[PATCH v3 0/7] Raspberry Pi miniuart support

[PATCH v3 0/7] Raspberry Pi miniuart support

[Rouven Czerwinski]

This patch series adds support for the raspberry pi miniuart (also called
aux-uart) to barebox.
With this series the miniuart overlay is no longer necessary to start barebox on
Raspberry Pi 3.

v3:
- Fix Indentation
  from Oleksij Rempel and Sascha Hauer

v2:
- Move console clock initialization into board core
- Retrieve the core clock frequency for the miniuart from the firmware
- Double the clock frequency in the ns16550 rpi init function instead of
  during initialization
  from Lucas Stach

Rouven Czerwinski (7):
  ARM: rpi: move clks into board specific rpi-common
  ARM: rpi: retrieve miniuart clock from firmware
  serial_ns16550: handle default reg-io-width
  serial_ns16550: add raspberry pi compatible and init
  ARM: rpi: add NS16550 support
  ARM: rpi: choose miniuart as stdout
  doc: bcm283x: remove miniuart overlay instruction

 Documentation/boards/bcm2835.rst          |  1 +-
 arch/arm/boards/raspberry-pi/rpi-common.c | 26 +++++++++-
 arch/arm/configs/rpi_defconfig            |  1 +-
 arch/arm/dts/bcm2837-rpi-3.dts            |  7 +--
 arch/arm/mach-bcm283x/core.c              | 19 +------
 drivers/serial/serial_ns16550.c           | 71 ++++++++++++++++--------
 6 files changed, 76 insertions(+), 49 deletions(-)

base-commit: 4d94b3c0208fedf9c9c2eed0053e9dffb9d52506
-- 
git-series 0.9.1

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[PATCH v3 1/7] ARM: rpi: move clks into board specific rpi-common

[Rouven Czerwinski]

We don't know if the firmware running on the raspberry pi is the same firmware
which is running on all bcm283x devices.
Therefore move the console clock initialization into the rpi-common.c board file.
A future commit will use this function to retrieve the miniuart clock from the
raspberry pi firmware.
No functional changes.

Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
---
 arch/arm/boards/raspberry-pi/rpi-common.c | 19 +++++++++++++++++++
 arch/arm/mach-bcm283x/core.c              | 19 -------------------
 2 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/arch/arm/boards/raspberry-pi/rpi-common.c b/arch/arm/boards/raspberry-pi/rpi-common.c
index 9f0531f..490aeef 100644
--- a/arch/arm/boards/raspberry-pi/rpi-common.c
+++ b/arch/arm/boards/raspberry-pi/rpi-common.c
@@ -297,6 +297,25 @@ static int rpi_clock_init(void)
 }
 postconsole_initcall(rpi_clock_init);
 
+static int rpi_console_clock_init(void)
+{
+	struct clk *clk;
+
+	clk = clk_fixed("apb_pclk", 0);
+	clk_register_clkdev(clk, "apb_pclk", NULL);
+
+	clk = clk_fixed("uart0-pl0110", 3 * 1000 * 1000);
+	clk_register_clkdev(clk, NULL, "uart0-pl0110");
+	clkdev_add_physbase(clk, 0x20201000, NULL);
+	clkdev_add_physbase(clk, 0x3f201000, NULL);
+
+	clk = clk_fixed("bcm2835-cs", 1 * 1000 * 1000);
+	clk_register_clkdev(clk, NULL, "bcm2835-cs");
+
+	return 0;
+}
+postcore_initcall(rpi_console_clock_init);
+
 static int rpi_env_init(void)
 {
 	struct stat s;
diff --git a/arch/arm/mach-bcm283x/core.c b/arch/arm/mach-bcm283x/core.c
index f1dcda8..f2528cf 100644
--- a/arch/arm/mach-bcm283x/core.c
+++ b/arch/arm/mach-bcm283x/core.c
@@ -31,25 +31,6 @@
 #include <mach/core.h>
 #include <linux/amba/bus.h>
 
