2019-10-19 08:05:57

by Jianxin Pan

[permalink] [raw]
Subject: [PATCH RESEND v3 0/4] arm64: meson: add support for A1 Power Domains

This patchset introduces a "Secure Power Doamin Controller". In A1/C1, power
controller registers such as PWRCTRL_FOCRSTN, PWRCTRL_PWR_OFF, PWRCTRL_MEM_PD
and PWRCTRL_ISO_EN, are in the secure domain, and should be accessed from ATF
by smc.


Changes since v1 at [1]:
- update domain id
- include dt-bindings in dts

Changes since v1 at [0]:
- use APIs from sm driver
- rename pwrc_secure_get_power as Kevin suggested
- add comments for always on domains
- replace arch_initcall_sync with builtin_platform_driver
- fix coding style

[0] https://lore.kernel.org/linux-amlogic/[email protected]
[1] https://lore.kernel.org/linux-amlogic/[email protected]

Jianxin Pan (4):
dt-bindings: power: add Amlogic secure power domains bindings
firmware: meson_sm: Add secure power domain support
soc: amlogic: Add support for Secure power domains controller
arm64: dts: meson: a1: add secure power domain controller

.../bindings/power/amlogic,meson-sec-pwrc.yaml | 42 +++++
arch/arm64/boot/dts/amlogic/meson-a1.dtsi | 8 +
drivers/firmware/meson/meson_sm.c | 2 +
drivers/soc/amlogic/Kconfig | 13 ++
drivers/soc/amlogic/Makefile | 1 +
drivers/soc/amlogic/meson-secure-pwrc.c | 204 +++++++++++++++++++++
include/dt-bindings/power/meson-a1-power.h | 32 ++++
include/linux/firmware/meson/meson_sm.h | 2 +
8 files changed, 304 insertions(+)
create mode 100644 Documentation/devicetree/bindings/power/amlogic,meson-sec-pwrc.yaml
create mode 100644 drivers/soc/amlogic/meson-secure-pwrc.c
create mode 100644 include/dt-bindings/power/meson-a1-power.h

--
2.7.4


2019-10-19 08:06:01

by Jianxin Pan

[permalink] [raw]
Subject: [PATCH v3 2/4] firmware: meson_sm: Add secure power domain support

The Amlogic Meson A1/C1 Secure Monitor implements calls to control power
domain.

Signed-off-by: Jianxin Pan <[email protected]>
---
drivers/firmware/meson/meson_sm.c | 2 ++
include/linux/firmware/meson/meson_sm.h | 2 ++
2 files changed, 4 insertions(+)

diff --git a/drivers/firmware/meson/meson_sm.c b/drivers/firmware/meson/meson_sm.c
index 1d5b4d7..7ec09f5 100644
--- a/drivers/firmware/meson/meson_sm.c
+++ b/drivers/firmware/meson/meson_sm.c
@@ -44,6 +44,8 @@ static const struct meson_sm_chip gxbb_chip = {
CMD(SM_EFUSE_WRITE, 0x82000031),
CMD(SM_EFUSE_USER_MAX, 0x82000033),
CMD(SM_GET_CHIP_ID, 0x82000044),
+ CMD(SM_PWRC_SET, 0x82000093),
+ CMD(SM_PWRC_GET, 0x82000095),
{ /* sentinel */ },
},
};
diff --git a/include/linux/firmware/meson/meson_sm.h b/include/linux/firmware/meson/meson_sm.h
index 6669e2a..4ed3989 100644
--- a/include/linux/firmware/meson/meson_sm.h
+++ b/include/linux/firmware/meson/meson_sm.h
@@ -12,6 +12,8 @@ enum {
SM_EFUSE_WRITE,
SM_EFUSE_USER_MAX,
SM_GET_CHIP_ID,
+ SM_PWRC_SET,
+ SM_PWRC_GET,
};

struct meson_sm_firmware;
--
2.7.4

2019-10-19 08:06:08

by Jianxin Pan

[permalink] [raw]
Subject: [PATCH v3 4/4] arm64: dts: meson: a1: add secure power domain controller

Enable power domain controller for Meson A1 SoC.

