[U-Boot] [PATCH v2 7/7] MIPS: bootm: Add support for Vcore III linux kernel
Daniel Schwierzeck
daniel.schwierzeck at gmail.com
Sun Oct 28 17:54:02 UTC 2018
Hi Gregory,
sorry for the late response.
Am 09.10.18 um 13:58 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.
I'm still not convinced whether this patch is necessary. As far as I
understand, you can boot a mainline kernel with the device-tree blob way
or with the legacy way. The latter makes sense when booting a mainline
kernel with Redboot. But what's the use case for booting a mainline
kernel in mainline U-Boot in the legacy way? Do you still want to boot
out-of-tree legacy kernels with mainline U-Boot?
Apart from this is this single cmdline string specific to Redboot or
only to Microsemi? The former would be acceptable for a generic patch to
emulate a Redboot interface (similar to the YAMON one). But this should
be configurable for the user via Kconfig. You could enable this by
default with an "imply MIPS_BOOT_CMDLINE_REDBOOT" in your SoC/board
specific Kconfig part.
>
> 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.
Who exactly needs "root=/dev/ram0"? Normally the generic MIPS setup code
only needs "rd_start" and "rd_size" from cmdline respectively
"linux,initrd-start" and "linux,initrd-end" from the device-tree blob.
>
> Signed-off-by: Gregory CLEMENT <gregory.clement at bootlin.com>
> ---
> arch/mips/lib/bootm.c | 77 ++++++++++++++++++++++++++++++++-----------
> 1 file changed, 57 insertions(+), 20 deletions(-)
>
> diff --git a/arch/mips/lib/bootm.c b/arch/mips/lib/bootm.c
> index deca5189e3..803d5e1de3 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 +49,46 @@ 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:
> + /* fallthrough */
> + 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++;
> + case LEGACY_BOOT_YAML:
> + /* fallthrough */
> + 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 +102,11 @@ 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 +132,7 @@ 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 +141,8 @@ 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 +150,7 @@ 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 +158,13 @@ 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);
> + }
> }
> }
>
> @@ -276,11 +309,15 @@ 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();
> + } 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
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