On Fri, Jan 27, 2023 at 05:22:45PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@xxxxxxx>
>
> The i.MX8M Cortex-M core not has ROM. It has a requirement is
> the stack, pc value should be set in address 0 and 4 from the view of
> itself. From Cortex-A core view, the region is at TCML start address.
>
> The stack and pc value are the first two words stored in section
> ".interrupts" of the firmware, and the section is the first section in
> the firmware.
>
> When the firmware is built to run in TCML, there is no issue, because
> when copying elf segments, the first two words are copied to TCML also.
>
> However when the firmware is built ro run in DDR, the first two words
> are not copied to TCML start address.
>
> This patch is to find the ".interrupts" section, read out the first
> two words and write to TCML start address at offset 0 and 4.
>
> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> ---
> drivers/remoteproc/imx_rproc.c | 37 +++++++++++++++++++++++++++++++++-
> 1 file changed, 36 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
> index 295e0e0e869a..f5ee0c9bb09d 100644
> --- a/drivers/remoteproc/imx_rproc.c
> +++ b/drivers/remoteproc/imx_rproc.c
> @@ -7,6 +7,7 @@
> #include <linux/arm-smccc.h>
> #include <linux/clk.h>
> #include <linux/err.h>
> +#include <linux/firmware.h>
> #include <linux/firmware/imx/sci.h>
> #include <linux/interrupt.h>
> #include <linux/kernel.h>
> @@ -23,6 +24,7 @@
> #include <linux/workqueue.h>
>
> #include "imx_rproc.h"
> +#include "remoteproc_elf_helpers.h"
> #include "remoteproc_internal.h"
>
> #define IMX7D_SRC_SCR 0x0C
> @@ -634,6 +636,39 @@ static struct resource_table *imx_rproc_get_loaded_rsc_table(struct rproc *rproc
> return (struct resource_table __force *)priv->rsc_table;
> }
>
> +static u64 imx_rproc_get_boot_addr(struct rproc *rproc, const struct firmware *fw)
> +{
> + struct imx_rproc *priv = rproc->priv;
> + const u8 *elf_data = (void *)fw->data;
> + u8 class = fw_elf_get_class(fw);
> + u64 bootaddr = rproc_elf_get_boot_addr(rproc, fw);
> + const void *shdr;
> + void __iomem *va;
> + u64 sh_addr, offset;
> +
> + if (priv->dcfg->devtype == IMX_RPROC_IMX8M) {
> + /*
> + * i.MX8M Cortex-M requires [stack, pc] be put in address
> + * [0, 4], so the da address is 0, size is 8 words.
> + */
> + va = (__force void __iomem *)rproc_da_to_va(rproc, 0, 8, NULL);
> + shdr = rproc_elf_find_shdr(rproc, fw, ".interrupts");
> + if (!shdr || !va)
> + return bootaddr;
> + sh_addr = elf_shdr_get_sh_addr(class, shdr);
This isn't used - why is it still there?
> + offset = elf_shdr_get_sh_offset(class, shdr);
> +
> + /*
> + * Write stack, pc to TCML start address. The TCML region
> + * is marked with ATT_IOMEM, so use writel.
> + */
> + writel(*(u32 *)(elf_data + offset), va);
> + writel(*(u32 *)(elf_data + offset + 4), va + 4);
Here you are writing 2 words at address 0x0 and 2 words at address 0x4. Why are
you saying the size is 8 words in the comment above?
> + }
> +
> + return bootaddr;
> +}
> +
> static const struct rproc_ops imx_rproc_ops = {
> .prepare = imx_rproc_prepare,
> .attach = imx_rproc_attach,
> @@ -647,7 +682,7 @@ static const struct rproc_ops imx_rproc_ops = {
> .find_loaded_rsc_table = rproc_elf_find_loaded_rsc_table,
> .get_loaded_rsc_table = imx_rproc_get_loaded_rsc_table,
> .sanity_check = rproc_elf_sanity_check,
> - .get_boot_addr = rproc_elf_get_boot_addr,
> + .get_boot_addr = imx_rproc_get_boot_addr,
> };
>
> static int imx_rproc_addr_init(struct imx_rproc *priv,
> --
> 2.37.1
>
