The PSCI SYSTEM_RESET2 call allows vendor firmware to define additional
reset types which could be mapped to the reboot argument.
Setting up reboot on Qualcomm devices can be inconsistent from chipset
to chipset. Generally, there is a PMIC register that gets written to
decide the reboot type. There is also sometimes a cookie that can be
written to indicate that the bootloader should behave differently than a
regular boot. These knobs evolve over product generations and require
more drivers. Qualcomm firmwares are beginning to expose vendor
SYSTEM_RESET2 types to simplify driver requirements from Linux.
Add support in PSCI to statically wire reboot mode commands from
userspace to a vendor reset and cookie value using the device tree. The
DT bindings are similar to reboot mode framework except that 2
integers are accepted (the type and cookie). Also, reboot mode framework
is intended to program the cookies, but not actually reboot the host.
PSCI SYSTEM_RESET2 does both. I've not added support for reading ACPI
tables since I don't have any device which provides them + firmware that
supports vendor SYSTEM_RESET2 types.
Previous discussions around SYSTEM_RESET2:
- https://lore.kernel.org/lkml/[email protected]/T/
- https://lore.kernel.org/all/[email protected]/
Signed-off-by: Elliot Berman <[email protected]>
---
Changes in v4:
- Change mode- properties from uint32-matrix to uint32-array
- Restructure the reset-types node so only the restriction is in the
if/then schemas and not the entire definition
- Link to v3: https://lore.kernel.org/r/20240515-arm-psci-system_reset2-vendor-reboots-v3-0-16dd4f9c0ab4@quicinc.com
Changes in v3:
- Limit outer number of items to 1 for mode-* properties
- Move the reboot-mode for psci under a subnode "reset-types"
- Fix the DT node in qcm6490-idp so it doesn't overwrite the one from
sc7820.dtsi
- Link to v2: https://lore.kernel.org/r/20240414-arm-psci-system_reset2-vendor-reboots-v2-0-da9a055a648f@quicinc.com
Changes in v2:
- Fixes to schema as suggested by Rob and Krzysztof
- Add qcm6490 idp as first Qualcomm device to support
- Link to v1: https://lore.kernel.org/r/20231117-arm-psci-system_reset2-vendor-reboots-v1-0-03c4612153e2@quicinc.com
Changes in v1:
- Reference reboot-mode bindings as suggeted by Rob.
- Link to RFC: https://lore.kernel.org/r/20231030-arm-psci-system_reset2-vendor-reboots-v1-0-dcdd63352ad1@quicinc.com
---
Elliot Berman (4):
dt-bindings: power: reset: Convert mode-.* properties to array
dt-bindings: arm: Document reboot mode magic
firmware: psci: Read and use vendor reset types
arm64: dts: qcom: Add PSCI SYSTEM_RESET2 types for qcm6490-idp
Documentation/devicetree/bindings/arm/psci.yaml | 44 +++++++++++
.../bindings/power/reset/nvmem-reboot-mode.yaml | 5 ++
.../devicetree/bindings/power/reset/qcom,pon.yaml | 8 ++
.../bindings/power/reset/reboot-mode.yaml | 4 +-
.../bindings/power/reset/syscon-reboot-mode.yaml | 5 ++
arch/arm64/boot/dts/qcom/qcm6490-idp.dts | 7 ++
arch/arm64/boot/dts/qcom/sc7280.dtsi | 2 +-
drivers/firmware/psci/psci.c | 92 ++++++++++++++++++++++
8 files changed, 164 insertions(+), 3 deletions(-)
---
base-commit: e92bee9f861b466c676f0200be3e46af7bc4ac6b
change-id: 20231016-arm-psci-system_reset2-vendor-reboots-cc3ad456c070
Best regards,
--
Elliot Berman <[email protected]>
PSCI reboot mode will map a mode name to multiple magic values instead
of just one. Convert the mode-.* property to an array. Users of the
reboot-mode schema will need to specify the maxItems of the mode-.*
properties. Existing users will all be 1.
