Re: [PATCH v5] remoteproc: imx_dsp_rproc: add custom memory copy implementation for i.MX DSP Cores

[Mathieu Poirier]

On Wed, Mar 01, 2023 at 11:49:16AM -0700, Mathieu Poirier wrote:
> Hi Iuliana,
> 
> On Tue, Feb 21, 2023 at 07:03:56PM +0200, Iuliana Prodan (OSS) wrote:
> > From: Iuliana Prodan <iuliana.prodan@xxxxxxx>
> > 
> > The IRAM is part of the HiFi DSP.
> > According to hardware specification only 32-bits write are allowed
> > otherwise we get a Kernel panic.
> > 
> > Therefore add a custom memory copy and memset functions to deal with
> > the above restriction.
> > 
> > Signed-off-by: Iuliana Prodan <iuliana.prodan@xxxxxxx>
> > ---
> > Changes since v4
> > - use GENMASK;
> > - s/ioread32/readl;
> > - s/iowrite32/writel;
> > - use for loop with writel instead of __iowrite32_copy;
> > - update multi-line comment format.
> > 
> 
> This looks good now.  I will queue this on March 13th when 6.3-rc2 is out.
>

And out of curiosity, are the remote processors handled by imx_rproc.c also have
the same 32-bit write constraints?  If so, it would be nice to have a patch that
fixes that as well.  In such a case, imx_dsp_rproc_memcpy() and
imx_dsp_rproc_memset() should be renamed to something more generic and re-used
in imx_rproc.c.

