[U-Boot] [PATCH v3 7/7] MIPS: bootm: Add support for Vcore III linux kernel

[Daniel Schwierzeck <daniel.schwierzeck@gmail.com>]

Am 05.12.18 um 18:10 schrieb Gregory CLEMENT:
> The kernels built for the Vcore III linux kernel have different
> expectation in the way the data were passed.
> 
> Unlike with yamon, the command line is expected to be a single string
> passed in argv[1]. An other expectation is that the arguments are located
> in the cached address space.
> 
> However, like yamon, they expect that rd_start and rd_size was passed by
> the bootloader in the command line of the kernel, and besides that it
> also wait for the root=/dev/ram0.



> 
> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
> ---
>  arch/mips/lib/bootm.c | 78 ++++++++++++++++++++++++++++++++-----------
>  1 file changed, 58 insertions(+), 20 deletions(-)
> 
> diff --git a/arch/mips/lib/bootm.c b/arch/mips/lib/bootm.c
> index deca5189e3..a3831c28a4 100644
> --- a/arch/mips/lib/bootm.c
> +++ b/arch/mips/lib/bootm.c
> @@ -15,6 +15,11 @@ DECLARE_GLOBAL_DATA_PTR;
>  #define	LINUX_MAX_ENVS		256
>  #define	LINUX_MAX_ARGS		256
>  
> +enum legacy_boot_type {
> +	LEGACY_BOOT_YAML,
> +	LEGACY_BOOT_VCORE,
> +};
> +
>  static int linux_argc;
>  static char **linux_argv;
>  static char *linux_argp;
> @@ -44,22 +49,47 @@ void arch_lmb_reserve(struct lmb *lmb)
>  	lmb_reserve(lmb, sp, gd->ram_top - sp);
>  }
>  
> -static void linux_cmdline_init(void)
> +static void linux_cmdline_init(enum legacy_boot_type boot_type)
>  {
> +	switch (boot_type) {
> +		/*
> +		 * Vcore III linux kernels expect arguments in the cached
> +		 * address space. They also expect the command line being a
> +		 * single string in the first argument
> +		 */
> +	case LEGACY_BOOT_VCORE:
> +		linux_argv = (char **)(gd->bd->bi_boot_params);
> +		linux_argp = (char *)(linux_argv + LINUX_MAX_ARGS);
> +		linux_argv[1] = linux_argp;
> +		break;
> +	case LEGACY_BOOT_YAML:
> +		/* fall-through */
> +	default:
> +		linux_argv = (char **)UNCACHED_SDRAM(gd->bd->bi_boot_params);
> +		linux_argp = (char *)(linux_argv + LINUX_MAX_ARGS);
> +	}
>  	linux_argc = 1;
> -	linux_argv = (char **)UNCACHED_SDRAM(gd->bd->bi_boot_params);
>  	linux_argv[0] = 0;
> -	linux_argp = (char *)(linux_argv + LINUX_MAX_ARGS);
>  }
>  
> -static void linux_cmdline_set(const char *value, size_t len)
> +static void linux_cmdline_set(const char *value, size_t len,
> +			      enum legacy_boot_type boot_type)
>  {
> -	linux_argv[linux_argc] = linux_argp;
>  	memcpy(linux_argp, value, len);
> -	linux_argp[len] = 0;
> -
> +	switch (boot_type) {
> +	case LEGACY_BOOT_VCORE:
> +		linux_argv[linux_argc] = linux_argp;
> +		linux_argp[len] = 0;
> +		linux_argc++;
> +		break;
> +	case LEGACY_BOOT_YAML:
> +		/* fall-through */
> +	default:
> +		linux_argp[len] = ' ';
> +		linux_argp[len + 1] = 0;
> +		linux_argc = 2;
> +	}
>  	linux_argp += len + 1;
> -	linux_argc++;
>  }
>  
>  static void linux_cmdline_dump(void)
> @@ -73,12 +103,11 @@ static void linux_cmdline_dump(void)
>  		debug("   arg %03d: %s\n", i, linux_argv[i]);
>  }
>  
> -static void linux_cmdline_legacy(bootm_headers_t *images)
> +static void linux_cmdline_legacy(bootm_headers_t *images,
> +				 enum legacy_boot_type boot_type)
>  {
>  	const char *bootargs, *next, *quote;
> -
> -	linux_cmdline_init();
> -
> +	linux_cmdline_init(boot_type);
>  	bootargs = env_get("bootargs");
>  	if (!bootargs)
>  		return;
> @@ -104,7 +133,7 @@ static void linux_cmdline_legacy(bootm_headers_t *images)
>  		if (!next)
>  			next = bootargs + strlen(bootargs);
>  
> -		linux_cmdline_set(bootargs, next - bootargs);
> +		linux_cmdline_set(bootargs, next - bootargs, boot_type);
>  
>  		if (*next)
>  			next++;
> @@ -113,7 +142,8 @@ static void linux_cmdline_legacy(bootm_headers_t *images)
>  	}
>  }
>  
> -static void linux_cmdline_append(bootm_headers_t *images)
> +static void linux_cmdline_append(bootm_headers_t *images,
> +				 enum legacy_boot_type boot_type)
>  {
>  	char buf[24];
>  	ulong mem, rd_start, rd_size;
> @@ -121,7 +151,7 @@ static void linux_cmdline_append(bootm_headers_t *images)
>  	/* append mem */
>  	mem = gd->ram_size >> 20;
>  	sprintf(buf, "mem=%luM", mem);
> -	linux_cmdline_set(buf, strlen(buf));
> +	linux_cmdline_set(buf, strlen(buf), boot_type);
>  
>  	/* append rd_start and rd_size */
>  	rd_start = images->initrd_start;
> @@ -129,9 +159,13 @@ static void linux_cmdline_append(bootm_headers_t *images)
>  
>  	if (rd_size) {
>  		sprintf(buf, "rd_start=0x%08lX", rd_start);
> -		linux_cmdline_set(buf, strlen(buf));
> +		linux_cmdline_set(buf, strlen(buf), boot_type);
>  		sprintf(buf, "rd_size=0x%lX", rd_size);
> -		linux_cmdline_set(buf, strlen(buf));
> +		linux_cmdline_set(buf, strlen(buf), boot_type);
> +		if (boot_type ==  LEGACY_BOOT_VCORE) {
> +			sprintf(buf, "root=/dev/ram0");
> +			linux_cmdline_set(buf, strlen(buf), boot_type);
> +		}