-static int bcm2835_clk_init(void)
-{
-	struct clk *clk;
-
-	clk = clk_fixed("apb_pclk", 0);
-	clk_register_clkdev(clk, "apb_pclk", NULL);
-
-	clk = clk_fixed("uart0-pl0110", 3 * 1000 * 1000);
-	clk_register_clkdev(clk, NULL, "uart0-pl0110");
-	clkdev_add_physbase(clk, 0x20201000, NULL);
-	clkdev_add_physbase(clk, 0x3f201000, NULL);
-
-	clk = clk_fixed("bcm2835-cs", 1 * 1000 * 1000);
-	clk_register_clkdev(clk, NULL, "bcm2835-cs");
-
-	return 0;
-}
-postcore_initcall(bcm2835_clk_init);
-
 void bcm2835_add_device_sdram(u32 size)
 {
 	if (!size)
-- 
git-series 0.9.1

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[PATCH v3 2/7] ARM: rpi: retrieve miniuart clock from firmware

[Rouven Czerwinski]

The miniuart uses the core clock as the clock source. This clock is fixed by the
firmware to 250Mhz if enable_uart=1 is set in the config.txt file.
However a user could still choose to overclock the core frequency,
which would result in wrong baudrates computed by barebox.
Retrieve the core clock frequency from the firmware to allow all potential
firmware configurations to work with barebox.

Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
---
 arch/arm/boards/raspberry-pi/rpi-common.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm/boards/raspberry-pi/rpi-common.c b/arch/arm/boards/raspberry-pi/rpi-common.c
index 490aeef..e29177d 100644
--- a/arch/arm/boards/raspberry-pi/rpi-common.c
+++ b/arch/arm/boards/raspberry-pi/rpi-common.c
@@ -309,6 +309,13 @@ static int rpi_console_clock_init(void)
 	clkdev_add_physbase(clk, 0x20201000, NULL);
 	clkdev_add_physbase(clk, 0x3f201000, NULL);
 
+	clk = rpi_register_firmware_clock(BCM2835_MBOX_CLOCK_ID_CORE,
+					  "uart1-8250");
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	clkdev_add_physbase(clk, 0x3f215040, NULL);
+
 	clk = clk_fixed("bcm2835-cs", 1 * 1000 * 1000);
 	clk_register_clkdev(clk, NULL, "bcm2835-cs");
 
-- 
git-series 0.9.1

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[PATCH v3 3/7] serial_ns16550: handle default reg-io-width

[Rouven Czerwinski]

According to the device tree bindings for 8250, width is an optional property.
Default to 1 which is the same default value as used by the kernel.
Before this change the driver would not work for device trees which do not
include the optional binding.

Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
---
 drivers/serial/serial_ns16550.c | 46 +++++++++++++++++-----------------
 1 file changed, 23 insertions(+), 23 deletions(-)

diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
index 4d73ea8..8ddcfdb 100644
--- a/drivers/serial/serial_ns16550.c
+++ b/drivers/serial/serial_ns16550.c
@@ -297,36 +297,36 @@ static int ns16550_tstc(struct console_device *cdev)
 static void ns16550_probe_dt(struct device_d *dev, struct ns16550_priv *priv)
 {
 	struct device_node *np = dev->device_node;
-	u32 width;
+	u32 width = 1;
 
 	if (!IS_ENABLED(CONFIG_OFDEVICE))
 		return;
 