Signed-off-by: Jianxin Pan <[email protected]>
---
arch/arm64/boot/dts/amlogic/meson-a1.dtsi | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-a1.dtsi b/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
index 7210ad0..081bc31 100644
--- a/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
@@ -5,6 +5,7 @@

#include <dt-bindings/interrupt-controller/irq.h>
#include <dt-bindings/interrupt-controller/arm-gic.h>
+#include <dt-bindings/power/meson-a1-power.h>

/ {
compatible = "amlogic,a1";
@@ -93,6 +94,13 @@
clock-names = "xtal", "pclk", "baud";
status = "disabled";
};
+
+ pwrc: power-controller {
+ compatible = "amlogic,meson-a1-pwrc";
+ #power-domain-cells = <1>;
+ secure-monitor = <&sm>;
+ status = "okay";
+ };
};

gic: interrupt-controller@ff901000 {
--
2.7.4

2019-10-19 08:07:59

by Jianxin Pan

[permalink] [raw]
Subject: [PATCH v3 1/4] dt-bindings: power: add Amlogic secure power domains bindings

Add the bindings for the Amlogic Secure power domains, controlling the
secure power domains.

The bindings targets the Amlogic A1 and C1 compatible SoCs, in which the
power domain registers are in secure world.

Signed-off-by: Jianxin Pan <[email protected]>
---
.../bindings/power/amlogic,meson-sec-pwrc.yaml | 42 ++++++++++++++++++++++
include/dt-bindings/power/meson-a1-power.h | 32 +++++++++++++++++
2 files changed, 74 insertions(+)
create mode 100644 Documentation/devicetree/bindings/power/amlogic,meson-sec-pwrc.yaml
create mode 100644 include/dt-bindings/power/meson-a1-power.h

diff --git a/Documentation/devicetree/bindings/power/amlogic,meson-sec-pwrc.yaml b/Documentation/devicetree/bindings/power/amlogic,meson-sec-pwrc.yaml
new file mode 100644
index 00000000..88d8261
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/amlogic,meson-sec-pwrc.yaml
@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+# Copyright (c) 2019 Amlogic, Inc
+# Author: Jianxin Pan <[email protected]>
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/power/amlogic,meson-sec-pwrc.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Amlogic Meson Secure Power Domains
+
+maintainers:
+ - Jianxin Pan <[email protected]>
+
+description: |+
+ Meson Secure Power Domains used in A1/C1 SoCs.
+
+properties:
+ compatible:
+ enum:
+ - amlogic,meson-a1-pwrc
+
+ "#power-domain-cells":
+ const: 1
+
+ secure-monitor:
+ description: phandle to the secure-monitor node
+ $ref: /schemas/types.yaml#/definitions/phandle
+
+required:
+ - compatible
+ - "#power-domain-cells"
+ - secure-monitor
+
+examples:
+ - |
+ pwrc: power-controller {
+ compatible = "amlogic,meson-a1-pwrc";
+ #power-domain-cells = <1>;
+ secure-monitor = <&sm>;
+ };
+
+
diff --git a/include/dt-bindings/power/meson-a1-power.h b/include/dt-bindings/power/meson-a1-power.h
new file mode 100644
index 00000000..6cf50bf
--- /dev/null
+++ b/include/dt-bindings/power/meson-a1-power.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: (GPL-2.0+ or MIT) */
+/*
+ * Copyright (c) 2019 Amlogic, Inc.
+ * Author: Jianxin Pan <[email protected]>
+ */
+
+#ifndef _DT_BINDINGS_MESON_A1_POWER_H
+#define _DT_BINDINGS_MESON_A1_POWER_H
+
+#define PWRC_DSPA_ID 8
+#define PWRC_DSPB_ID 9
+#define PWRC_UART_ID 10
+#define PWRC_DMC_ID 11
+#define PWRC_I2C_ID 12
+#define PWRC_PSRAM_ID 13
+#define PWRC_ACODEC_ID 14
+#define PWRC_AUDIO_ID 15
+#define PWRC_OTP_ID 16
+#define PWRC_DMA_ID 17
+#define PWRC_SD_EMMC_ID 18
+#define PWRC_RAMA_ID 19
+#define PWRC_RAMB_ID 20
+#define PWRC_IR_ID 21
+#define PWRC_SPICC_ID 22
+#define PWRC_SPIFC_ID 23
+#define PWRC_USB_ID 24
+#define PWRC_NIC_ID 25
+#define PWRC_PDMIN_ID 26
+#define PWRC_RSA_ID 27
+#define PWRC_MAX_ID 28
+
+#endif
--
2.7.4