if possible, add this via the bootargs environment variable from your
boot script

>  	}
>  }
>  
> @@ -276,11 +310,15 @@ static void boot_prep_linux(bootm_headers_t *images)
>  		boot_reloc_fdt(images);
>  		boot_setup_fdt(images);
>  	} else {
> -		if (CONFIG_IS_ENABLED(MIPS_BOOT_CMDLINE_LEGACY)) {
> -			linux_cmdline_legacy(images);
> +		if (CONFIG_IS_ENABLED(SOC_VCOREIII)) {
> +			linux_cmdline_legacy(images, LEGACY_BOOT_VCORE);
> +			linux_cmdline_append(images, LEGACY_BOOT_VCORE);
> +			linux_cmdline_dump();

as mentioned in the last review, please add this in a generic way. I
want to avoid SoC specific code in this file. You should add a Kconfig
symbol like CONFIG_MIPS_BOOT_CMDLINE_SINGLESTRING and imply this in your
SoC or board config. I think you could also use the U-Boot bootargs
buffer directly or make a copy for the kernel. There is no need to hack
the linux_cmdline_* functions.

> +		} else if (CONFIG_IS_ENABLED(MIPS_BOOT_CMDLINE_LEGACY)) {
> +			linux_cmdline_legacy(images, 0);
>  
>  			if (!CONFIG_IS_ENABLED(MIPS_BOOT_ENV_LEGACY))
> -				linux_cmdline_append(images);
> +				linux_cmdline_append(images, LEGACY_BOOT_YAML);
>  
>  			linux_cmdline_dump();
>  		}
> 

-- 
- Daniel