[v4,1/6] firmware/psci: Add definitions for PSCI v1.3 specification

From: David Woodhouse <dwmw@amazon.co.uk>

The v1.3 PSCI spec (https://developer.arm.com/documentation/den0022) adds
SYSTEM_OFF2, CLEAN_INV_MEMREGION and CLEAN_INV_MEMREGION_ATTRIBUTES
functions. Add definitions for them and their parameters, along with the
new TIMEOUT, RATE_LIMITED and BUSY error values.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 include/uapi/linux/psci.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

Hi David,

> On 24 Sep 2024, at 16:05, David Woodhouse <dwmw2@infradead.org> wrote:
> 
> From: David Woodhouse <dwmw@amazon.co.uk>
> 
> The v1.3 PSCI spec (https://developer.arm.com/documentation/den0022) adds
> SYSTEM_OFF2, CLEAN_INV_MEMREGION and CLEAN_INV_MEMREGION_ATTRIBUTES
> functions. Add definitions for them and their parameters, along with the
> new TIMEOUT, RATE_LIMITED and BUSY error values.
> 

DEN0022F REL superseded DEN0022F ALP1 which doesn’t describe CLEAN_INV_MEMREGION
or CLEAN_INV_MEMREGION_ATTRIBUTES. Defining those at another time shouldn’t be a
blocker for the rest of this patchset.

> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
> ---
> include/uapi/linux/psci.h | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
> 
> diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
> index 42a40ad3fb62..082ed689fdaf 100644
> --- a/include/uapi/linux/psci.h
> +++ b/include/uapi/linux/psci.h
> @@ -59,6 +59,8 @@
> #define PSCI_1_1_FN_SYSTEM_RESET2 PSCI_0_2_FN(18)
> #define PSCI_1_1_FN_MEM_PROTECT PSCI_0_2_FN(19)
> #define PSCI_1_1_FN_MEM_PROTECT_CHECK_RANGE PSCI_0_2_FN(20)
> +#define PSCI_1_3_FN_SYSTEM_OFF2 PSCI_0_2_FN(21)
> +#define PSCI_1_3_FN_CLEAN_INV_MEMREGION_ATTRIBUTES PSCI_0_2_FN(23)
> 
> #define PSCI_1_0_FN64_CPU_DEFAULT_SUSPEND PSCI_0_2_FN64(12)
> #define PSCI_1_0_FN64_NODE_HW_STATE PSCI_0_2_FN64(13)
> @@ -68,6 +70,8 @@
> 
> #define PSCI_1_1_FN64_SYSTEM_RESET2 PSCI_0_2_FN64(18)
> #define PSCI_1_1_FN64_MEM_PROTECT_CHECK_RANGE PSCI_0_2_FN64(20)
> +#define PSCI_1_3_FN64_SYSTEM_OFF2 PSCI_0_2_FN64(21)
> +#define PSCI_1_3_FN64_CLEAN_INV_MEMREGION PSCI_0_2_FN64(22)
> 
> /* PSCI v0.2 power state encoding for CPU_SUSPEND function */
> #define PSCI_0_2_POWER_STATE_ID_MASK 0xffff
> @@ -100,6 +104,19 @@
> #define PSCI_1_1_RESET_TYPE_SYSTEM_WARM_RESET 0
> #define PSCI_1_1_RESET_TYPE_VENDOR_START 0x80000000U
> 
> +/* PSCI v1.3 hibernate type for SYSTEM_OFF2 */
> +#define PSCI_1_3_HIBERNATE_TYPE_OFF 0

Should it be 1 as hibernate type?

> +
> +/* PSCI v1.3 flags for CLEAN_INV_MEMREGION */
> +#define PSCI_1_3_CLEAN_INV_MEMREGION_FLAG_DRY_RUN BIT(0)
> +
> +/* PSCI v1.3 attributes for CLEAN_INV_MEMREGION_ATTRIBUTES */
> +#define PSCI_1_3_CLEAN_INV_MEMREGION_ATTR_OP_TYPE 0
> +#define PSCI_1_3_CLEAN_INV_MEMREGION_ATTR_CPU_RDVZ 1
> +#define PSCI_1_3_CLEAN_INV_MEMREGION_ATTR_LATENCY 2
> +#define PSCI_1_3_CLEAN_INV_MEMREGION_ATTR_RATE_LIMIT 3
> +#define PSCI_1_3_CLEAN_INV_MEMREGION_ATTR_TIMEOUT 4
> +
> /* PSCI version decoding (independent of PSCI version) */
> #define PSCI_VERSION_MAJOR_SHIFT 16
> #define PSCI_VERSION_MINOR_MASK \
> @@ -133,5 +150,8 @@
> #define PSCI_RET_NOT_PRESENT -7
> #define PSCI_RET_DISABLED -8
> #define PSCI_RET_INVALID_ADDRESS -9
> +#define PSCI_RET_TIMEOUT -10
> +#define PSCI_RET_RATE_LIMITED -11
> +#define PSCI_RET_BUSY -12
> 

Thanks
Miguel

> #endif /* _UAPI_LINUX_PSCI_H */
> -- 
> 2.44.0
> 
>

On Thu, 2024-09-26 at 09:56 +0000, Miguel Luis wrote:
> 
> > +/* PSCI v1.3 hibernate type for SYSTEM_OFF2 */
> > +#define PSCI_1_3_HIBERNATE_TYPE_OFF 0
> 
> Should it be 1 as hibernate type?

It is in discovery, as BIT(PSCI_1_3_HIBERNATE_TYPE_OFF) == 1<<0 == 1.

But using a bitmask was only supposed to be for the discovery with
PSCI_FEATURES, as that has to advertise all the available hibernation
types.

The actual SYSTEM_OFF2 call was supposed to just take the numeric value
as an argument, since obviously *that* one isn't a bitmask. 

Except... I see that now the spec has finally been updated, it seems to
say that 0x1 is the value to pass to the SYSTEM_OFF2 call for
HIBERNATE_OFF, not 0x0. Which doesn't seem to make much sense, and I
don't recall it being what we discussed. Souvik, what happened there?

My understanding was that for each supported hibernation type #n, for
which HIBERERNATE_OFF is zero), the PSCI_FEATURES query would include
the bit (1<<n) to indicate that it is supported, and then the actual
SYSTEM_OFF2 call parameter would be (n) itself, precisely as
implemented here.

But the spec now seems to say that HIBERNATE_OFF is advertised as
(1<<0) in PSCI_FEATURES, but invoked with the value (1).

Is it too late to fix?

If it isn't just a thinko, what is the intent in the current spec?

If we have new hibernate types such that

 #define PSCI_1_3_HIBERNATE_TYPE_OFF 0
 #define PSCI_1_3_HIBERNATE_TYPE_FOO 1
 #define PSCI_1_3_HIBERNATE_TYPE_BAR 2

It seems obvious that the PSCI_FEATURES response will contain (1<<0),
(1<<1) and (1<<2) for them respectively, but what is supposed to be
passed to the actual SYSTEM_OFF2 call? Is it always just going to be
(PSCI_1_3_HIBERNATE_TYPE_xxx + 1)?

I think we should just fix §5.1.10 to report that 0x0 is HIBERNATE_OFF,
yes?