[PATCH] ARM: nitrogen6: add lowlevel UART initialization

[PATCH] ARM: nitrogen6: add lowlevel UART initialization

[Rouven Czerwinski]

Mux UART1 and UART2 correctly to allow usage of DEBUG_LL.
This commit has only been tested on nitrogen6q.

Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
---
 .../boundarydevices-nitrogen6/lowlevel.c      | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/arch/arm/boards/boundarydevices-nitrogen6/lowlevel.c b/arch/arm/boards/boundarydevices-nitrogen6/lowlevel.c
index 74ff71fc24..47c231396d 100644
--- a/arch/arm/boards/boundarydevices-nitrogen6/lowlevel.c
+++ b/arch/arm/boards/boundarydevices-nitrogen6/lowlevel.c
@@ -1,16 +1,40 @@
 #include <common.h>
+#include <debug_ll.h>
 #include <mach/generic.h>
 #include <mach/esdctl.h>
 #include <asm/barebox-arm.h>
+#include <serial/imx-uart.h>
 
 extern char __dtb_imx6q_nitrogen6x_start[];
 
+static inline void setup_uart(void)
+{
+   void __iomem *iomuxbase = (void *)MX6_IOMUXC_BASE_ADDR;
+
+   //UART 1
+   writel(0x1, iomuxbase + 0x02a8);
+   writel(0x1, iomuxbase + 0x02ac);
+
+   //UART 2
+   writel(0x4, iomuxbase + 0x00bc);
+   writel(0x4, iomuxbase + 0x00c0);
+   writel(0x0, iomuxbase + 0x0928);
+
+   imx6_ungate_all_peripherals();
+   imx6_uart_setup((void *)MX6_UART2_BASE_ADDR);
+   pbl_set_putc(imx_uart_putc, (void *)MX6_UART2_BASE_ADDR);
+}
+
+
 ENTRY_FUNCTION(start_imx6q_nitrogen6x_1g, r0, r1, r2)
 {
 	void *fdt;
 
 	imx6_cpu_lowlevel_init();
 
+	if (IS_ENABLED(CONFIG_DEBUG_LL))
+		setup_uart();
+
 	fdt = __dtb_imx6q_nitrogen6x_start + get_runtime_offset();
 
 	imx6q_barebox_entry(fdt);
-- 
2.24.1


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Re: [PATCH] ARM: nitrogen6: add lowlevel UART initialization

[Ahmad Fatoum]

Hello Rouven,

On 1/2/20 11:23 AM, Rouven Czerwinski wrote:
> +static inline void setup_uart(void)
> +{
> +   void __iomem *iomuxbase = (void *)MX6_IOMUXC_BASE_ADDR;
> +
> +   //UART 1
> +   writel(0x1, iomuxbase + 0x02a8);
> +   writel(0x1, iomuxbase + 0x02ac);
> +
> +   //UART 2
> +   writel(0x4, iomuxbase + 0x00bc);
> +   writel(0x4, iomuxbase + 0x00c0);
> +   writel(0x0, iomuxbase + 0x0928);

There's imx_setup_pad that you can use along with symbolic names for
better readability.

> +   imx6_ungate_all_peripherals();
> +   imx6_uart_setup((void *)MX6_UART2_BASE_ADDR);

There's imx6_uart_setup_ll that passes in the address of CONFIG_DEBUG_IMX_UART_PORT.
Use that one instead.

> +   pbl_set_putc(imx_uart_putc, (void *)MX6_UART2_BASE_ADDR);

DEBUG_LL is a global setting. pbl_set_putc can be used to have PBL console
output for a board, even if DEBUG_LL is off or configured for another board.
Thus having pbl_set_putc guarded by a IS_ENABLED(CONFIG_DEBUG_LL) doesn't make
sense. pbl_set_putc can also only be called after relocation, which hasn't
happened yet.

Cheers
Ahmad


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Re: [PATCH] ARM: nitrogen6: add lowlevel UART initialization

[Lucas Stach]

On Do, 2020-01-02 at 11:23 +0100, Rouven Czerwinski wrote:
> Mux UART1 and UART2 correctly to allow usage of DEBUG_LL.

There is only one UART intended as console on this board. Why are you
setting up 2 UARTs here?

Regards,
Lucas

> This commit has only been tested on nitrogen6q.
> 
> Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
> ---
>  .../boundarydevices-nitrogen6/lowlevel.c      | 24
> +++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/arch/arm/boards/boundarydevices-nitrogen6/lowlevel.c
> b/arch/arm/boards/boundarydevices-nitrogen6/lowlevel.c
> index 74ff71fc24..47c231396d 100644
> --- a/arch/arm/boards/boundarydevices-nitrogen6/lowlevel.c
> +++ b/arch/arm/boards/boundarydevices-nitrogen6/lowlevel.c
> @@ -1,16 +1,40 @@
>  #include <common.h>
> +#include <debug_ll.h>
>  #include <mach/generic.h>
>  #include <mach/esdctl.h>
>  #include <asm/barebox-arm.h>
> +#include <serial/imx-uart.h>
>  
>  extern char __dtb_imx6q_nitrogen6x_start[];
>  
> +static inline void setup_uart(void)
> +{
> +   void __iomem *iomuxbase = (void *)MX6_IOMUXC_BASE_ADDR;
> +
> +   //UART 1
> +   writel(0x1, iomuxbase + 0x02a8);
> +   writel(0x1, iomuxbase + 0x02ac);
> +
> +   //UART 2
> +   writel(0x4, iomuxbase + 0x00bc);
> +   writel(0x4, iomuxbase + 0x00c0);
> +   writel(0x0, iomuxbase + 0x0928);
> +
> +   imx6_ungate_all_peripherals();
> +   imx6_uart_setup((void *)MX6_UART2_BASE_ADDR);
> +   pbl_set_putc(imx_uart_putc, (void *)MX6_UART2_BASE_ADDR);
> +}
> +
> +
>  ENTRY_FUNCTION(start_imx6q_nitrogen6x_1g, r0, r1, r2)
>  {
>  	void *fdt;
>  
>  	imx6_cpu_lowlevel_init();
>  
> +	if (IS_ENABLED(CONFIG_DEBUG_LL))
> +		setup_uart();
> +
>  	fdt = __dtb_imx6q_nitrogen6x_start + get_runtime_offset();
>  
>  	imx6q_barebox_entry(fdt);


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Re: [PATCH] ARM: nitrogen6: add lowlevel UART initialization

[Rouven Czerwinski]

On Mon, 2020-01-06 at 10:46 +0100, Lucas Stach wrote:
> On Do, 2020-01-02 at 11:23 +0100, Rouven Czerwinski wrote:
> > Mux UART1 and UART2 correctly to allow usage of DEBUG_LL.
> 
> There is only one UART intended as console on this board. Why are you
> setting up 2 UARTs here?

I am using this to work on OP-TEE, which does not implement the UART
initialization and instead relies on the bootloader. This way barebox
and OP-TEE don't need to share the same UART.
 
Regards,
Rouven


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