RE: [PATCH V3 5/6] remoteproc: imx_rproc: support i.MX8QM

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

> Subject: Re: [PATCH V3 5/6] remoteproc: imx_rproc: support i.MX8QM
> 
> On Tue, May 17, 2022 at 02:49:36PM +0800, Peng Fan (OSS) wrote:
> > From: Peng Fan <peng.fan@nxp.com>
> >
> > Most logic are same as i.MX8QXP, but i.MX8QM has two general purpose
> > M4 cores, the two cores runs independently and they has different
> > resource id, different start address from SCFW view.
> >
> > Signed-off-by: Peng Fan <peng.fan@nxp.com>
> > ---
> >  drivers/remoteproc/imx_rproc.c | 41
> > +++++++++++++++++++++++++++++++---
> >  1 file changed, 38 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/remoteproc/imx_rproc.c
> > b/drivers/remoteproc/imx_rproc.c index 49cce9dd55c7..8326193c13d6
> > 100644
> > --- a/drivers/remoteproc/imx_rproc.c
> > +++ b/drivers/remoteproc/imx_rproc.c
> > @@ -3,6 +3,7 @@
> >   * Copyright (c) 2017 Pengutronix, Oleksij Rempel
> <kernel@pengutronix.de>
> >   */
> >
> > +#include <dt-bindings/firmware/imx/rsrc.h>
> >  #include <linux/arm-smccc.h>
> >  #include <linux/clk.h>
> >  #include <linux/err.h>
> > @@ -75,10 +76,13 @@ struct imx_rproc_mem {
> >  	size_t size;
> >  };
> >
> > -/* att flags */
> > +/* att flags: lower 16 bits specifying core, higher 16 bits for flags
> > +*/
> >  /* M4 own area. Can be mapped at probe */
> > -#define ATT_OWN		BIT(1)
> > -#define ATT_IOMEM	BIT(2)
> > +#define ATT_OWN         BIT(31)
> > +#define ATT_IOMEM       BIT(30)
> > +
> > +#define ATT_CORE_MASK   0xffff
> > +#define ATT_CORE(I)     BIT((I))
> >
> >  struct imx_rproc {
> >  	struct device			*dev;
> > @@ -99,6 +103,7 @@ struct imx_rproc {
> >  	u32				rsrc_id;	/* resource id */
> >  	u32				entry;		/* cpu start address */
> >  	int                             num_pd;
> > +	u32				core_index;
> >  	struct device                   **pd_dev;
> >  	struct device_link              **pd_dev_link;
> >  };
> > @@ -129,6 +134,19 @@ static const struct imx_rproc_att
> imx_rproc_att_imx93[] = {
> >  	{ 0xD0000000, 0xa0000000, 0x10000000, 0 },  };
> >
> > +static const struct imx_rproc_att imx_rproc_att_imx8qm[] = {
> > +	/* dev addr , sys addr  , size      , flags */
> > +	{ 0x08000000, 0x08000000, 0x10000000, 0},
> > +	/* TCML */
> > +	{ 0x1FFE0000, 0x34FE0000, 0x00020000, ATT_OWN | ATT_IOMEM |
> ATT_CORE(0)},
> > +	{ 0x1FFE0000, 0x38FE0000, 0x00020000, ATT_OWN | ATT_IOMEM |
> ATT_CORE(1)},
> > +	/* TCMU */
> > +	{ 0x20000000, 0x35000000, 0x00020000, ATT_OWN | ATT_IOMEM |
> ATT_CORE(0)},
> > +	{ 0x20000000, 0x39000000, 0x00020000, ATT_OWN | ATT_IOMEM |
> ATT_CORE(1)},
> > +	/* DDR (Data) */
> > +	{ 0x80000000, 0x80000000, 0x60000000, 0 }, };
> > +
> >  static const struct imx_rproc_att imx_rproc_att_imx8qxp[] = {
> >  	{ 0x08000000, 0x08000000, 0x10000000, 0 },
> >  	/* TCML/U */
> > @@ -279,6 +297,12 @@ static const struct imx_rproc_dcfg
> imx_rproc_cfg_imx8mq = {
> >  	.method		= IMX_RPROC_MMIO,
> >  };
> >
> > +static const struct imx_rproc_dcfg imx_rproc_cfg_imx8qm = {
> > +	.att            = imx_rproc_att_imx8qm,
> > +	.att_size       = ARRAY_SIZE(imx_rproc_att_imx8qm),
> > +	.method         = IMX_RPROC_SCU_API,
> > +};
> > +
> >  static const struct imx_rproc_dcfg imx_rproc_cfg_imx8qxp = {
> >  	.att		= imx_rproc_att_imx8qxp,
> >  	.att_size	= ARRAY_SIZE(imx_rproc_att_imx8qxp),
> > @@ -395,6 +419,11 @@ static int imx_rproc_da_to_sys(struct imx_rproc
> *priv, u64 da,
> >  	for (i = 0; i < dcfg->att_size; i++) {
> >  		const struct imx_rproc_att *att = &dcfg->att[i];
> >
> > +		if (att->flags & ATT_CORE_MASK) {
> > +			if (!((BIT(priv->core_index)) & (att->flags & ATT_CORE_MASK)))
> > +				continue;
> > +		}
> 
> This is very cryptic - I just spent 20 minutes looking at it and I'm still not sure I
> got the full meaning.  Please add enough comments to make things obvious
> on first read.