Signed-off-by: Elliot Berman <[email protected]>
---
.../devicetree/bindings/power/reset/nvmem-reboot-mode.yaml | 5 +++++
Documentation/devicetree/bindings/power/reset/qcom,pon.yaml | 8 ++++++++
Documentation/devicetree/bindings/power/reset/reboot-mode.yaml | 4 ++--
.../devicetree/bindings/power/reset/syscon-reboot-mode.yaml | 5 +++++
4 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml b/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml
index 627f8a6078c2..9b9bbc0f29e7 100644
--- a/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml
+++ b/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml
@@ -31,6 +31,11 @@ properties:
allOf:
- $ref: reboot-mode.yaml#
+patternProperties:
+ "^mode-.*$":
+ items:
+ maxItems: 1
+
required:
- compatible
- nvmem-cells
diff --git a/Documentation/devicetree/bindings/power/reset/qcom,pon.yaml b/Documentation/devicetree/bindings/power/reset/qcom,pon.yaml
index fc8105a7b9b2..4c87ff5ecc9a 100644
--- a/Documentation/devicetree/bindings/power/reset/qcom,pon.yaml
+++ b/Documentation/devicetree/bindings/power/reset/qcom,pon.yaml
@@ -54,6 +54,11 @@ required:
- compatible
- reg
+patternProperties:
+ "^mode-.*$":
+ items:
+ maxItems: 1
+
unevaluatedProperties: false
allOf:
@@ -75,6 +80,9 @@ allOf:
reg-names:
items:
- const: pon
+ else:
+ patternProperties:
+ "^mode-.*$": false
# Special case for pm8941, which doesn't store reset mode
- if:
diff --git a/Documentation/devicetree/bindings/power/reset/reboot-mode.yaml b/Documentation/devicetree/bindings/power/reset/reboot-mode.yaml
index ad0a0b95cec1..523602fb82d2 100644
--- a/Documentation/devicetree/bindings/power/reset/reboot-mode.yaml
+++ b/Documentation/devicetree/bindings/power/reset/reboot-mode.yaml
@@ -28,13 +28,13 @@ description: |
properties:
mode-normal:
- $ref: /schemas/types.yaml#/definitions/uint32
+ $ref: "#/patternProperties/^mode-.*$"
description:
Default value to set on a reboot if no command was provided.
patternProperties:
"^mode-.*$":
- $ref: /schemas/types.yaml#/definitions/uint32
+ $ref: /schemas/types.yaml#/definitions/uint32-array
additionalProperties: true
diff --git a/Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.yaml b/Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.yaml
index b6acff199cde..e9d2e3b27885 100644
--- a/Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.yaml
+++ b/Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.yaml
@@ -32,6 +32,11 @@ properties:
allOf:
- $ref: reboot-mode.yaml#
+patternProperties:
+ "^mode-.*$":
+ items:
+ maxItems: 1
+
unevaluatedProperties: false
required:
--
2.34.1
SoC vendors have different types of resets and are controlled through
various registers. For instance, Qualcomm chipsets can reboot to a
"download mode" that allows a RAM dump to be collected. Another example
is they also support writing a cookie that can be read by bootloader
during next boot. PSCI offers a mechanism, SYSTEM_RESET2, for these
vendor reset types to be implemented without requiring drivers for every
register/cookie.
Add support in PSCI to statically map reboot mode commands from
userspace to a vendor reset and cookie value using the device tree.
A separate initcall is needed to parse the devicetree, instead of using
psci_dt_init because mm isn't sufficiently set up to allocate memory.
Reboot mode framework is close but doesn't quite fit with the
design and requirements for PSCI SYSTEM_RESET2. Some of these issues can
be solved but doesn't seem reasonable in sum:
1. reboot mode registers against the reboot_notifier_list, which is too
early to call SYSTEM_RESET2. PSCI would need to remember the reset
type from the reboot-mode framework callback and use it
psci_sys_reset.
2. reboot mode assumes only one cookie/parameter is described in the
device tree. SYSTEM_RESET2 uses 2: one for the type and one for
cookie.
3. psci cpuidle driver already registers a driver against the
arm,psci-1.0 compatible. Refactoring would be needed to have both a
cpuidle and reboot-mode driver.
Tested-by: Florian Fainelli <[email protected]>
Signed-off-by: Elliot Berman <[email protected]>
---
drivers/firmware/psci/psci.c | 92 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 92 insertions(+)
diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
index d9629ff87861..e672b33b71d1 100644
--- a/drivers/firmware/psci/psci.c
+++ b/drivers/firmware/psci/psci.c
@@ -29,6 +29,8 @@
#include <asm/smp_plat.h>
#include <asm/suspend.h>
+#define REBOOT_PREFIX "mode-"
+
/*
* While a 64-bit OS can make calls with SMC32 calling conventions, for some
* calls it is necessary to use SMC64 to pass or return 64-bit values.