2019-10-19 08:08:10

by Jianxin Pan

[permalink] [raw]
Subject: [PATCH v3 3/4] soc: amlogic: Add support for Secure power domains controller

Add support for the Amlogic Secure Power controller. In A1/C1 series, power
control registers are in secure domain, and should be accessed by smc.

Signed-off-by: Jianxin Pan <[email protected]>
---
drivers/soc/amlogic/Kconfig | 13 ++
drivers/soc/amlogic/Makefile | 1 +
drivers/soc/amlogic/meson-secure-pwrc.c | 204 ++++++++++++++++++++++++++++++++
3 files changed, 218 insertions(+)
create mode 100644 drivers/soc/amlogic/meson-secure-pwrc.c

diff --git a/drivers/soc/amlogic/Kconfig b/drivers/soc/amlogic/Kconfig
index bc2c912..6cb06e7 100644
--- a/drivers/soc/amlogic/Kconfig
+++ b/drivers/soc/amlogic/Kconfig
@@ -48,6 +48,19 @@ config MESON_EE_PM_DOMAINS
Say yes to expose Amlogic Meson Everything-Else Power Domains as
Generic Power Domains.

+config MESON_SECURE_PM_DOMAINS
+ bool "Amlogic Meson Secure Power Domains driver"
+ depends on ARCH_MESON || COMPILE_TEST
+ depends on PM && OF
+ depends on HAVE_ARM_SMCCC
+ default ARCH_MESON
+ select PM_GENERIC_DOMAINS
+ select PM_GENERIC_DOMAINS_OF
+ help
+ Support for the power controller on Amlogic A1/C1 series.
+ Say yes to expose Amlogic Meson Secure Power Domains as Generic
+ Power Domains.
+
config MESON_MX_SOCINFO
bool "Amlogic Meson MX SoC Information driver"
depends on ARCH_MESON || COMPILE_TEST
diff --git a/drivers/soc/amlogic/Makefile b/drivers/soc/amlogic/Makefile
index de79d044..7b8c5d3 100644
--- a/drivers/soc/amlogic/Makefile
+++ b/drivers/soc/amlogic/Makefile
@@ -5,3 +5,4 @@ obj-$(CONFIG_MESON_GX_SOCINFO) += meson-gx-socinfo.o
obj-$(CONFIG_MESON_GX_PM_DOMAINS) += meson-gx-pwrc-vpu.o
obj-$(CONFIG_MESON_MX_SOCINFO) += meson-mx-socinfo.o
obj-$(CONFIG_MESON_EE_PM_DOMAINS) += meson-ee-pwrc.o
+obj-$(CONFIG_MESON_SECURE_PM_DOMAINS) += meson-secure-pwrc.o
diff --git a/drivers/soc/amlogic/meson-secure-pwrc.c b/drivers/soc/amlogic/meson-secure-pwrc.c
new file mode 100644
index 00000000..181b066
--- /dev/null
+++ b/drivers/soc/amlogic/meson-secure-pwrc.c
@@ -0,0 +1,204 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright (c) 2019 Amlogic, Inc.
+ * Author: Jianxin Pan <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/io.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <dt-bindings/power/meson-a1-power.h>
+#include <linux/arm-smccc.h>
+#include <linux/firmware/meson/meson_sm.h>
+
+#define PWRC_ON 1
+#define PWRC_OFF 0
+
+struct meson_secure_pwrc_domain {
+ struct generic_pm_domain base;
+ unsigned int index;
+ struct meson_secure_pwrc *pwrc;
+};
+
+struct meson_secure_pwrc {
+ struct meson_secure_pwrc_domain *domains;
+ struct genpd_onecell_data xlate;
+ struct meson_sm_firmware *fw;
+};
+
+struct meson_secure_pwrc_domain_desc {
+ unsigned int index;
+ unsigned int flags;
+ char *name;
+ bool (*is_off)(struct meson_secure_pwrc_domain *pwrc_domain);
+};
+
+struct meson_secure_pwrc_domain_data {
+ unsigned int count;
+ struct meson_secure_pwrc_domain_desc *domains;
+};
+
+static bool pwrc_secure_is_off(struct meson_secure_pwrc_domain *pwrc_domain)
+{
+ int sts = 1;
+
+ if (meson_sm_call(pwrc_domain->pwrc->fw, SM_PWRC_GET, &sts,
+ pwrc_domain->index, 0, 0, 0, 0) < 0)
+ pr_err("failed to get power domain status\n");
+
+ return !!sts;
+}
+
+static int meson_secure_pwrc_off(struct generic_pm_domain *domain)
+{
+ int sts = 0;
+ struct meson_secure_pwrc_domain *pwrc_domain =
+ container_of(domain, struct meson_secure_pwrc_domain, base);
+
+ if (meson_sm_call(pwrc_domain->pwrc->fw, SM_PWRC_SET, NULL,
+ pwrc_domain->index, PWRC_OFF, 0, 0, 0) < 0) {
+ pr_err("failed to set power domain off\n");
+ sts = -EINVAL;
+ }
+
+ return sts;
+}
+
+static int meson_secure_pwrc_on(struct generic_pm_domain *domain)
+{
+ int sts = 0;
+ struct meson_secure_pwrc_domain *pwrc_domain =
+ container_of(domain, struct meson_secure_pwrc_domain, base);
+
+ if (meson_sm_call(pwrc_domain->pwrc->fw, SM_PWRC_SET, NULL,
+ pwrc_domain->index, PWRC_ON, 0, 0, 0) < 0) {
+ pr_err("failed to set power domain on\n");
+ sts = -EINVAL;
+ }
+
+ return sts;
+}
+
+#define SEC_PD(__name, __flag) \
+[PWRC_##__name##_ID] = \
+{ \
+ .name = #__name, \
+ .index = PWRC_##__name##_ID, \
+ .is_off = pwrc_secure_is_off, \
+ .flags = __flag, \
+}
+
+static struct meson_secure_pwrc_domain_desc a1_pwrc_domains[] = {
+ SEC_PD(DSPA, 0),
+ SEC_PD(DSPB, 0),
+ /* UART should keep working in ATF after suspend and before resume */
+ SEC_PD(UART, GENPD_FLAG_ALWAYS_ON),
+ /* DMC is for DDR PHY ana/dig and DMC, and should be always on */
+ SEC_PD(DMC, GENPD_FLAG_ALWAYS_ON),
+ SEC_PD(I2C, 0),
+ SEC_PD(PSRAM, 0),
+ SEC_PD(ACODEC, 0),
+ SEC_PD(AUDIO, 0),
+ SEC_PD(OTP, 0),
+ SEC_PD(DMA, 0),
+ SEC_PD(SD_EMMC, 0),
+ SEC_PD(RAMA, 0),
+ /* SRAMB is used as AFT runtime memory, and should be always on */
+ SEC_PD(RAMB, GENPD_FLAG_ALWAYS_ON),
+ SEC_PD(IR, 0),
