[PATCH v5 0/3] Adding the Sparx5 Switch Reset Driver

[PATCH v5 0/3] Adding the Sparx5 Switch Reset Driver

[Steen Hegelund]

This series provides the Microchip Sparx5 Switch Reset Driver

The Sparx5 Switch SoC has a number of components that can be reset
individually, but at least the Switch Core needs to be in a well defined
state at power on, when any of the Sparx5 drivers starts to access the
Switch Core, this reset driver is available.

The reset driver is loaded early via the postcore_initcall interface, and
will then be available for the other Sparx5 drivers (SGPIO, SwitchDev etc)
that are loaded next, and the first of them to be loaded can perform the
one-time Switch Core reset that is needed.

The driver has protection so that the system busses, DDR controller, PCI-E
and ARM A53 CPU and a few other subsystems are not touched by the reset.

The Sparx5 Chip Register Model can be browsed at this location:
https://github.com/microchip-ung/sparx-5_reginfo

History:

v4 -> v5 Changed the two syscons into IO ranges and updated the bindings to
         reflect this change.

v3 -> v4 Added commit message descriptions

v2 -> v3 Removed unused headers
         Renamed the reset controller dev member.
         Use regmap_read_poll_timeout instead of polling a function.
         Used two separate syscon entries in the binding
         Simplified the syscon error handling.
         Simplified the devm_reset_controller_register error handling.
         Moved the contents of the mchp_sparx5_reset_config function into
         the probe function.

v1 -> v2 Removed debug prints
         Changed the error handling to save the error code before jumping.

Steen Hegelund (3):
  dt-bindings: reset: microchip sparx5 reset driver bindings
  reset: mchp: sparx5: add switch reset driver
  arm64: dts: reset: add microchip sparx5 switch reset driver

 .../bindings/reset/microchip,rst.yaml         |  55 ++++++++
 arch/arm64/boot/dts/microchip/sparx5.dtsi     |   9 +-
 drivers/reset/Kconfig                         |   8 ++
 drivers/reset/Makefile                        |   1 +
 drivers/reset/reset-microchip-sparx5.c        | 130 ++++++++++++++++++
 5 files changed, 200 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/reset/microchip,rst.yaml
 create mode 100644 drivers/reset/reset-microchip-sparx5.c

-- 
2.30.0

[PATCH v5 1/3] dt-bindings: reset: microchip sparx5 reset driver bindings

[Steen Hegelund]

Document the Sparx5 reset device driver bindings

The driver uses two IO ranges on sparx5 for access to
the reset control and the reset status.

Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
---
 .../bindings/reset/microchip,rst.yaml         | 55 +++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/reset/microchip,rst.yaml

diff --git a/Documentation/devicetree/bindings/reset/microchip,rst.yaml b/Documentation/devicetree/bindings/reset/microchip,rst.yaml
new file mode 100644
index 000000000000..80046172c9f8
--- /dev/null
+++ b/Documentation/devicetree/bindings/reset/microchip,rst.yaml
@@ -0,0 +1,55 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/reset/microchip,rst.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Microchip Sparx5 Switch Reset Controller
+
+maintainers:
+  - Steen Hegelund <steen.hegelund@microchip.com>
+  - Lars Povlsen <lars.povlsen@microchip.com>
+
+description: |
+  The Microchip Sparx5 Switch provides reset control and implements the following
+  functions
+    - One Time Switch Core Reset (Soft Reset)
+
+properties:
+  $nodename:
+    pattern: "^reset-controller@[0-9a-f]+$"
+
+  compatible:
+    const: microchip,sparx5-switch-reset
+
+  reg:
+    items:
+      - description: cpu block registers
+      - description: global control block registers
+
+  reg-names:
+    items:
+      - const: cpu
+      - const: gcb
+
+  "#reset-cells":
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - "#reset-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    reset: reset-controller@0 {
+        compatible = "microchip,sparx5-switch-reset";
+        #reset-cells = <1>;
+        reg = <0x0 0xd0>,
+              <0x11010000 0x10000>;
+        reg-names = "cpu", "gcb";
+    };
+
-- 
2.30.0

Re: [PATCH v5 1/3] dt-bindings: reset: microchip sparx5 reset driver bindings

[Alexandre Belloni]

