Re: [PATCH 6/8] ARM: nxp-imx8mq-evk: Replace trampoline

[Rouven Czerwinski <r.czerwinski@pengutronix.de>]

On Thu, 2019-08-22 at 14:51 +0200, Sascha Hauer wrote:
> When the TF-A finishes it jumps to a hardcoded address in DRAM. We
> used
> to put a trampoline there which brings us back to our image in SRAM.
> Instead of putting a trampoline into DRAM just copy the image there
> which simplifies things a bit.
> 
> Note that currently imx8_esdhc_load_piggy() uses that very same
> address
> as a temporary buffer. This is changed in the next patch. Currently
> the
> board is broken anyway, so we don't break bisectability.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  arch/arm/boards/nxp-imx8mq-evk/Makefile     |  2 +-
>  arch/arm/boards/nxp-imx8mq-evk/lowlevel.c   | 27 ++++---------------
> --
>  arch/arm/boards/nxp-imx8mq-evk/trampoline.S | 10 --------
>  3 files changed, 6 insertions(+), 33 deletions(-)
>  delete mode 100644 arch/arm/boards/nxp-imx8mq-evk/trampoline.S
> 
> diff --git a/arch/arm/boards/nxp-imx8mq-evk/Makefile
> b/arch/arm/boards/nxp-imx8mq-evk/Makefile
> index 7907de411f..2995f06f0f 100644
> --- a/arch/arm/boards/nxp-imx8mq-evk/Makefile
> +++ b/arch/arm/boards/nxp-imx8mq-evk/Makefile
> @@ -1,2 +1,2 @@
>  obj-y += board.o
> -lwl-y += lowlevel.o ddr_init.o ddrphy_train.o trampoline.o
> +lwl-y += lowlevel.o ddr_init.o ddrphy_train.o
> diff --git a/arch/arm/boards/nxp-imx8mq-evk/lowlevel.c
> b/arch/arm/boards/nxp-imx8mq-evk/lowlevel.c
> index cb1c499cb0..46dba16ec3 100644
> --- a/arch/arm/boards/nxp-imx8mq-evk/lowlevel.c
> +++ b/arch/arm/boards/nxp-imx8mq-evk/lowlevel.c
> @@ -56,27 +56,6 @@ static void nxp_imx8mq_evk_sram_setup(void)
>  	ddr_init();
>  }
>  
> -extern unsigned char trampoline_start[];
> -extern unsigned char trampoline_end[];
> -
> -static void nxp_imx8mq_evk_install_tfa_trampoline(void)
> -{
> -	unsigned int tramp_len;
> -	unsigned int offset;
> -	/*
> -	 * Create a trampoline which is places in DRAM and calls back
> into the
> -	 * PBL entry function found in the TCRAM. Register x0 is set to
> 1 to
> -	 * indicate that DRAM setup was already run.
> -	 */
> -	tramp_len = (void *)trampoline_end - (void *)trampoline_start;
> -	memcpy((void *)MX8MQ_ATF_BL33_BASE_ADDR, (void
> *)trampoline_start,
> -	       tramp_len);
> -
> -	offset = get_runtime_offset();
> -	memcpy((void *)MX8MQ_ATF_BL33_BASE_ADDR + tramp_len, &offset,
> -	       sizeof(offset));
> -}
> -
>  /*
>   * Power-on execution flow of start_nxp_imx8mq_evk() might not be
>   * obvious for a very first read, so here's, hopefully helpful,
> @@ -117,8 +96,12 @@ static __noreturn noinline void
> nxp_imx8mq_evk_start(void)
>  	 */
>  	if (current_el() == 3) {
>  		nxp_imx8mq_evk_sram_setup();
> -		nxp_imx8mq_evk_install_tfa_trampoline();
>  		get_builtin_firmware(imx8mq_bl31_bin, &bl31,
> &bl31_size);
> +		/*
> +		 * On completion the TF-A will jump to
> MX8MQ_ATF_BL33_BASE_ADDR in
> +		 * EL2. Copy ourselves there.
> +		 */
> +		memcpy((void *)MX8MQ_ATF_BL33_BASE_ADDR, _text,
> __bss_start - _text);
>  		imx8mq_atf_load_bl31(bl31, bl31_size);
>  	}
>  
> diff --git a/arch/arm/boards/nxp-imx8mq-evk/trampoline.S
> b/arch/arm/boards/nxp-imx8mq-evk/trampoline.S
> deleted file mode 100644
> index 54a1b76518..0000000000
> --- a/arch/arm/boards/nxp-imx8mq-evk/trampoline.S
> +++ /dev/null
> @@ -1,10 +0,0 @@
> -/* SPDX-License-Identifier: (GPL-2.0) */
> -#include <linux/linkage.h>
> -#include <asm/sections.h>
> -	.section .trampoline,"a"
> -	.globl  trampoline_start
> -trampoline_start:
> -	ldr	w19, trampoline_end
> -	br      x19
> -	.globl  trampoline_end
> -trampoline_end:

Reviewed-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>

- rcz


_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox