Re: [PATCH v2 2/3] remoteproc: imx_rproc: mailbox support

From: Mathieu Poirier
Date: Tue Apr 14 2020 - 13:20:15 EST


On Mon, Apr 06, 2020 at 02:33:09PM +0300, nikita.shubin@xxxxxxxxxxx wrote:
> Add support for mailboxes to imx_rproc
>
> Signed-off-by: Nikita Shubin <NShubin@xxxxxxxxxx>
> ---
> drivers/remoteproc/Kconfig | 2 +
> drivers/remoteproc/imx_rproc.c | 142 ++++++++++++++++++++++++++++++++-
> 2 files changed, 143 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> index 94afdde4bc9f..02d23a54c9cf 100644
> --- a/drivers/remoteproc/Kconfig
> +++ b/drivers/remoteproc/Kconfig
> @@ -17,6 +17,8 @@ if REMOTEPROC
> config IMX_REMOTEPROC
> tristate "IMX6/7 remoteproc support"
> depends on ARCH_MXC
> + select MAILBOX
> + select IMX_MBOX
> help
> Say y here to support iMX's remote processors (Cortex M4
> on iMX7D) via the remote processor framework.
> diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
> index bebc58d0f711..d2bede4ccb70 100644
> --- a/drivers/remoteproc/imx_rproc.c
> +++ b/drivers/remoteproc/imx_rproc.c
> @@ -14,6 +14,9 @@
> #include <linux/platform_device.h>
> #include <linux/regmap.h>
> #include <linux/remoteproc.h>
> +#include <linux/mailbox_client.h>
> +
> +#include "remoteproc_internal.h"
>
> #define IMX7D_SRC_SCR 0x0C
> #define IMX7D_ENABLE_M4 BIT(3)
> @@ -47,6 +50,12 @@
>
> #define IMX_BOOT_PC 0x4
>
> +#define IMX_MBOX_NB_VQ 2
> +#define IMX_MBOX_NB_MBX 2

Please align this.

> +
> +#define IMX_MBX_VQ0 "vq0"
> +#define IMX_MBX_VQ1 "vq1"
> +
> /**
> * struct imx_rproc_mem - slim internal memory structure
> * @cpu_addr: MPU virtual address of the memory region
> @@ -80,6 +89,14 @@ struct imx_rproc_dcfg {
> size_t att_size;
> };
>
> +struct imx_mbox {
> + const unsigned char name[10];
> + struct mbox_chan *chan;
> + struct mbox_client client;
> + struct work_struct vq_work;
> + int vq_id;
> +};
> +
> struct imx_rproc {
> struct device *dev;
> struct regmap *regmap;
> @@ -88,6 +105,8 @@ struct imx_rproc {
> struct imx_rproc_mem mem[IMX7D_RPROC_MEM_MAX];
> struct clk *clk;
> void __iomem *bootreg;
> + struct imx_mbox mb[IMX_MBOX_NB_MBX];
> + struct workqueue_struct *workqueue;
> };
>
> static const struct imx_rproc_att imx_rproc_att_imx7d[] = {
> @@ -251,10 +270,118 @@ static void *imx_rproc_da_to_va(struct rproc *rproc, u64 da, int len)
> return va;
> }
>
> +static void imx_rproc_mb_vq_work(struct work_struct *work)
> +{
> + struct imx_mbox *mb = container_of(work, struct imx_mbox, vq_work);
> + struct rproc *rproc = dev_get_drvdata(mb->client.dev);
> +
> + if (rproc_vq_interrupt(rproc, mb->vq_id) == IRQ_NONE)
> + dev_dbg(&rproc->dev, "no message found in vq%d\n", mb->vq_id);
> +}
> +
> +static void imx_rproc_mb_callback(struct mbox_client *cl, void *data)
> +{
> + struct rproc *rproc = dev_get_drvdata(cl->dev);
> + struct imx_mbox *mb = container_of(cl, struct imx_mbox, client);
> + struct imx_rproc *ddata = rproc->priv;
> +
> + queue_work(ddata->workqueue, &mb->vq_work);
> +}
> +
> +static const struct imx_mbox imx_rproc_mbox[IMX_MBOX_NB_MBX] = {
> + {
> + .name = IMX_MBX_VQ0,
> + .vq_id = 0,
> + .client = {
> + .rx_callback = imx_rproc_mb_callback,
> + .tx_block = false,
> + },
> + },
> + {
> + .name = IMX_MBX_VQ1,
> + .vq_id = 1,
> + .client = {
> + .rx_callback = imx_rproc_mb_callback,
> + .tx_block = false,
> + },
> + },
> +};
> +
> +static void imx_rproc_request_mbox(struct rproc *rproc)
> +{
> + struct imx_rproc *ddata = rproc->priv;
> + struct device *dev = &rproc->dev;
> + unsigned int i;
> + const unsigned char *name;
> + struct mbox_client *cl;
> +
> + /* Initialise mailbox structure table */
> + memcpy(ddata->mb, imx_rproc_mbox, sizeof(imx_rproc_mbox));
> +
> + for (i = 0; i < IMX_MBOX_NB_MBX; i++) {
> + name = ddata->mb[i].name;
> +
> + cl = &ddata->mb[i].client;
> + cl->dev = dev->parent;
> +
> + ddata->mb[i].chan = mbox_request_channel_byname(cl, name);
> +
> + dev_dbg(dev, "%s: name=%s, idx=%u\n",
> + __func__, name, ddata->mb[i].vq_id);
> +
> + if (IS_ERR(ddata->mb[i].chan)) {
> + dev_warn(dev, "cannot get %s mbox\n", name);
> + ddata->mb[i].chan = NULL;

