On 2017/1/13 2:29, Sudeep Holla wrote:
> The cache hierarchy can be identified through Cache Level ID(CLIDR)
> architected system register. However in some cases it will provide
> only the number of cache levels that are integrated into the processor
> itself. In other words, it can't provide any information about the
> caches that are external and/or transparent.
>
> Some platforms require to export the information about all such external
> caches to the userspace applications via the sysfs interface.
>
> This patch adds support to override the cache levels using device tree
> to take such external non-architected caches into account.
>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
Tested-by: Tan Xiaojun <tanxiaojun@xxxxxxxxxx>
> ---
> arch/arm64/kernel/cacheinfo.c | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/cacheinfo.c b/arch/arm64/kernel/cacheinfo.c
> index 9617301f76b5..3f2250fc391b 100644
> --- a/arch/arm64/kernel/cacheinfo.c
> +++ b/arch/arm64/kernel/cacheinfo.c
> @@ -84,7 +84,7 @@ static void ci_leaf_init(struct cacheinfo *this_leaf,
>
> static int __init_cache_level(unsigned int cpu)
> {
> - unsigned int ctype, level, leaves;
> + unsigned int ctype, level, leaves, of_level;
> struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
>
> for (level = 1, leaves = 0; level <= MAX_CACHE_LEVEL; level++) {
> @@ -97,6 +97,17 @@ static int __init_cache_level(unsigned int cpu)
> leaves += (ctype == CACHE_TYPE_SEPARATE) ? 2 : 1;
> }
>
> + of_level = of_find_last_cache_level(cpu);
> + if (level < of_level) {
> + /*
> + * some external caches not specified in CLIDR_EL1
> + * the information may be available in the device tree
> + * only unified external caches are considered here
> + */
> + leaves += (of_level - level);
> + level = of_level;
> + }
> +
> this_cpu_ci->num_levels = level;
> this_cpu_ci->num_leaves = leaves;
> return 0;
> --
> 2.7.4
>
>
> .
>
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