There are two generic M4 cores in i.MX8QM, so core_index is 0 for M4_0,
and 1 for M4_1.

In the memory mapping array:
        { 0x1FFE0000, 0x34FE0000, 0x00020000, ATT_OWN | ATT_IOMEM | ATT_CORE(0)},                   
        { 0x1FFE0000, 0x38FE0000, 0x00020000, ATT_OWN | ATT_IOMEM | ATT_CORE(1)},                   
        /* TCMU */                                                                                  
        { 0x20000000, 0x35000000, 0x00020000, ATT_OWN | ATT_IOMEM | ATT_CORE(0)},                   
        { 0x20000000, 0x39000000, 0x00020000, ATT_OWN | ATT_IOMEM | ATT_CORE(1)},

ATT_CORE(0) means it is for M4_0, ATT_CORE(1) for M4_1.

Back to this piece code:
                if (att->flags & ATT_CORE_MASK) {                                                   
                        if (!((BIT(priv->core_index)) & (att->flags & ATT_CORE_MASK)))              
                                continue;                                                           
                }

Taking M4_1 for example, priv->core_index is 1. So when it need translate an address with
ATT_CORE(X) flag, it should ignore ATT_CORE(0) entries. Hope this is clear. For adding
comments, how do you think:

/* Bypass the entries that not belong to the current remote core */

Thanks,
Peng.

> 
> I am done reviewing this patchset.
> 
> Thanks,
> Mathieu
> 
> 
> > +
> >  		if (da >= att->da && da + len < att->da + att->size) {
> >  			unsigned int offset = da - att->da;
> >
> > @@ -815,6 +844,11 @@ static int imx_rproc_detect_mode(struct
> imx_rproc *priv)
> >  			return ret;
> >  		}
> >
> > +		if (priv->rsrc_id == IMX_SC_R_M4_1_PID0)
> > +			priv->core_index = 1;
> > +		else
> > +			priv->core_index = 0;
> > +
> >  		/*
> >  		 * If Mcore resource is not owned by Acore partition, It is kicked by
> ROM,
> >  		 * and Linux could only do IPC with Mcore and nothing else.
> > @@ -1008,6 +1042,7 @@ static const struct of_device_id
> imx_rproc_of_match[] = {
> >  	{ .compatible = "fsl,imx8mn-cm7", .data = &imx_rproc_cfg_imx8mn },
> >  	{ .compatible = "fsl,imx8mp-cm7", .data = &imx_rproc_cfg_imx8mn },
> >  	{ .compatible = "fsl,imx8qxp-cm4", .data = &imx_rproc_cfg_imx8qxp },
> > +	{ .compatible = "fsl,imx8qm-cm4", .data = &imx_rproc_cfg_imx8qm },
> >  	{ .compatible = "fsl,imx8ulp-cm33", .data = &imx_rproc_cfg_imx8ulp },
> >  	{ .compatible = "fsl,imx93-cm33", .data = &imx_rproc_cfg_imx93 },
> >  	{},
> > --
> > 2.25.1
> >