 	of_property_read_u32(np, "clock-frequency", &priv->plat.clock);
 	of_property_read_u32(np, "reg-shift", &priv->plat.shift);
-	if (!of_property_read_u32(np, "reg-io-width", &width))
-		switch (width) {
-		case 1:
-			priv->read_reg = ns16550_read_reg_mmio_8;
-			priv->write_reg = ns16550_write_reg_mmio_8;
-			break;
-		case 2:
-			priv->read_reg = ns16550_read_reg_mmio_16;
-			priv->write_reg = ns16550_write_reg_mmio_16;
-			break;
-		case 4:
-			if (of_device_is_big_endian(np)) {
-				priv->read_reg = ns16550_read_reg_mmio_32be;
-				priv->write_reg = ns16550_write_reg_mmio_32be;
-			} else {
-				priv->read_reg = ns16550_read_reg_mmio_32;
-				priv->write_reg = ns16550_write_reg_mmio_32;
-			}
-			break;
-		default:
-			dev_err(dev, "unsupported reg-io-width (%d)\n",
-				width);
+	of_property_read_u32(np, "reg-io-width", &width);
+	switch (width) {
+	case 1:
+		priv->read_reg = ns16550_read_reg_mmio_8;
+		priv->write_reg = ns16550_write_reg_mmio_8;
+		break;
+	case 2:
+		priv->read_reg = ns16550_read_reg_mmio_16;
+		priv->write_reg = ns16550_write_reg_mmio_16;
+		break;
+	case 4:
+		if (of_device_is_big_endian(np)) {
+			priv->read_reg = ns16550_read_reg_mmio_32be;
+			priv->write_reg = ns16550_write_reg_mmio_32be;
+		} else {
+			priv->read_reg = ns16550_read_reg_mmio_32;
+			priv->write_reg = ns16550_write_reg_mmio_32;
 		}
+		break;
+	default:
+		dev_err(dev, "unsupported reg-io-width (%d)\n",
+			width);
+	}
 }
 
 static struct ns16550_drvdata ns16450_drvdata = {
-- 
git-series 0.9.1

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[PATCH v3 4/7] serial_ns16550: add raspberry pi compatible and init

[Rouven Czerwinski]

Add the compatible for the Raspberry Pi AUX UART and an init function which
enables it via the aux register and configures the correct shift value.

Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
---
 drivers/serial/serial_ns16550.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
index 8ddcfdb..34b83f4 100644
--- a/drivers/serial/serial_ns16550.c
+++ b/drivers/serial/serial_ns16550.c
@@ -253,6 +253,20 @@ static void ns16550_jz_init_port(struct console_device *cdev)
 	ns16550_serial_init_port(cdev);
 }
 
+static void rpi_init_port(struct console_device *cdev)
+{
+	struct ns16550_priv *priv = to_ns16550_priv(cdev);
+
+	writeb(0x01, 0x3f215004);
+	priv->plat.shift = 2;
+	/*
+	 * We double the clock rate since the 16550 will divide by 16
+	 * (instead of 8 required by the BCM2835 peripheral manual)
+	 */
+	priv->plat.clock = priv->plat.clock*2;
+	ns16550_serial_init_port(cdev);
+}
+
 /*********** Exposed Functions **********************************/
 
 /**
@@ -353,6 +367,11 @@ static __maybe_unused struct ns16550_drvdata tegra_drvdata = {
 	.linux_console_name = "ttyS",
 };
 
+static struct ns16550_drvdata rpi_drvdata = {
+	.init_port = rpi_init_port,
+	.linux_console_name = "ttyS",
+};
+
 static int ns16550_init_iomem(struct device_d *dev, struct ns16550_priv *priv)
 {
 	struct resource *iores;
@@ -528,6 +547,12 @@ static struct of_device_id ns16550_serial_dt_ids[] = {
 		.data = &jz_drvdata,
 	},
 #endif
+#if IS_ENABLED(CONFIG_MACH_RPI_COMMON)
+	{
+	  .compatible = "brcm,bcm2835-aux-uart",
+	  .data = &rpi_drvdata,
+	},
+#endif
 	{
 		/* sentinel */
 	},
-- 
git-series 0.9.1

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Re: [PATCH v3 4/7] serial_ns16550: add raspberry pi compatible and init

[Rouven Czerwinski]

Rouven Czerwinski <r.czerwinski@pengutronix.de> writes:

> Add the compatible for the Raspberry Pi AUX UART and an init function which
> enables it via the aux register and configures the correct shift value.
>
> Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
> ---
>  drivers/serial/serial_ns16550.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
>
> diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
> index 8ddcfdb..34b83f4 100644
> --- a/drivers/serial/serial_ns16550.c
> +++ b/drivers/serial/serial_ns16550.c
> @@ -253,6 +253,20 @@ static void ns16550_jz_init_port(struct console_device *cdev)
>  	ns16550_serial_init_port(cdev);
>  }
>  
> +static void rpi_init_port(struct console_device *cdev)
> +{
> +	struct ns16550_priv *priv = to_ns16550_priv(cdev);
> +
> +	writeb(0x01, 0x3f215004);
> +	priv->plat.shift = 2;
> +	/*
> +	 * We double the clock rate since the 16550 will divide by 16
> +	 * (instead of 8 required by the BCM2835 peripheral manual)
> +	 */
> +	priv->plat.clock = priv->plat.clock*2;
> +	ns16550_serial_init_port(cdev);
> +}
> +
>  /*********** Exposed Functions **********************************/
>  
>  /**
> @@ -353,6 +367,11 @@ static __maybe_unused struct ns16550_drvdata tegra_drvdata = {
>  	.linux_console_name = "ttyS",
>  };
>  
> +static struct ns16550_drvdata rpi_drvdata = {
__maybe unused missing here.

