RE: [PATCH 03/10] remoteproc: imx: use devm_ioremap

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

> Subject: Re: [PATCH 03/10] remoteproc: imx: use devm_ioremap
> 
> On Mon, Jul 27, 2020 at 06:28:20AM +0000, Peng Fan wrote:
> > Hi Oleksij,
> >
> > > Subject: Re: [PATCH 03/10] remoteproc: imx: use devm_ioremap
> > >
> > > On Fri, Jul 24, 2020 at 04:08:06PM +0800, Peng Fan wrote:
> > > > We might need to map an region multiple times, becaue the region
> > > > might be shared between remote processors, such i.MX8QM with dual
> M4 cores.
> > > > So use devm_ioremap, not devm_ioremap_resource.
> > >
> > > Can you please give an example of this kind of shared resources and
> > > how they should be handled by two separate devices?
> >
> > This is to share vdevbuffer space, there is a vdevbuffer in device
> > tree, it will be shared between M4_0 and M4_1.
> >
> > For the buffer, it is Linux DMA API will handle the space.
> 
> Why remoteproc need to care about it? If I see it correctly, from the linux
> perspective, it is one buffer and one driver is responsible for it. Or do I missing
> some thing?

We not have the vdev buffer in resource table, so I added in device tree, see below:

        imx8qm_cm40: imx8qm_cm4@0 {
                compatible = "fsl,imx8qm-cm4";
                rsc-da = <0x90000000>;
                mbox-names = "tx", "rx", "rxdb";
                mboxes = <&lsio_mu5 0 1
                          &lsio_mu5 1 1
                          &lsio_mu5 3 1>;
                mub-partition = <3>;
                memory-region = <&vdev0vring0>, <&vdev0vring1>, <&vdevbuffer>,
                                <&vdev1vring0>, <&vdev1vring1>;
                core-index = <0>;
                core-id = <IMX_SC_R_M4_0_PID0>;
                status = "okay";
                power-domains = <&pd IMX_SC_R_M4_0_PID0>,
                                <&pd IMX_SC_R_M4_0_MU_1A>;
        };

        imx8qm_cm41: imx8x_cm4@1 {
                compatible = "fsl,imx8qm-cm4";
                rsc-da = <0x90100000>;
                mbox-names = "tx", "rx", "rxdb";
                mboxes = <&lsio_mu6 0 1
                          &lsio_mu6 1 1
                          &lsio_mu6 3 1>;
                mub-partition = <4>;
                memory-region = <&vdev2vring0>, <&vdev2vring1>, <&vdevbuffer>,
                                <&vdev3vring0>, <&vdev3vring1>;
                core-index = <1>;
                core-id = <IMX_SC_R_M4_1_PID0>;
                status = "okay";
                power-domains = <&pd IMX_SC_R_M4_1_PID0>,
                                <&pd IMX_SC_R_M4_1_MU_1A>;
        };

                vdevbuffer: vdevbuffer {
                        compatible = "shared-dma-pool";
                        reg = <0 0x90400000 0 0x100000>;
                        no-map;
                };

I have the upper vdevbuffer node shared between M40 and M41 node.
The vdevbuffer will be used as virtio data buffer.

And I have the following in rproc_add_virtio_dev to share vdevbuffer:
        /* Try to find dedicated vdev buffer carveout */
        mem = rproc_find_carveout_by_name(rproc, "vdev%dbuffer", rvdev->index);
        if (!mem)
                mem = rproc_find_carveout_by_name(rproc, "vdevbuffer");


Hope this is clear.


Thanks,
Peng.

> 
> > Thanks,
> > Peng.
> >
> > >
> > > > Reviewed-by: Richard Zhu <hongxing.zhu@nxp.com>
> > > > Signed-off-by: Peng Fan <peng.fan@nxp.com>
> > > > ---
> > > >  drivers/remoteproc/imx_rproc.c | 5 +++--
> > > >  1 file changed, 3 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/drivers/remoteproc/imx_rproc.c
> > > > b/drivers/remoteproc/imx_rproc.c index 3b3904ebac75..82594a800a1b
> > > > 100644
> > > > --- a/drivers/remoteproc/imx_rproc.c
> > > > +++ b/drivers/remoteproc/imx_rproc.c
> > > > @@ -296,9 +296,10 @@ static int imx_rproc_addr_init(struct
> > > > imx_rproc
> > > *priv,
> > > >  		if (b >= IMX7D_RPROC_MEM_MAX)
> > > >  			break;
> > > >
> > > > -		priv->mem[b].cpu_addr =
> devm_ioremap_resource(&pdev->dev,
> > > &res);
> > > > +		/* Not use resource version, because we might share region*/
> > > > +		priv->mem[b].cpu_addr = devm_ioremap(&pdev->dev,
> res.start,
> > > > +resource_size(&res));
> > > >  		if (IS_ERR(priv->mem[b].cpu_addr)) {
> > > > -			dev_err(dev, "devm_ioremap_resource failed\n");
> > > > +			dev_err(dev, "devm_ioremap %pR failed\n", &res);
> > > >  			err = PTR_ERR(priv->mem[b].cpu_addr);
> > > >  			return err;
> > > >  		}
> > > > --
> > > > 2.16.4
> > > >
> > > >
> > >
> > > --
> > > Pengutronix e.K.                           |
> > > |
> > > Steuerwalder Str. 21                       |
> > > http://www.pengutronix.de/  |
> > > 31137 Hildesheim, Germany                  | Phone:
> > > +49-5121-206917-0    |
> > > Amtsgericht Hildesheim, HRA 2686           | Fax:
> > > +49-5121-206917-5555 |
> 
> --
> Pengutronix e.K.                           |
> |
> Steuerwalder Str. 21                       |
> http://www.pengutronix.de/  |
> 31137 Hildesheim, Germany                  | Phone:
> +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686           | Fax:
> +49-5121-206917-5555 |