On 10/02/2021 10:19:50+0100, Steen Hegelund wrote:
> Document the Sparx5 reset device driver bindings
> 
> The driver uses two IO ranges on sparx5 for access to
> the reset control and the reset status.
> 
> Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
> ---
>  .../bindings/reset/microchip,rst.yaml         | 55 +++++++++++++++++++
>  1 file changed, 55 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/reset/microchip,rst.yaml
> 
> diff --git a/Documentation/devicetree/bindings/reset/microchip,rst.yaml b/Documentation/devicetree/bindings/reset/microchip,rst.yaml
> new file mode 100644
> index 000000000000..80046172c9f8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/reset/microchip,rst.yaml
> @@ -0,0 +1,55 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/reset/microchip,rst.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Microchip Sparx5 Switch Reset Controller
> +
> +maintainers:
> +  - Steen Hegelund <steen.hegelund@microchip.com>
> +  - Lars Povlsen <lars.povlsen@microchip.com>
> +
> +description: |
> +  The Microchip Sparx5 Switch provides reset control and implements the following
> +  functions
> +    - One Time Switch Core Reset (Soft Reset)
> +
> +properties:
> +  $nodename:
> +    pattern: "^reset-controller@[0-9a-f]+$"
> +
> +  compatible:
> +    const: microchip,sparx5-switch-reset
> +
> +  reg:
> +    items:
> +      - description: cpu block registers
> +      - description: global control block registers
> +
> +  reg-names:
> +    items:
> +      - const: cpu
> +      - const: gcb
> +

I still think this is not right because then you will be mapping the
same set of register using multiple drivers without any form of
synchronisation which will work because you are mapping the region
without requesting it. But this may lead to issues later.

At least, you should make cpu start at 0x80 and of size 4. Else, you
won't be able to define and use the GPRs that are in front of
CPU_REGS:RESET.

I would still keep DEVCPU_GCB:CHIP_REGS as a syscon, especially since
you are mapping the whole set of registers.


> +  "#reset-cells":
> +    const: 1
> +
> +required:
> +  - compatible
> +  - reg
> +  - reg-names
> +  - "#reset-cells"
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    reset: reset-controller@0 {
> +        compatible = "microchip,sparx5-switch-reset";
> +        #reset-cells = <1>;
> +        reg = <0x0 0xd0>,
> +              <0x11010000 0x10000>;
> +        reg-names = "cpu", "gcb";
> +    };
> +
> -- 
> 2.30.0
> 

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v5 1/3] dt-bindings: reset: microchip sparx5 reset driver bindings

[Steen Hegelund]

Hi Alex,

On Mon, 2021-02-15 at 18:32 +0100, Alexandre Belloni wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you
> know the content is safe
> 
> On 10/02/2021 10:19:50+0100, Steen Hegelund wrote:
> > Document the Sparx5 reset device driver bindings
> > 
> > The driver uses two IO ranges on sparx5 for access to
> > the reset control and the reset status.
> > 
> > Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
> > ---
> >  .../bindings/reset/microchip,rst.yaml         | 55
> > +++++++++++++++++++
> >  1 file changed, 55 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/reset/microchip,rst.yaml
> > 
> > diff --git
> > a/Documentation/devicetree/bindings/reset/microchip,rst.yaml
> > b/Documentation/devicetree/bindings/reset/microchip,rst.yaml
> > new file mode 100644
> > index 000000000000..80046172c9f8
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/reset/microchip,rst.yaml
> > @@ -0,0 +1,55 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: "http://devicetree.org/schemas/reset/microchip,rst.yaml#"
> > +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> > +
> > +title: Microchip Sparx5 Switch Reset Controller
> > +
> > +maintainers:
> > +  - Steen Hegelund <steen.hegelund@microchip.com>
> > +  - Lars Povlsen <lars.povlsen@microchip.com>
> > +
> > +description: |
> > +  The Microchip Sparx5 Switch provides reset control and
> > implements the following
> > +  functions
> > +    - One Time Switch Core Reset (Soft Reset)
> > +
> > +properties:
> > +  $nodename:
> > +    pattern: "^reset-controller@[0-9a-f]+$"
> > +
> > +  compatible:
> > +    const: microchip,sparx5-switch-reset
> > +
> > +  reg:
> > +    items:
> > +      - description: cpu block registers
> > +      - description: global control block registers
> > +
> > +  reg-names:
> > +    items:
> > +      - const: cpu
> > +      - const: gcb
> > +
> 
> I still think this is not right because then you will be mapping the
> same set of register using multiple drivers without any form of
> synchronisation which will work because you are mapping the region
> without requesting it. But this may lead to issues later.
> 
> At least, you should make cpu start at 0x80 and of size 4. Else, you
> won't be able to define and use the GPRs that are in front of
> CPU_REGS:RESET.
> 
> I would still keep DEVCPU_GCB:CHIP_REGS as a syscon, especially since
> you are mapping the whole set of registers.

