[U-Boot] [RFC] command/cache: Add flush_cache command

Albert ARIBAUD
2013-03-19T22:01:41Z

Hi York,

On Tue, 19 Mar 2013 13:29:52 -0700, York Sun <yorksun@freescale.com>
wrote:

> When we need the copied code/data in the main memory, we can flush the
> cache now. It uses the existing function flush_cache. Syntax is
>
> flush_cache <addr> <size>
>
> The addr and size are given in hexadecimal. Like memory command, there is
> no sanity check for the parameters.
>
> Signed-off-by: York Sun <yorksun@freescale.com>
> ---
> common/cmd_cache.c | 30 ++++++++++++++++++++++++++++++
> 1 file changed, 30 insertions(+)
>
> diff --git a/common/cmd_cache.c b/common/cmd_cache.c
> index 5512f92..93b7337 100644
> --- a/common/cmd_cache.c
> +++ b/common/cmd_cache.c
> @@ -94,6 +94,29 @@ int do_dcache(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
> return 0;
> }
>
> +void __weak flush_cache(ulong addr, ulong size)
> +{
> + puts("No arch specific flush_cache available!\n");
> + /* please define arch specific flush_cache */
> +}
> +
> +int do_flush_cache(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
> +{
> + ulong addr, size;
> +
> + switch (argc) {
> + case 3:
> + addr = simple_strtoul(argv[1], NULL, 16);
> + size = simple_strtoul(argv[2], NULL, 16);
> + flush_cache(addr, size);
> + break;
> + default:
> + return cmd_usage(cmdtp);
> + }
> + return 0;
> +
> +}
> +
> static int parse_argv(const char *s)
> {
> if (strcmp(s, "flush") == 0)
> @@ -120,3 +143,10 @@ U_BOOT_CMD(
> "[on, off, flush]\n"
> " - enable, disable, or flush data (writethrough) cache"
> );
> +
> +U_BOOT_CMD(
> + flush_cache, 3, 0, do_flush_cache,
> + "flush cache for a range",
> + "<addr> <size>\n"
> + " - flush cache for specificed range"
> +);

What's the point of this command exactly? I can see the point of range
flushes (and invalidates) in the code for drivers that use DMA, but as a
shell command, I fail to see the interest of it.

Amicalement,
--
Albert.