@@ -79,6 +81,14 @@ struct psci_0_1_function_ids get_psci_0_1_function_ids(void)
static u32 psci_cpu_suspend_feature;
static bool psci_system_reset2_supported;
+struct psci_reset_param {
+ const char *mode;
+ u32 reset_type;
+ u32 cookie;
+};
+static struct psci_reset_param *psci_reset_params;
+static size_t num_psci_reset_params;
+
static inline bool psci_has_ext_power_state(void)
{
return psci_cpu_suspend_feature &
@@ -305,9 +315,29 @@ static int get_set_conduit_method(const struct device_node *np)
return 0;
}
+static void psci_vendor_sys_reset2(unsigned long action, void *data)
+{
+ const char *cmd = data;
+ unsigned long ret;
+ size_t i;
+
+ for (i = 0; i < num_psci_reset_params; i++) {
+ if (!strcmp(psci_reset_params[i].mode, cmd)) {
+ ret = invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2),
+ psci_reset_params[i].reset_type,
+ psci_reset_params[i].cookie, 0);
+ pr_err("failed to perform reset \"%s\": %ld\n",
+ cmd, (long)ret);
+ }
+ }
+}
+
static int psci_sys_reset(struct notifier_block *nb, unsigned long action,
void *data)
{
+ if (data && num_psci_reset_params)
+ psci_vendor_sys_reset2(action, data);
+
if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) &&
psci_system_reset2_supported) {
/*
@@ -748,6 +778,68 @@ static const struct of_device_id psci_of_match[] __initconst = {
{},
};
+static int __init psci_init_system_reset2_modes(void)
+{
+ const size_t len = strlen(REBOOT_PREFIX);
+ struct psci_reset_param *param;
+ struct device_node *psci_np __free(device_node) = NULL;
+ struct device_node *np __free(device_node) = NULL;
+ struct property *prop;
+ size_t count = 0;
+ u32 magic[2];
+ int num;
+
+ if (!psci_system_reset2_supported)
+ return 0;
+
+ psci_np = of_find_matching_node(NULL, psci_of_match);
+ if (!psci_np)
+ return 0;
+
+ np = of_find_node_by_name(psci_np, "reset-types");
+ if (!np)
+ return 0;
+
+ for_each_property_of_node(np, prop) {
+ if (strncmp(prop->name, REBOOT_PREFIX, len))
+ continue;
+ num = of_property_count_elems_of_size(np, prop->name, sizeof(magic[0]));
+ if (num != 1 && num != 2)
+ continue;
+
+ count++;
+ }
+
+ param = psci_reset_params = kcalloc(count, sizeof(*psci_reset_params), GFP_KERNEL);
+ if (!psci_reset_params)
+ return -ENOMEM;
+
+ for_each_property_of_node(np, prop) {
+ if (strncmp(prop->name, REBOOT_PREFIX, len))
+ continue;
+
+ param->mode = kstrdup_const(prop->name + len, GFP_KERNEL);
+ if (!param->mode)
+ continue;
+
+ num = of_property_read_variable_u32_array(np, prop->name, magic, 1, 2);
+ if (num < 0) {
+ pr_warn("Failed to parse vendor reboot mode %s\n", param->mode);
+ kfree_const(param->mode);
+ continue;
+ }
+
+ /* Force reset type to be in vendor space */
+ param->reset_type = PSCI_1_1_RESET_TYPE_VENDOR_START | magic[0];
+ param->cookie = num == 2 ? magic[1] : 0;
+ param++;
+ num_psci_reset_params++;
+ }
+
+ return 0;
+}
+arch_initcall(psci_init_system_reset2_modes);
+
int __init psci_dt_init(void)
{
struct device_node *np;
--
2.34.1
Add bindings to describe vendor-specific reboot modes. Values here
correspond to valid parameters to vendor-specific reset types in PSCI
SYSTEM_RESET2 call.
Signed-off-by: Elliot Berman <[email protected]>
---
Documentation/devicetree/bindings/arm/psci.yaml | 44 +++++++++++++++++++++++++
1 file changed, 44 insertions(+)
diff --git a/Documentation/devicetree/bindings/arm/psci.yaml b/Documentation/devicetree/bindings/arm/psci.yaml
index cbb012e217ab..7bc828661dec 100644
--- a/Documentation/devicetree/bindings/arm/psci.yaml
+++ b/Documentation/devicetree/bindings/arm/psci.yaml
@@ -98,6 +98,28 @@ properties:
[1] Kernel documentation - ARM idle states bindings
Documentation/devicetree/bindings/cpu/idle-states.yaml
+ reset-types:
+ type: object
+ $ref: /schemas/power/reset/reboot-mode.yaml#
+ unevaluatedProperties: false
+ properties:
+ # "mode-normal" is just SYSTEM_RESET
+ mode-normal: false
+ patternProperties:
+ "^mode-.*$":
+ $ref: /schemas/types.yaml#/definitions/uint32-array
+ minItems: 1
+ maxItems: 2
+ description: |
+ Describes a vendor-specific reset type. The string after "mode-"
+ maps a reboot mode to the parameters in the PSCI SYSTEM_RESET2 call.