+ SEC_PD(SPICC, 0),
+ SEC_PD(SPIFC, 0),
+ SEC_PD(USB, 0),
+ /* NIC is for NIC400, and should be always on */
+ SEC_PD(NIC, GENPD_FLAG_ALWAYS_ON),
+ SEC_PD(PDMIN, 0),
+ SEC_PD(RSA, 0),
+};
+
+static int meson_secure_pwrc_probe(struct platform_device *pdev)
+{
+ int i;
+ struct device_node *sm_np;
+ struct meson_secure_pwrc *pwrc;
+ const struct meson_secure_pwrc_domain_data *match;
+
+ match = of_device_get_match_data(&pdev->dev);
+ if (!match) {
+ dev_err(&pdev->dev, "failed to get match data\n");
+ return -ENODEV;
+ }
+
+ sm_np = of_parse_phandle(pdev->dev.of_node, "secure-monitor", 0);
+ if (!sm_np) {
+ dev_err(&pdev->dev, "no secure-monitor node\n");
+ return -ENODEV;
+ }
+
+ pwrc = devm_kzalloc(&pdev->dev, sizeof(*pwrc), GFP_KERNEL);
+ if (!pwrc)
+ return -ENOMEM;
+
+ pwrc->fw = meson_sm_get(sm_np);
+ of_node_put(sm_np);
+ if (!pwrc->fw)
+ return -EPROBE_DEFER;
+
+ pwrc->xlate.domains = devm_kcalloc(&pdev->dev, match->count,
+ sizeof(*pwrc->xlate.domains),
+ GFP_KERNEL);
+ if (!pwrc->xlate.domains)
+ return -ENOMEM;
+
+ pwrc->domains = devm_kcalloc(&pdev->dev, match->count,
+ sizeof(*pwrc->domains), GFP_KERNEL);
+ if (!pwrc->domains)
+ return -ENOMEM;
+
+ pwrc->xlate.num_domains = match->count;
+ platform_set_drvdata(pdev, pwrc);
+
+ for (i = 0 ; i < match->count ; ++i) {
+ struct meson_secure_pwrc_domain *dom = &pwrc->domains[i];
+
+ if (!match->domains[i].index)
+ continue;
+
+ dom->pwrc = pwrc;
+ dom->index = match->domains[i].index;
+ dom->base.name = match->domains[i].name;
+ dom->base.flags = match->domains[i].flags;
+ dom->base.power_on = meson_secure_pwrc_on;
+ dom->base.power_off = meson_secure_pwrc_off;
+
+ pm_genpd_init(&dom->base, NULL, match->domains[i].is_off(dom));
+
+ pwrc->xlate.domains[i] = &dom->base;
+ }
+
+ return of_genpd_add_provider_onecell(pdev->dev.of_node, &pwrc->xlate);
+}
+
+static struct meson_secure_pwrc_domain_data meson_secure_a1_pwrc_data = {
+ .domains = a1_pwrc_domains,
+ .count = ARRAY_SIZE(a1_pwrc_domains),
+};
+
+static const struct of_device_id meson_secure_pwrc_match_table[] = {
+ {
+ .compatible = "amlogic,meson-a1-pwrc",
+ .data = &meson_secure_a1_pwrc_data,
+ },
+ { /* sentinel */ }
+};
+
+static struct platform_driver meson_secure_pwrc_driver = {
+ .probe = meson_secure_pwrc_probe,
+ .driver = {
+ .name = "meson_secure_pwrc",
+ .of_match_table = meson_secure_pwrc_match_table,
+ },
+};
+builtin_platform_driver(meson_secure_pwrc_driver);
--
2.7.4