If the mailbox isn't ready this driver will fail without a chance of recovery.
Since most of the code in this patch is a carbon copy of the implementation
found in stm32_proc.c, I suggest you do the same as they did in
stm32_rproc_request_mbox() and privision for cases where requesting a channel
returns -EPROBE_DEFER.

> + }
> +
> + if (ddata->mb[i].vq_id >= 0)
> + INIT_WORK(&ddata->mb[i].vq_work, imx_rproc_mb_vq_work);
> + }
> +}
> +
> +static void imx_rproc_free_mbox(struct rproc *rproc)
> +{
> + struct imx_rproc *ddata = rproc->priv;
> + unsigned int i;
> +
> + dev_dbg(&rproc->dev, "%s: %d boxes\n",
> + __func__, ARRAY_SIZE(ddata->mb));
> +
> + for (i = 0; i < ARRAY_SIZE(ddata->mb); i++) {
> + if (ddata->mb[i].chan)
> + mbox_free_channel(ddata->mb[i].chan);
> + ddata->mb[i].chan = NULL;
> + }
> +}
> +
> +static void imx_rproc_kick(struct rproc *rproc, int vqid)
> +{
> + struct imx_rproc *ddata = rproc->priv;
> + unsigned int i;
> + int err;
> +
> + if (WARN_ON(vqid >= IMX_MBOX_NB_VQ))
> + return;
> +
> + for (i = 0; i < IMX_MBOX_NB_MBX; i++) {
> + if (vqid != ddata->mb[i].vq_id)
> + continue;
> + if (!ddata->mb[i].chan)
> + return;
> + dev_dbg(&rproc->dev, "sending message : vqid = %d\n", vqid);
> + err = mbox_send_message(ddata->mb[i].chan, &vqid);
> + if (err < 0)
> + dev_err(&rproc->dev, "%s: failed (%s, err:%d)\n",
> + __func__, ddata->mb[i].name, err);
> + return;
> + }
> +}
> +
> static const struct rproc_ops imx_rproc_ops = {
> .start = imx_rproc_start,
> .stop = imx_rproc_stop,
> .da_to_va = imx_rproc_da_to_va,
> + .kick = imx_rproc_kick,
> .get_boot_addr = rproc_elf_get_boot_addr,
> };
>
> @@ -384,14 +511,26 @@ static int imx_rproc_probe(struct platform_device *pdev)
> goto err_put_rproc;
> }
>
> + priv->workqueue = create_workqueue(dev_name(dev));
> + if (!priv->workqueue) {
> + dev_err(dev, "cannot create workqueue\n");
> + ret = -ENOMEM;
> + goto err_put_clk;
> + }
> +
> + imx_rproc_request_mbox(rproc);
> +
> ret = rproc_add(rproc);
> if (ret) {
> dev_err(dev, "rproc_add failed\n");
> - goto err_put_clk;
> + goto err_free_mb;
> }
>
> return 0;
>
> +err_free_mb:
> + imx_rproc_free_mbox(rproc);
> + destroy_workqueue(priv->workqueue);
> err_put_clk:
> clk_disable_unprepare(priv->clk);
> err_put_rproc:
> @@ -407,6 +546,7 @@ static int imx_rproc_remove(struct platform_device *pdev)
>
> clk_disable_unprepare(priv->clk);
> rproc_del(rproc);
> + imx_rproc_free_mbox(rproc);

I have no issues with people reusing code already found in the kernel - in fact
I encourage it because it makes reviewing patches much easier. On the flip side
you have to give credit where it is due. Here adding a line in the changelog
that mentions where you took your inspiration from will be much appreciated.

Thanks,
Mathieu

> rproc_free(rproc);
>
> return 0;
> --
> 2.25.1
>