> Thanks,
> Mathieu
> 
> > Changes since v3
> > - remove Reported-by
> > 
> > Changes since v2
> > - fix warning "cast from pointer to integer of different size"
> > reported by kernel test robot.
> > 
> > Changes since v1
> > - added missing check for cases when the memory slot is bigger than the file size;
> > - added a custom memset function
> > - removed is_iomem flag since is not used here
> > - updated custom memcpy function to avoid reading after end of source
> > ---
> >  drivers/remoteproc/imx_dsp_rproc.c | 187 ++++++++++++++++++++++++++++-
> >  1 file changed, 186 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/remoteproc/imx_dsp_rproc.c b/drivers/remoteproc/imx_dsp_rproc.c
> > index 81d3a01e1444..dcbb957bc7ac 100644
> > --- a/drivers/remoteproc/imx_dsp_rproc.c
> > +++ b/drivers/remoteproc/imx_dsp_rproc.c
> > @@ -739,6 +739,191 @@ static void imx_dsp_rproc_kick(struct rproc *rproc, int vqid)
> >  		dev_err(dev, "%s: failed (%d, err:%d)\n", __func__, vqid, err);
> >  }
> >  
> > +/*
> > + * Custom memory copy implementation for i.MX DSP Cores
> > + *
> > + * The IRAM is part of the HiFi DSP.
> > + * According to hw specs only 32-bits writes are allowed.
> > + */
> > +static int imx_dsp_rproc_memcpy(void *dest, const void *src, size_t size)
> > +{
> > +	const u8 *src_byte = src;
> > +	const u32 *source = src;
> > +	u32 affected_mask;
> > +	u32 *dst = dest;
> > +	int i, q, r;
> > +	u32 tmp;
> > +
> > +	/* destination must be 32bit aligned */
> > +	if (!IS_ALIGNED((uintptr_t)dest, 4))
> > +		return -EINVAL;
> > +
> > +	q = size / 4;
> > +	r = size % 4;
> > +
> > +	/* copy data in units of 32 bits at a time */
> > +	for (i = 0; i < q; i++)
> > +		writel(source[i], &dst[i]);
> > +
> > +	if (r) {
> > +		affected_mask = GENMASK(8 * r, 0);
> > +
> > +		/*
> > +		 * first read the 32bit data of dest, then change affected
> > +		 * bytes, and write back to dest.
> > +		 * For unaffected bytes, it should not be changed
> > +		 */
> > +		tmp = readl(dest + q * 4);
> > +		tmp &= ~affected_mask;
> > +
> > +		/* avoid reading after end of source */
> > +		for (i = 0; i < r; i++)
> > +			tmp |= (src_byte[q * 4 + i] << (8 * i));
> > +
> > +		writel(tmp, dest + q * 4);
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +/*
> > + * Custom memset implementation for i.MX DSP Cores
> > + *
> > + * The IRAM is part of the HiFi DSP.
> > + * According to hw specs only 32-bits writes are allowed.
> > + */
> > +static int imx_dsp_rproc_memset(void *addr, u8 value, size_t size)
> > +{
> > +	u32 tmp_val = value;
> > +	u32 *tmp_dst = addr;
> > +	u32 affected_mask;
> > +	int q, r;
> > +	u32 tmp;
> > +
> > +	/* destination must be 32bit aligned */
> > +	if (!IS_ALIGNED((uintptr_t)addr, 4))
> > +		return -EINVAL;
> > +
> > +	tmp_val |= tmp_val << 8;
> > +	tmp_val |= tmp_val << 16;
> > +
> > +	q = size / 4;
> > +	r = size % 4;
> > +
> > +	while (q--)
> > +		writel(tmp_val, tmp_dst++);
> > +
> > +	if (r) {
> > +		affected_mask = GENMASK(8 * r, 0);
> > +
> > +		/*
> > +		 * first read the 32bit data of addr, then change affected
> > +		 * bytes, and write back to addr.
> > +		 * For unaffected bytes, it should not be changed
> > +		 */
> > +		tmp = readl(tmp_dst);
> > +		tmp &= ~affected_mask;
> > +
> > +		tmp |= (tmp_val & affected_mask);
> > +		writel(tmp, tmp_dst);
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +/**
> > + * imx_dsp_rproc_elf_load_segments() - load firmware segments to memory
> > + * @rproc: remote processor which will be booted using these fw segments
> > + * @fw: the ELF firmware image
> > + *
> > + * This function loads the firmware segments to memory, where the remote
> > + * processor expects them.
> > + *
> > + * Return: 0 on success and an appropriate error code otherwise
> > + */
> > +static int imx_dsp_rproc_elf_load_segments(struct rproc *rproc, const struct firmware *fw)
> > +{
> > +	struct device *dev = &rproc->dev;
> > +	const void *ehdr, *phdr;
> > +	int i, ret = 0;
> > +	u16 phnum;
> > +	const u8 *elf_data = fw->data;
> > +	u8 class = fw_elf_get_class(fw);
> > +	u32 elf_phdr_get_size = elf_size_of_phdr(class);
> > +
> > +	ehdr = elf_data;
> > +	phnum = elf_hdr_get_e_phnum(class, ehdr);
> > +	phdr = elf_data + elf_hdr_get_e_phoff(class, ehdr);
> > +
> > +	/* go through the available ELF segments */
> > +	for (i = 0; i < phnum; i++, phdr += elf_phdr_get_size) {
> > +		u64 da = elf_phdr_get_p_paddr(class, phdr);
> > +		u64 memsz = elf_phdr_get_p_memsz(class, phdr);
> > +		u64 filesz = elf_phdr_get_p_filesz(class, phdr);
> > +		u64 offset = elf_phdr_get_p_offset(class, phdr);
> > +		u32 type = elf_phdr_get_p_type(class, phdr);
> > +		void *ptr;
> > +
> > +		if (type != PT_LOAD || !memsz)
> > +			continue;
> > +
> > +		dev_dbg(dev, "phdr: type %d da 0x%llx memsz 0x%llx filesz 0x%llx\n",
> > +			type, da, memsz, filesz);
> > +
> > +		if (filesz > memsz) {
> > +			dev_err(dev, "bad phdr filesz 0x%llx memsz 0x%llx\n",
> > +				filesz, memsz);
> > +			ret = -EINVAL;
> > +			break;
> > +		}
> > +
> > +		if (offset + filesz > fw->size) {
> > +			dev_err(dev, "truncated fw: need 0x%llx avail 0x%zx\n",
> > +				offset + filesz, fw->size);
> > +			ret = -EINVAL;
> > +			break;
> > +		}
> > +
> > +		if (!rproc_u64_fit_in_size_t(memsz)) {
> > +			dev_err(dev, "size (%llx) does not fit in size_t type\n",
> > +				memsz);
> > +			ret = -EOVERFLOW;
> > +			break;
> > +		}
> > +
> > +		/* grab the kernel address for this device address */
> > +		ptr = rproc_da_to_va(rproc, da, memsz, NULL);
> > +		if (!ptr) {
> > +			dev_err(dev, "bad phdr da 0x%llx mem 0x%llx\n", da,
> > +				memsz);
> > +			ret = -EINVAL;
> > +			break;
> > +		}
> > +
> > +		/* put the segment where the remote processor expects it */
> > +		if (filesz) {
> > +			ret = imx_dsp_rproc_memcpy(ptr, elf_data + offset, filesz);
> > +			if (ret) {
> > +				dev_err(dev, "memory copy failed for da 0x%llx memsz 0x%llx\n",
> > +					da, memsz);
> > +				break;
> > +			}
> > +		}
> > +
> > +		/* zero out remaining memory for this segment */
> > +		if (memsz > filesz) {
> > +			ret = imx_dsp_rproc_memset(ptr + filesz, 0, memsz - filesz);
> > +			if (ret) {
> > +				dev_err(dev, "memset failed for da 0x%llx memsz 0x%llx\n",
> > +					da, memsz);
> > +				break;
> > +			}
> > +		}
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> >  static int imx_dsp_rproc_parse_fw(struct rproc *rproc, const struct firmware *fw)
> >  {
> >  	if (rproc_elf_load_rsc_table(rproc, fw))
> > @@ -753,7 +938,7 @@ static const struct rproc_ops imx_dsp_rproc_ops = {
> >  	.start		= imx_dsp_rproc_start,
> >  	.stop		= imx_dsp_rproc_stop,
> >  	.kick		= imx_dsp_rproc_kick,
> > -	.load		= rproc_elf_load_segments,
> > +	.load		= imx_dsp_rproc_elf_load_segments,
> >  	.parse_fw	= imx_dsp_rproc_parse_fw,
> >  	.sanity_check	= rproc_elf_sanity_check,
> >  	.get_boot_addr	= rproc_elf_get_boot_addr,
> > -- 
> > 2.17.1
> >