+
+ Parameters are named mode-xxx = <type[, cookie]>, where xxx
+ is the name of the magic reboot mode, type is the lower 31 bits
+ of the reset_type, and, optionally, the cookie value. If the cookie
+ is not provided, it is defaulted to zero.
+ The 31st bit (vendor-resets) will be implicitly set by the driver.
+
patternProperties:
"^power-domain-":
$ref: /schemas/power/power-domain.yaml#
@@ -137,6 +159,15 @@ allOf:
required:
- cpu_off
- cpu_on
+ - if:
+ not:
+ properties:
+ compatible:
+ contains:
+ const: arm,psci-1.0
+ then:
+ properties:
+ reset-types: false
additionalProperties: false
@@ -261,4 +292,17 @@ examples:
domain-idle-states = <&CLUSTER_RET>, <&CLUSTER_PWRDN>;
};
};
+
+ - |+
+
+ // Case 5: SYSTEM_RESET2 vendor resets
+ psci {
+ compatible = "arm,psci-1.0";
+ method = "smc";
+
+ reset-types {
+ mode-edl = <0>;
+ mode-bootloader = <1 2>;
+ };
+ };
...
--
2.34.1
On Tue, Jun 11, 2024 at 08:35:13AM -0700, Elliot Berman wrote:
> PSCI reboot mode will map a mode name to multiple magic values instead
> of just one. Convert the mode-.* property to an array. Users of the
> reboot-mode schema will need to specify the maxItems of the mode-.*
> properties. Existing users will all be 1.
>
> Signed-off-by: Elliot Berman <[email protected]>
> ---
> .../devicetree/bindings/power/reset/nvmem-reboot-mode.yaml | 5 +++++
> Documentation/devicetree/bindings/power/reset/qcom,pon.yaml | 8 ++++++++
> Documentation/devicetree/bindings/power/reset/reboot-mode.yaml | 4 ++--
> .../devicetree/bindings/power/reset/syscon-reboot-mode.yaml | 5 +++++
> 4 files changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml b/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml
> index 627f8a6078c2..9b9bbc0f29e7 100644
> --- a/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml
> +++ b/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml
> @@ -31,6 +31,11 @@ properties:
> allOf:
> - $ref: reboot-mode.yaml#
>
> +patternProperties:
> + "^mode-.*$":
> + items:
> + maxItems: 1
Drop 'items'. Otherwise, you are defining constraints of a matrix.
> +
> required:
> - compatible
> - nvmem-cells
> diff --git a/Documentation/devicetree/bindings/power/reset/qcom,pon.yaml b/Documentation/devicetree/bindings/power/reset/qcom,pon.yaml
> index fc8105a7b9b2..4c87ff5ecc9a 100644
> --- a/Documentation/devicetree/bindings/power/reset/qcom,pon.yaml
> +++ b/Documentation/devicetree/bindings/power/reset/qcom,pon.yaml
> @@ -54,6 +54,11 @@ required:
> - compatible
> - reg
>
> +patternProperties:
> + "^mode-.*$":
> + items:
> + maxItems: 1
> +
> unevaluatedProperties: false
>
> allOf:
> @@ -75,6 +80,9 @@ allOf:
> reg-names:
> items:
> - const: pon
> + else:
> + patternProperties:
> + "^mode-.*$": false
>
> # Special case for pm8941, which doesn't store reset mode
> - if:
> diff --git a/Documentation/devicetree/bindings/power/reset/reboot-mode.yaml b/Documentation/devicetree/bindings/power/reset/reboot-mode.yaml
> index ad0a0b95cec1..523602fb82d2 100644
> --- a/Documentation/devicetree/bindings/power/reset/reboot-mode.yaml
> +++ b/Documentation/devicetree/bindings/power/reset/reboot-mode.yaml
> @@ -28,13 +28,13 @@ description: |
>
> properties:
> mode-normal:
> - $ref: /schemas/types.yaml#/definitions/uint32
> + $ref: "#/patternProperties/^mode-.*$"
No need for this. The pattern schema will be applied already. Also, a
$ref to a regex is fragile as it won't work for some regex patterns.
> description:
> Default value to set on a reboot if no command was provided.