Ok.  I will use a syscon for the General Control Block and a very small
range for the CPU Reset register, to minimize the register footprint.

> 
> 
> > +  "#reset-cells":
> > +    const: 1
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - reg-names
> > +  - "#reset-cells"
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    reset: reset-controller@0 {
> > +        compatible = "microchip,sparx5-switch-reset";
> > +        #reset-cells = <1>;
> > +        reg = <0x0 0xd0>,
> > +              <0x11010000 0x10000>;
> > +        reg-names = "cpu", "gcb";
> > +    };
> > +
> > --
> > 2.30.0
> > 
> 
> --
> Alexandre Belloni, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com


Thanks for your comments


-- 
BR
Steen

-=-=-=-=-=-=-=-=-=-=-=-=-=-=
steen.hegelund@microchip.com

[PATCH v5 2/3] reset: mchp: sparx5: add switch reset driver

[Steen Hegelund]

The Sparx5 Switch SoC has a number of components that can be reset
indiviually, but at least the Switch Core needs to be in a well defined
state at power on, when any of the Sparx5 drivers starts to access the
Switch Core, this reset driver is available.

The reset driver is loaded early via the postcore_initcall interface, and
will then be available for the other Sparx5 drivers (SGPIO, SwitchDev etc)
that are loaded next, and the first of them to be loaded can perform the
one-time Switch Core reset that is needed.

The driver has protection so that the system busses, DDR controller, PCI-E
and ARM A53 CPU and a few other subsystems are not touched by the reset.

Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
---
 drivers/reset/Kconfig                  |   8 ++
 drivers/reset/Makefile                 |   1 +
 drivers/reset/reset-microchip-sparx5.c | 130 +++++++++++++++++++++++++
 3 files changed, 139 insertions(+)
 create mode 100644 drivers/reset/reset-microchip-sparx5.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 71ab75a46491..05c240c47a8a 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -101,6 +101,14 @@ config RESET_LPC18XX
 	help
 	  This enables the reset controller driver for NXP LPC18xx/43xx SoCs.
 
