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SubjectRe: [RESEND PATCH v2 3/3] powerpc/powernv: Parse device tree, population of SPR support
On Mon, Jan 13, 2020 at 09:15:09AM +0530, Pratik Rajesh Sampat wrote:
> Parse the device tree for nodes self-save, self-restore and populate
> support for the preferred SPRs based what was advertised by the device
> tree.
>
> Signed-off-by: Pratik Rajesh Sampat <psampat@linux.ibm.com>
> ---
> arch/powerpc/platforms/powernv/idle.c | 104 ++++++++++++++++++++++++++
> 1 file changed, 104 insertions(+)
>
> diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
> index d67d4d0b169b..e910ff40b7e6 100644
> --- a/arch/powerpc/platforms/powernv/idle.c
> +++ b/arch/powerpc/platforms/powernv/idle.c
> @@ -1429,6 +1429,107 @@ static void __init pnv_probe_idle_states(void)
> supported_cpuidle_states |= pnv_idle_states[i].flags;
> }
>
> +/*
> + * Extracts and populates the self save or restore capabilities
> + * passed from the device tree node
> + */
> +static int extract_save_restore_state_dt(struct device_node *np, int type)
> +{
> + int nr_sprns = 0, i, bitmask_index;
> + int rc = 0;
> + u64 *temp_u64;
> + const char *state_prop;
> + u64 bit_pos;
> +
> + state_prop = of_get_property(np, "status", NULL);
> + if (!state_prop) {
> + pr_warn("opal: failed to find the active value for self save/restore node");
> + return -EINVAL;
> + }
> + if (strncmp(state_prop, "disabled", 8) == 0) {
> + /*
> + * if the feature is not active, strip the preferred_sprs from
> + * that capability.
> + */
> + if (type == SELF_RESTORE_TYPE) {
> + for (i = 0; i < nr_preferred_sprs; i++) {
> + preferred_sprs[i].supported_mode &=
> + ~SELF_RESTORE_STRICT;
> + }
> + } else {
> + for (i = 0; i < nr_preferred_sprs; i++) {
> + preferred_sprs[i].supported_mode &=
> + ~SELF_SAVE_STRICT;
> + }
> + }
> + return 0;
> + }
> + nr_sprns = of_property_count_u64_elems(np, "sprn-bitmask");
> + if (nr_sprns <= 0)
> + return rc;
> + temp_u64 = kcalloc(nr_sprns, sizeof(u64), GFP_KERNEL);
> + if (of_property_read_u64_array(np, "sprn-bitmask",
> + temp_u64, nr_sprns)) {
> + pr_warn("cpuidle-powernv: failed to find registers in DT\n");
> + kfree(temp_u64);
> + return -EINVAL;
> + }
> + /*
> + * Populate acknowledgment of support for the sprs in the global vector
> + * gotten by the registers supplied by the firmware.
> + * The registers are in a bitmask, bit index within
> + * that specifies the SPR
> + */
> + for (i = 0; i < nr_preferred_sprs; i++) {
> + bitmask_index = preferred_sprs[i].spr / 64;
> + bit_pos = preferred_sprs[i].spr % 64;
> + if ((temp_u64[bitmask_index] & (1UL << bit_pos)) == 0) {
> + if (type == SELF_RESTORE_TYPE)
> + preferred_sprs[i].supported_mode &=
> + ~SELF_RESTORE_STRICT;
> + else
> + preferred_sprs[i].supported_mode &=
> + ~SELF_SAVE_STRICT;
> + continue;
> + }
> + if (type == SELF_RESTORE_TYPE) {
> + preferred_sprs[i].supported_mode |=
> + SELF_RESTORE_STRICT;
> + } else {
> + preferred_sprs[i].supported_mode |=
> + SELF_SAVE_STRICT;
> + }
> + }
> +
> + kfree(temp_u64);
> + return rc;
> +}
> +
> +static int pnv_parse_deepstate_dt(void)
> +{
> + struct device_node *np, *np1;
> + int rc = 0;
> +
> + /* Self restore register population */
> + np = of_find_node_by_path("/ibm,opal/power-mgt/self-restore");
> + if (!np) {
> + pr_warn("opal: self restore Node not found");
> + } else {
> + rc = extract_save_restore_state_dt(np, SELF_RESTORE_TYPE);
> + if (rc != 0)
> + return rc;
> + }
> + /* Self save register population */
> + np1 = of_find_node_by_path("/ibm,opal/power-mgt/self-save");

'np' can be reused? 'np1' is not needed.


Otherwise looks good.

Reviewed-by: Ram Pai <linuxram@us.ibm.com>

RP

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