* Pratik Rajesh Sampat <psam...@linux.ibm.com> [2020-03-17 19:40:18]:
> 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 <psam...@linux.ibm.com>
> Reviewed-by: Ram Pai <linux...@us.ibm.com>
Reviewed-by: Vaidyanathan Srinivasan <sva...@linux.ibm.com>
>
> ---
> .../bindings/powerpc/opal/power-mgt.txt | 10 +++
> arch/powerpc/platforms/powernv/idle.c | 78 +++++++++++++++++++
> 2 files changed, 88 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/powerpc/opal/power-mgt.txt
> b/Documentation/devicetree/bindings/powerpc/opal/power-mgt.txt
> index 9d619e955576..093cb5fe3d2d 100644
> --- a/Documentation/devicetree/bindings/powerpc/opal/power-mgt.txt
> +++ b/Documentation/devicetree/bindings/powerpc/opal/power-mgt.txt
> @@ -116,3 +116,13 @@ otherwise. The length of all the property arrays must be
> the same.
> which of the fields of the PMICR are set in the corresponding
> entries in ibm,cpu-idle-state-pmicr. This is an optional
> property on POWER8 and is absent on POWER9.
> +
> +- self-restore:
> + Array of unsigned 64-bit values containing a property for sprn-mask
> + with each bit indicating the index of the supported SPR for the
> + functionality. This is an optional property for both Power8 and Power9
> +
> +- self-save:
> + Array of unsigned 64-bit values containing a property for sprn-mask
> + with each bit indicating the index of the supported SPR for the
> + functionality. This is an optional property for both Power8 and Power9
> diff --git a/arch/powerpc/platforms/powernv/idle.c
> b/arch/powerpc/platforms/powernv/idle.c
> index 97aeb45e897b..c39111b338ff 100644
> --- a/arch/powerpc/platforms/powernv/idle.c
> +++ b/arch/powerpc/platforms/powernv/idle.c
> @@ -1436,6 +1436,81 @@ 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;
> + u64 *temp_u64;
> + u64 bit_pos;
> +
> + nr_sprns = of_property_count_u64_elems(np, "sprn-bitmask");
> + if (nr_sprns <= 0)
> + return -EINVAL;
> + 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 = BIT_WORD(preferred_sprs[i].spr);
> + bit_pos = BIT_MASK(preferred_sprs[i].spr);
> + if ((temp_u64[bitmask_index] & 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 0;
> +}
> +
> +static int pnv_parse_deepstate_dt(void)
> +{
> + struct device_node *np;
> + int rc = 0, i;
> +
> + /* Self restore register population */
> + np = of_find_compatible_node(NULL, NULL, "ibm,opal-self-restore");
> + if (np) {
> + rc = extract_save_restore_state_dt(np, SELF_RESTORE_TYPE);
> + if (rc != 0)
> + return rc;
> + }
> + /* Self save register population */
> + np = of_find_compatible_node(NULL, NULL, "ibm,opal-self-save");
> + if (!np) {
> + for (i = 0; i < nr_preferred_sprs; i++)
> + preferred_sprs[i].supported_mode &= ~SELF_SAVE_STRICT;
> + } else {
> + rc = extract_save_restore_state_dt(np, SELF_SAVE_TYPE);
> + }
> + of_node_put(np);
> + return rc;
> +}
> +
> /*
> * This function parses device-tree and populates all the information
> * into pnv_idle_states structure. It also sets up nr_pnv_idle_states
> @@ -1584,6 +1659,9 @@ static int __init pnv_init_idle_states(void)
> return rc;
> pnv_probe_idle_states();
>
> + rc = pnv_parse_deepstate_dt();
> + if (rc)
> + return rc;
> if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
> if (!(supported_cpuidle_states & OPAL_PM_SLEEP_ENABLED_ER1)) {
> power7_fastsleep_workaround_entry = false;
> --
Thanks Michael for the detailed review and feedback. Your review
comments have been addressed by Pratik.
--Vaidy