+config RESET_MCHP_SPARX5
+	bool "Microchip Sparx5 reset driver"
+	depends on HAS_IOMEM || COMPILE_TEST
+	default y if SPARX5_SWITCH
+	select MFD_SYSCON
+	help
+	  This driver supports switch core reset for the Microchip Sparx5 SoC.
+
 config RESET_MESON
 	tristate "Meson Reset Driver"
 	depends on ARCH_MESON || COMPILE_TEST
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 1054123fd187..341fd9ab4bf6 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
 obj-$(CONFIG_RESET_INTEL_GW) += reset-intel-gw.o
 obj-$(CONFIG_RESET_LANTIQ) += reset-lantiq.o
 obj-$(CONFIG_RESET_LPC18XX) += reset-lpc18xx.o
+obj-$(CONFIG_RESET_MCHP_SPARX5) += reset-microchip-sparx5.o
 obj-$(CONFIG_RESET_MESON) += reset-meson.o
 obj-$(CONFIG_RESET_MESON_AUDIO_ARB) += reset-meson-audio-arb.o
 obj-$(CONFIG_RESET_NPCM) += reset-npcm.o
diff --git a/drivers/reset/reset-microchip-sparx5.c b/drivers/reset/reset-microchip-sparx5.c
new file mode 100644
index 000000000000..b243a12af085
--- /dev/null
+++ b/drivers/reset/reset-microchip-sparx5.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Microchip Sparx5 Switch Reset driver
+ *
+ * Copyright (c) 2020 Microchip Technology Inc. and its subsidiaries.
+ *
+ * The Sparx5 Chip Register Model can be browsed at this location:
+ * https://github.com/microchip-ung/sparx-5_reginfo
+ */
+#include <linux/mfd/syscon.h>
+#include <linux/of_device.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+
+#define PROTECT_REG    0x84
+#define PROTECT_BIT    BIT(10)
+#define SOFT_RESET_REG 0x08
+#define SOFT_RESET_BIT BIT(1)
+
+struct mchp_reset_context {
+	struct regmap *cpu_ctrl;
+	struct regmap *gcb_ctrl;
+	struct reset_controller_dev rcdev;
+};
+
+static struct regmap_config sparx5_reset_regmap_config = {
+	.reg_bits	= 32,
+	.val_bits	= 32,
+	.reg_stride	= 4,
+};
+
+static int sparx5_switch_reset(struct reset_controller_dev *rcdev,
+			       unsigned long id)
+{
+	struct mchp_reset_context *ctx =
+		container_of(rcdev, struct mchp_reset_context, rcdev);
+	u32 val;
+
+	/* Make sure the core is PROTECTED from reset */
+	regmap_update_bits(ctx->cpu_ctrl, PROTECT_REG, PROTECT_BIT, PROTECT_BIT);
+
+	/* Start soft reset */
+	regmap_write(ctx->gcb_ctrl, SOFT_RESET_REG, SOFT_RESET_BIT);
+
+	/* Wait for soft reset done */
+	return regmap_read_poll_timeout(ctx->gcb_ctrl, SOFT_RESET_REG, val,
+					(val & SOFT_RESET_BIT) == 0,
+					1, 100);
+}
+
+static const struct reset_control_ops sparx5_reset_ops = {
+	.reset = sparx5_switch_reset,
+};
+
+static int mchp_sparx5_map_io(struct platform_device *pdev, char *name,
+			      struct regmap **target)
+{
+	struct resource *res;
+	void __iomem *mem;
+	struct regmap *map;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
+	if (!res) {
+		dev_err(&pdev->dev, "No '%s' resource\n", name);
+		return -ENODEV;
+	}
+	mem = devm_ioremap(&pdev->dev, res->start, res->end - res->start + 1);
+	if (!mem) {
+		dev_err(&pdev->dev, "Could not map '%s' resource\n", name);
+		return -ENXIO;
+	}
+	sparx5_reset_regmap_config.name = res->name;
+	map = devm_regmap_init_mmio(&pdev->dev, mem, &sparx5_reset_regmap_config);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+	*target = map;
+	return 0;
+}
+
+static int mchp_sparx5_reset_probe(struct platform_device *pdev)
+{
+	struct device_node *dn = pdev->dev.of_node;
+	struct mchp_reset_context *ctx;
+	int err;
+
+	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	err = mchp_sparx5_map_io(pdev, "cpu", &ctx->cpu_ctrl);
+	if (err)
+		return err;
+	err = mchp_sparx5_map_io(pdev, "gcb", &ctx->gcb_ctrl);
+	if (err)
+		return err;
+
+	ctx->rcdev.owner = THIS_MODULE;
+	ctx->rcdev.nr_resets = 1;
+	ctx->rcdev.ops = &sparx5_reset_ops;
+	ctx->rcdev.of_node = dn;
+
+	return devm_reset_controller_register(&pdev->dev, &ctx->rcdev);
+}
+
+static const struct of_device_id mchp_sparx5_reset_of_match[] = {
+	{
+		.compatible = "microchip,sparx5-switch-reset",
+	},
+	{ /*sentinel*/ }
+};
+
+static struct platform_driver mchp_sparx5_reset_driver = {
+	.probe = mchp_sparx5_reset_probe,
+	.driver = {
+		.name = "sparx5-switch-reset",
+		.of_match_table = mchp_sparx5_reset_of_match,
+	},
+};
+
+static int __init mchp_sparx5_reset_init(void)
+{
+	return platform_driver_register(&mchp_sparx5_reset_driver);
+}
+
+postcore_initcall(mchp_sparx5_reset_init);
+
+MODULE_DESCRIPTION("Microchip Sparx5 switch reset driver");
+MODULE_AUTHOR("Steen Hegelund <steen.hegelund@microchip.com>");
+MODULE_LICENSE("Dual MIT/GPL");
-- 
2.30.0

[PATCH v5 3/3] arm64: dts: reset: add microchip sparx5 switch reset driver

[Steen Hegelund]

This provides reset driver support for the Microchip Sparx5 PCB134 and
PCB135 reference boards.

Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
---
 arch/arm64/boot/dts/microchip/sparx5.dtsi | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/boot/dts/microchip/sparx5.dtsi b/arch/arm64/boot/dts/microchip/sparx5.dtsi
index 380281f312d8..06ecaa9ac8aa 100644
--- a/arch/arm64/boot/dts/microchip/sparx5.dtsi
+++ b/arch/arm64/boot/dts/microchip/sparx5.dtsi
@@ -132,9 +132,12 @@ mux: mux-controller {
 			};
 		};
 
-		reset@611010008 {
-			compatible = "microchip,sparx5-chip-reset";
-			reg = <0x6 0x11010008 0x4>;
+		reset: reset-controller@0 {
+			compatible = "microchip,sparx5-switch-reset";
+			reg = <0x6 0x00000000 0xd0>,
+			      <0x6 0x11010000 0x10000>;
+			reg-names = "cpu", "gcb";
+			#reset-cells = <1>;
 		};
 
 		uart0: serial@600100000 {
-- 
2.30.0