2019-10-29 07:24:07

by Rob Herring (Arm)

[permalink] [raw]
Subject: Re: [PATCH v3 1/4] dt-bindings: power: add Amlogic secure power domains bindings

On Fri, Oct 18, 2019 at 05:32:44PM +0800, Jianxin Pan wrote:
> Add the bindings for the Amlogic Secure power domains, controlling the
> secure power domains.
>
> The bindings targets the Amlogic A1 and C1 compatible SoCs, in which the
> power domain registers are in secure world.
>
> Signed-off-by: Jianxin Pan <[email protected]>
> ---
> .../bindings/power/amlogic,meson-sec-pwrc.yaml | 42 ++++++++++++++++++++++
> include/dt-bindings/power/meson-a1-power.h | 32 +++++++++++++++++
> 2 files changed, 74 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/power/amlogic,meson-sec-pwrc.yaml
> create mode 100644 include/dt-bindings/power/meson-a1-power.h
>
> diff --git a/Documentation/devicetree/bindings/power/amlogic,meson-sec-pwrc.yaml b/Documentation/devicetree/bindings/power/amlogic,meson-sec-pwrc.yaml
> new file mode 100644
> index 00000000..88d8261
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/amlogic,meson-sec-pwrc.yaml
> @@ -0,0 +1,42 @@
> +# SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> +# Copyright (c) 2019 Amlogic, Inc
> +# Author: Jianxin Pan <[email protected]>
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/power/amlogic,meson-sec-pwrc.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Amlogic Meson Secure Power Domains
> +
> +maintainers:
> + - Jianxin Pan <[email protected]>
> +
> +description: |+
> + Meson Secure Power Domains used in A1/C1 SoCs.
> +
> +properties:
> + compatible:
> + enum:
> + - amlogic,meson-a1-pwrc
> +
> + "#power-domain-cells":
> + const: 1
> +
> + secure-monitor:
> + description: phandle to the secure-monitor node
> + $ref: /schemas/types.yaml#/definitions/phandle

Like the watchdog, make this a child or the secure firmware node. Or
just add '#power-domain-cells' to it. You don't really need a child node
here if there's not other resources in DT for this.

Rob

2019-10-29 12:12:46

by Jianxin Pan

[permalink] [raw]
Subject: Re: [PATCH v3 1/4] dt-bindings: power: add Amlogic secure power domains bindings

Hi Jerome,

Could you give some advice about this?

In a1/c1, watchdog and powerdomain are the same, they use secure monitor [0] and
there is no share memory needed.

[0]
https://lore.kernel.org/linux-amlogic/[email protected]/

On 2019/10/29 10:01, Rob Herring wrote:
> On Fri, Oct 18, 2019 at 05:32:44PM +0800, Jianxin Pan wrote:
>> Add the bindings for the Amlogic Secure power domains, controlling the
>> secure power domains.
>>
>> The bindings targets the Amlogic A1 and C1 compatible SoCs, in which the
>> power domain registers are in secure world.
>>
>> Signed-off-by: Jianxin Pan <[email protected]>
>> ---
>> .../bindings/power/amlogic,meson-sec-pwrc.yaml | 42 ++++++++++++++++++++++
>> include/dt-bindings/power/meson-a1-power.h | 32 +++++++++++++++++
>> 2 files changed, 74 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/power/amlogic,meson-sec-pwrc.yaml
>> create mode 100644 include/dt-bindings/power/meson-a1-power.h
>>
>> diff --git a/Documentation/devicetree/bindings/power/amlogic,meson-sec-pwrc.yaml b/Documentation/devicetree/bindings/power/amlogic,meson-sec-pwrc.yaml
>> new file mode 100644
>> index 00000000..88d8261
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/power/amlogic,meson-sec-pwrc.yaml
>> @@ -0,0 +1,42 @@
>> +# SPDX-License-Identifier: (GPL-2.0+ OR MIT)
>> +# Copyright (c) 2019 Amlogic, Inc
>> +# Author: Jianxin Pan <[email protected]>
>> +%YAML 1.2
>> +---
>> +$id: "http://devicetree.org/schemas/power/amlogic,meson-sec-pwrc.yaml#"
>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
>> +
>> +title: Amlogic Meson Secure Power Domains
>> +
>> +maintainers:
>> + - Jianxin Pan <[email protected]>
>> +
>> +description: |+
>> + Meson Secure Power Domains used in A1/C1 SoCs.
>> +
>> +properties:
>> + compatible:
>> + enum:
>> + - amlogic,meson-a1-pwrc
>> +
>> + "#power-domain-cells":
>> + const: 1
>> +
>> + secure-monitor:
>> + description: phandle to the secure-monitor node
>> + $ref: /schemas/types.yaml#/definitions/phandle
>
> Like the watchdog, make this a child or the secure firmware node. Or
> just add '#power-domain-cells' to it. You don't really need a child node
> here if there's not other resources in DT for this.
>
> Rob
>
> .
>