Re: [PATCH] bcm283x: debug_ll: add RaspberryPi 4 PL011 UART support

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 8/24/26 12:13 AM, chalianis1@gmail.com wrote:
> From: Chali Anis <chalianis1@gmail.com>
> 
> Add a DEBUG_RPI4_UART choice for low-level debugging on RaspberryPi 4
> and CM4 boards via the PL011 UART (uart0), for setups where the
> disable-bt overlay routes it onto the GPIO header pins instead of the
> mini UART. Mirrors the existing RPi1/RPi2-3 PL011 debug_ll support:
> firmware configures the UART, so debug_ll_init() is a no-op.
> 
> Assisted-by: Claude Sonnet 5
> Signed-off-by: Chali Anis <chalianis1@gmail.com>

Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

> ---
>  common/Kconfig.debug_ll         | 10 ++++++++++
>  include/mach/bcm283x/debug_ll.h | 10 ++++++++++
>  include/mach/bcm283x/platform.h |  1 +
>  3 files changed, 21 insertions(+)
> 
> diff --git a/common/Kconfig.debug_ll b/common/Kconfig.debug_ll
> index 8445b4be0872..5a28dc4a61e7 100644
> --- a/common/Kconfig.debug_ll
> +++ b/common/Kconfig.debug_ll
> @@ -275,6 +275,16 @@ config DEBUG_RPI2_3_UART
>  	  Say Y here if you want low-level debugging support on
>  	  RaspberryPi 2 and 3 boards.
>  
> +config DEBUG_RPI4_UART
> +	bool "RaspberryPi 4 PL011 UART"
> +	depends on ARCH_BCM283X
> +	select DEBUG_BCM283X_UART
> +	help
> +	  Say Y here if you want low-level debugging support on
> +	  RaspberryPi 4 / CM4 boards using the PL011 UART (uart0),
> +	  e.g. when the disable-bt overlay routes it onto the GPIO
> +	  header pins instead of the mini UART.
> +
>  config DEBUG_RPI3_MINI_UART
>  	bool "RaspberryPi 3 mini UART"
>  	depends on ARCH_BCM283X
> diff --git a/include/mach/bcm283x/debug_ll.h b/include/mach/bcm283x/debug_ll.h
> index a6a3b8f08856..3f2d5ddc9857 100644
> --- a/include/mach/bcm283x/debug_ll.h
> +++ b/include/mach/bcm283x/debug_ll.h
> @@ -40,6 +40,16 @@ static inline void debug_ll_init(void)
>  #define DEBUG_LL_UART_ADDR BCM2836_PL011_BASE
>  #include <debug_ll/pl011.h>
>  
> +#elif defined CONFIG_DEBUG_RPI4_UART
> +
> +static inline void debug_ll_init(void)
> +{
> +	/* Configured by ROM */
> +}
> +
> +#define DEBUG_LL_UART_ADDR BCM2711_PL011_BASE
> +#include <debug_ll/pl011.h>
> +
>  #elif defined CONFIG_DEBUG_RPI3_MINI_UART
>  
>  static inline uint8_t debug_ll_read_reg(void __iomem *base, int reg)
> diff --git a/include/mach/bcm283x/platform.h b/include/mach/bcm283x/platform.h
> index b957ac8de35e..54d8b38bd8ed 100644
> --- a/include/mach/bcm283x/platform.h
> +++ b/include/mach/bcm283x/platform.h
> @@ -32,6 +32,7 @@
>  
>  #define BCM2835_PL011_BASE 0x20201000
>  #define BCM2836_PL011_BASE 0x3f201000UL
> +#define BCM2711_PL011_BASE 0xfe201000UL
>  #define BCM2835_MINIUART_BASE 0x20215040
>  #define BCM2836_MINIUART_BASE 0x3f215040UL
>  #define BCM2711_MINIUART_BASE 0xfe215040UL
> 

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