>
> patternProperties:
> "^mode-.*$":
> - $ref: /schemas/types.yaml#/definitions/uint32
> + $ref: /schemas/types.yaml#/definitions/uint32-array
>
> additionalProperties: true
>
> diff --git a/Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.yaml b/Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.yaml
> index b6acff199cde..e9d2e3b27885 100644
> --- a/Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.yaml
> +++ b/Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.yaml
> @@ -32,6 +32,11 @@ properties:
> allOf:
> - $ref: reboot-mode.yaml#
>
> +patternProperties:
> + "^mode-.*$":
> + items:
> + maxItems: 1
> +
> unevaluatedProperties: false
>
> required:
>
> --
> 2.34.1
>
On Tue, Jun 11, 2024 at 02:40:01PM -0600, Rob Herring wrote:
> On Tue, Jun 11, 2024 at 08:35:13AM -0700, Elliot Berman wrote:
> > PSCI reboot mode will map a mode name to multiple magic values instead
> > of just one. Convert the mode-.* property to an array. Users of the
> > reboot-mode schema will need to specify the maxItems of the mode-.*
> > properties. Existing users will all be 1.
> >
> > Signed-off-by: Elliot Berman <[email protected]>
> > ---
> > .../devicetree/bindings/power/reset/nvmem-reboot-mode.yaml | 5 +++++
> > Documentation/devicetree/bindings/power/reset/qcom,pon.yaml | 8 ++++++++
> > Documentation/devicetree/bindings/power/reset/reboot-mode.yaml | 4 ++--
> > .../devicetree/bindings/power/reset/syscon-reboot-mode.yaml | 5 +++++
> > 4 files changed, 20 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml b/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml
> > index 627f8a6078c2..9b9bbc0f29e7 100644
> > --- a/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml
> > +++ b/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml
> > @@ -31,6 +31,11 @@ properties:
> > allOf:
> > - $ref: reboot-mode.yaml#
> >
> > +patternProperties:
> > + "^mode-.*$":
> > + items:
> > + maxItems: 1
>
> Drop 'items'. Otherwise, you are defining constraints of a matrix.
>
If I do this, I also have to add $ref: .../uint32-array as well so
the property can be picked up as an array type. Let me know if this isn't
right, otherwise I'll send out a fixed version in a few days.
Thanks,
Elliot
On Tue, Jun 11, 2024 at 04:23:00PM -0700, Elliot Berman wrote:
> On Tue, Jun 11, 2024 at 02:40:01PM -0600, Rob Herring wrote:
> > On Tue, Jun 11, 2024 at 08:35:13AM -0700, Elliot Berman wrote:
> > > PSCI reboot mode will map a mode name to multiple magic values instead
> > > of just one. Convert the mode-.* property to an array. Users of the
> > > reboot-mode schema will need to specify the maxItems of the mode-.*
> > > properties. Existing users will all be 1.
> > >
> > > Signed-off-by: Elliot Berman <[email protected]>
> > > ---
> > > .../devicetree/bindings/power/reset/nvmem-reboot-mode.yaml | 5 +++++
> > > Documentation/devicetree/bindings/power/reset/qcom,pon.yaml | 8 ++++++++
> > > Documentation/devicetree/bindings/power/reset/reboot-mode.yaml | 4 ++--
> > > .../devicetree/bindings/power/reset/syscon-reboot-mode.yaml | 5 +++++
> > > 4 files changed, 20 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml b/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml
> > > index 627f8a6078c2..9b9bbc0f29e7 100644
> > > --- a/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml
> > > +++ b/Documentation/devicetree/bindings/power/reset/nvmem-reboot-mode.yaml
> > > @@ -31,6 +31,11 @@ properties:
> > > allOf:
> > > - $ref: reboot-mode.yaml#
> > >
> > > +patternProperties:
> > > + "^mode-.*$":
> > > + items:
> > > + maxItems: 1
> >
> > Drop 'items'. Otherwise, you are defining constraints of a matrix.
> >
>
> If I do this, I also have to add $ref: .../uint32-array as well so
> the property can be picked up as an array type. Let me know if this isn't
> right, otherwise I'll send out a fixed version in a few days.
Ah, I suppose the tools get confused with what to do here. That's an
issue I'm working on addressing. The issue is everything is a matrix
because without other information for a property we don't know how to
decode them. But with the schemas being fairly complete now and the move
away from DTB->YAML decoding, we can decode properties to the right
type. One issue to switch over is places where this 'everything is a
matrix' crept into schemas. I've been fixing these. The above is an
example of this.
So for now, just drop 'items'. It won't enforce anything, but once we
switch over it will.
Rob