch))
> > +		mbox_free_channel(priv->rx_ch);
> > +err_put_wkq:
> > +	destroy_workqueue(priv->workqueue);
> >  err_put_rproc:
> >  	rproc_free(rproc);
> >
> > @@ -542,6 +668,7 @@ static int imx_rproc_remove(struct platform_device
> *pdev)
> >  	struct imx_rproc *priv = rproc->priv;
> >
> >  	clk_disable_unprepare(priv->clk);
> > +	imx_rproc_free_mbox(rproc);
> >  	rproc_del(rproc);
> >  	rproc_free(rproc);
> >
> > --
> > 2.28.0
> >