> +	.init_port = rpi_init_port,
> +	.linux_console_name = "ttyS",
> +};
> +
>  static int ns16550_init_iomem(struct device_d *dev, struct ns16550_priv *priv)
>  {
>  	struct resource *iores;
> @@ -528,6 +547,12 @@ static struct of_device_id ns16550_serial_dt_ids[] = {
>  		.data = &jz_drvdata,
>  	},
>  #endif
> +#if IS_ENABLED(CONFIG_MACH_RPI_COMMON)
> +	{
> +	  .compatible = "brcm,bcm2835-aux-uart",
> +	  .data = &rpi_drvdata,
The indentation is still wrong.

Will send a v4.
> +	},
> +#endif
>  	{
>  		/* sentinel */
>  	},


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[PATCH v3 5/7] ARM: rpi: add NS16550 support

[Rouven Czerwinski]

Since the 16550 driver now supports the RPI3 miniuart, enable it in the default
config.

Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
---
 arch/arm/configs/rpi_defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/configs/rpi_defconfig b/arch/arm/configs/rpi_defconfig
index 2bb6158..dc5ab1f 100644
--- a/arch/arm/configs/rpi_defconfig
+++ b/arch/arm/configs/rpi_defconfig
@@ -63,6 +63,7 @@ CONFIG_CMD_OF_PROPERTY=y
 CONFIG_CMD_OFTREE=y
 CONFIG_CMD_TIME=y
 CONFIG_SERIAL_AMBA_PL011=y
+CONFIG_DRIVER_SERIAL_NS16550=y
 CONFIG_MCI=y
 CONFIG_MCI_BCM283X=y
 CONFIG_LED=y
-- 
git-series 0.9.1

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[PATCH v3 6/7] ARM: rpi: choose miniuart as stdout

[Rouven Czerwinski]

Since we now support the miniuart, enable it as the default stdout port.
With this change the device tree overlay to switch the miniuart to bluetooth is
no longer necessary.

Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
---
 arch/arm/dts/bcm2837-rpi-3.dts | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/arm/dts/bcm2837-rpi-3.dts b/arch/arm/dts/bcm2837-rpi-3.dts
index d6ffc36..194b41c 100644
--- a/arch/arm/dts/bcm2837-rpi-3.dts
+++ b/arch/arm/dts/bcm2837-rpi-3.dts
@@ -2,15 +2,10 @@
 
 / {
 	chosen {
-		stdout-path = &uart0;
+		stdout-path = &uart1;
 	};
 
 	memory {
 		reg = <0x0 0x0>;
 	};
 };
-
-&uart0 {
-	status = "okay";
-	/delete-node/ bluetooth;
-};
-- 
git-series 0.9.1

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[PATCH v3 7/7] doc: bcm283x: remove miniuart overlay instruction

[Rouven Czerwinski]

Since we now use the miniuart on the raspberry pi 3, the miniuart overlay is no
longer needed.

Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
---
 Documentation/boards/bcm2835.rst | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Documentation/boards/bcm2835.rst b/Documentation/boards/bcm2835.rst
index 79ea0ff..ea80d58 100644
--- a/Documentation/boards/bcm2835.rst
+++ b/Documentation/boards/bcm2835.rst
@@ -22,7 +22,6 @@ Raspberry Pi
 
          kernel=barebox.img
          enable_uart=1
-         dtoverlay=pi3-miniuart-bt
 
      (For more information, refer to the `documentation for config.txt`_.)
 
-- 
git-series 0.9.1

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