Re: [bootwrapper PATCH v2 07/13] Rework common init C code

[Andre Przywara <andre.przywara@arm.com>]

On Fri, 14 Jan 2022 10:56:47 +0000
Mark Rutland <mark.rutland@arm.com> wrote:

> In init_platform() we initialize a UART and announce the presence of the
> bootwrapper to the world. We do this relatively late in the boot-flow,
> and prior to this will silently ignore errors (e.g. in gic_secure_init).
> 
> To make it possible to provide improved diagnostics, and to allow us to
> move more initialization into C, this patch reworks the init code to
> call a C function earlier, where we can announce the presence of the
> boot-wrapper and perform other initialization.
> 
> In subsequent patches this will be expanded with more CPU
> initialization.
> 
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>

Reviewed-by: Andre Przywara <andre.przywara@arm.com>

Cheers,
Andre

> ---
>  Makefile.am         |  2 +-
>  arch/aarch32/boot.S |  5 +++++
>  arch/aarch64/boot.S |  4 ++++
>  common/boot.c       |  4 ----
>  common/init.c       | 24 ++++++++++++++++++++++++
>  common/platform.c   | 12 +++++++-----
>  include/platform.h  | 17 +++++++++++++++++
>  7 files changed, 58 insertions(+), 10 deletions(-)
>  create mode 100644 common/init.c
>  create mode 100644 include/platform.h
> 
> diff --git a/Makefile.am b/Makefile.am
> index f941b07..0651c38 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -34,7 +34,7 @@ endif
>  PSCI_CPU_OFF	:= 0x84000002
>  
>  COMMON_SRC	:= common/
> -COMMON_OBJ	:= boot.o bakery_lock.o platform.o lib.o
> +COMMON_OBJ	:= boot.o bakery_lock.o platform.o lib.o init.o
>  
>  ARCH_OBJ	:= boot.o stack.o utils.o
>  
> diff --git a/arch/aarch32/boot.S b/arch/aarch32/boot.S
> index 00c432d..ee073ea 100644
> --- a/arch/aarch32/boot.S
> +++ b/arch/aarch32/boot.S
> @@ -48,6 +48,9 @@ ASM_FUNC(_start)
>  	mov	r0, #1
>  	ldr	r1, =flag_no_el3
>  	str	r0, [r1]
> +
> +	bl	cpu_init_bootwrapper
> +
>  	b	start_no_el3
>  
>  _switch_monitor:
> @@ -71,6 +74,8 @@ _monitor:
>  	ldr	r0, =COUNTER_FREQ
>  	mcr	p15, 0, r0, c14, c0, 0		@ CNTFRQ
>  
> +	bl	cpu_init_bootwrapper
> +
>  	bl	gic_secure_init
>  
>  	/* Initialise boot method */
> diff --git a/arch/aarch64/boot.S b/arch/aarch64/boot.S
> index 45a0367..17b4a75 100644
> --- a/arch/aarch64/boot.S
> +++ b/arch/aarch64/boot.S
> @@ -141,6 +141,8 @@ reset_at_el3:
>  	b.eq	err_invalid_id
>  	bl	setup_stack
>  
> +	bl	cpu_init_bootwrapper
> +
>  	bl	gic_secure_init
>  
>  	b	start_el3
> @@ -181,6 +183,8 @@ reset_no_el3:
>  	ldr	x1, =flag_no_el3
>  	str	w0, [x1]
>  
> +	bl	cpu_init_bootwrapper
> +
>  	b	start_no_el3
>  
>  err_invalid_id:
> diff --git a/common/boot.c b/common/boot.c
> index c74d34c..29d53a4 100644
> --- a/common/boot.c
> +++ b/common/boot.c
> @@ -12,8 +12,6 @@
>  extern unsigned long entrypoint;
>  extern unsigned long dtb;
>  
> -void init_platform(void);
> -
>  void __noreturn jump_kernel(unsigned long address,
>  			    unsigned long a0,
>  			    unsigned long a1,
> @@ -62,8 +60,6 @@ void __noreturn first_spin(unsigned int cpu, unsigned long *mbox,
>  			   unsigned long invalid)
>  {
>  	if (cpu == 0) {
> -		init_platform();
> -
>  		*mbox = (unsigned long)&entrypoint;
>  		sevl();
>  		spin(mbox, invalid, 1);
> diff --git a/common/init.c b/common/init.c
> new file mode 100644
> index 0000000..9c471c9
> --- /dev/null
> +++ b/common/init.c
> @@ -0,0 +1,24 @@
> +/*
> + * init.c - common boot-wrapper initialization
> + *
> + * Copyright (C) 2021 ARM Limited. All rights reserved.
> + *
> + * Use of this source code is governed by a BSD-style license that can be
> + * found in the LICENSE.txt file.
> + */
> +#include <cpu.h>
> +#include <platform.h>
> +
> +static void announce_bootwrapper(void)
> +{
> +	print_string("Boot-wrapper v0.2\r\n\r\n");
> +}
> +
> +void cpu_init_bootwrapper(void)
> +{
> +	if (this_cpu_logical_id() == 0) {
> +		init_uart();
> +		announce_bootwrapper();
> +		init_platform();
> +	}
> +}
> diff --git a/common/platform.c b/common/platform.c
> index d11f568..47bf547 100644
> --- a/common/platform.c
> +++ b/common/platform.c
> @@ -1,5 +1,5 @@
>  /*
> - * platform.c - code to initialise everything required when first booting.
> + * platform.c - Platform initialization and I/O.
>   *
>   * Copyright (C) 2015 ARM Limited. All rights reserved.
>   *
> @@ -7,6 +7,7 @@
>   * found in the LICENSE.txt file.
>   */
>  
> +#include <cpu.h>
>  #include <stdint.h>
>  
>  #include <asm/io.h>
> @@ -30,7 +31,7 @@
>  #define V2M_SYS(reg)	((void *)SYSREGS_BASE + V2M_SYS_##reg)
>  #endif
>  
> -static void print_string(const char *str)
> +void print_string(const char *str)
>  {
>  	uint32_t flags;
>  
> @@ -47,7 +48,7 @@ static void print_string(const char *str)
>  	}
>  }
>  
> -void init_platform(void)
> +void init_uart(void)
>  {
>  	/*
>  	 * UART initialisation (38400 8N1)
> @@ -58,9 +59,10 @@ void init_platform(void)
>  	raw_writel(0x70,	PL011(UART_LCR_H));
>  	/* Enable the UART, TXen and RXen */
>  	raw_writel(0x301,	PL011(UARTCR));
> +}
>  
> -	print_string("Boot-wrapper v0.2\r\n\r\n");
> -
> +void init_platform(void)
> +{
>  #ifdef SYSREGS_BASE
>  	/*
>  	 * CLCD output site MB
> diff --git a/include/platform.h b/include/platform.h
> new file mode 100644
> index 0000000..e5248e1
> --- /dev/null
> +++ b/include/platform.h
> @@ -0,0 +1,17 @@
> +/*
> + * include/platform.h - Platform initialization and I/O.
> + *
> + * Copyright (C) 2021 ARM Limited. All rights reserved.
> + *
> + * Use of this source code is governed by a BSD-style license that can be
> + * found in the LICENSE.txt file.
> + */
> +#ifndef __PLATFORM_H
> +#define __PLATFORM_H
> +
> +void print_string(const char *str);
> +void init_uart(void);
> +
> +void init_platform(void);
> +
> +#endif /* __PLATFORM_H */


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