Re: [PATCH 4/4] sunxi: move arch timer setup out of board/ directory

Samuel Holland
2022-12-14T06:15:03Z

Hi Andre,

On 12/13/22 18:22, Andre Przywara wrote:
> At the moment we have an #ifdef-protected routine in
> board/sunxi/board.c, which sets up the arch timer CNTFRQ register, if
> that hasn't been done already.
> This only applies to ARMv7 SoCs running in secure state, and so is
> much better located in the arch/arm/mach-sunxi directory.
>
> Move that routine into a separate function and file in said directory,
> which also allows to trigger the compilation for ARMv7 in the Makefile.
> Also move the call to it into the arch/arm version of board.c.
>
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
> arch/arm/mach-sunxi/Makefile | 4 ++++
> arch/arm/mach-sunxi/arch_timer.c | 39 ++++++++++++++++++++++++++++++++
> arch/arm/mach-sunxi/board.c | 14 ++++++++----
> board/sunxi/board.c | 34 +---------------------------
> 4 files changed, 54 insertions(+), 37 deletions(-)
> create mode 100644 arch/arm/mach-sunxi/arch_timer.c
>
> diff --git a/arch/arm/mach-sunxi/Makefile b/arch/arm/mach-sunxi/Makefile
> index 58f807cb82d..335c44476e9 100644
> --- a/arch/arm/mach-sunxi/Makefile
> +++ b/arch/arm/mach-sunxi/Makefile
> @@ -26,8 +26,12 @@ obj-$(CONFIG_MACH_SUN8I) += clock_sun6i.o
> endif
> obj-$(CONFIG_MACH_SUN9I) += clock_sun9i.o gtbus_sun9i.o
> obj-$(CONFIG_SUN50I_GEN_H6) += clock_sun50i_h6.o
> +
> ifndef CONFIG_ARM64
> obj-y += timer.o
> +ifndef CONFIG_MACH_SUNIV

Probably Allwinner will not release any new ARMv5 SoC, but would it be
more future-proof (and a bit more meaningful) to condition this on
CONFIG_CPU_V7A?

Alternatively, would it make sense to put this code inside
arch/arm/cpu/armv7/arch_timer.c? I don't know why we wouldn't want to
enable CONFIG_SYS_ARCH_TIMER on sunxi SoCs where it is available. And
making this generic could eventually remove the need for the version in
arch/arm/cpu/armv7/nonsec_virt.S. But this patch is still an improvement
as-is.

Tested-by: Samuel Holland <samuel@sholland.org>

> +obj-y += arch_timer.o
> +endif
> endif
>
> ifdef CONFIG_SPL_BUILD
> diff --git a/arch/arm/mach-sunxi/arch_timer.c b/arch/arm/mach-sunxi/arch_timer.c
> new file mode 100644
> index 00000000000..c0e4310741f
> --- /dev/null
> +++ b/arch/arm/mach-sunxi/arch_timer.c
> @@ -0,0 +1,39 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * ARM Generic Timer CNTFRQ setup
> + *
> + * (C) Copyright 2013 Oliver Schinagl <oliver@schinagl.nl>

`git blame` points to cba69eeeaa67d3fb93ec6f3abab1f653abf895a9 and
d96ebc468d0dff6eb6f069bba03b3f0e33aa22de as the source for this code, so
this authorship is incorrect.

> + */
> +
> +#include <stdint.h>

This does not do what you expect, or really anything at all. The comment
there suggests using linux/types.h.

Regards,
Samuel

> +#include <log.h>
> +#include <asm/armv7.h>
> +
> +void setup_arch_timer(void)
> +{
> + uint32_t id_pfr1, freq;
> +
> + asm volatile("mrc p15, 0, %0, c0, c1, 1" : "=r"(id_pfr1));
> + debug("id_pfr1: 0x%08x\n", id_pfr1);
> + /* Generic Timer Extension available? */
> + if (((id_pfr1 >> CPUID_ARM_GENTIMER_SHIFT) & 0xf) == 0)
> + return;
> +
> + /*
> + * CNTFRQ is a secure register, so we will crash if we try to
> + * write this from the non-secure world (read is OK, though).
> + * In case some bootcode has already set the correct value,
> + * we avoid the risk of writing to it.
> + */
> + asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r"(freq));
> + if (freq == CONFIG_COUNTER_FREQUENCY)
> + return;
> +
> + debug("arch timer frequency is %d Hz, should be %d, fixing ...\n",
> + freq, CONFIG_COUNTER_FREQUENCY);
> + if (IS_ENABLED(CONFIG_NON_SECURE))
> + printf("arch timer frequency is wrong, but cannot adjust it\n");
> + else
> + asm volatile("mcr p15, 0, %0, c14, c0, 0"
> + : : "r"(CONFIG_COUNTER_FREQUENCY));
> +}
> diff --git a/arch/arm/mach-sunxi/board.c b/arch/arm/mach-sunxi/board.c
> index 0c4b6dd1ca3..943f89eaa78 100644
> --- a/arch/arm/mach-sunxi/board.c
> +++ b/arch/arm/mach-sunxi/board.c
> @@ -347,10 +347,6 @@ u32 spl_boot_device(void)
> return sunxi_get_boot_device();
> }
>
> -__weak void sunxi_sram_init(void)
> -{
> -}
> -
> /*
> * When booting from an eMMC boot partition, the SPL puts the same boot
> * source code into SRAM A1 as when loading the SPL from the normal
> @@ -434,10 +430,20 @@ u32 spl_mmc_boot_mode(struct mmc *mmc, const u32 boot_device)
> return result;
> }
>
> +__weak void sunxi_sram_init(void)
> +{
> +}
> +
> +__weak void setup_arch_timer(void)
> +{
> +}
> +
> void board_init_f(ulong dummy)
> {
> sunxi_sram_init();
>
> + setup_arch_timer();
> +
> #if defined CONFIG_MACH_SUN6I || defined CONFIG_MACH_SUN8I_H3
> /* Enable non-secure access to some peripherals */
> tzpc_init();
> diff --git a/board/sunxi/board.c b/board/sunxi/board.c
> index 827e545032e..55501fafc38 100644
> --- a/board/sunxi/board.c
> +++ b/board/sunxi/board.c
> @@ -34,9 +34,6 @@
> #include <asm/global_data.h>
> #include <linux/delay.h>
> #include <u-boot/crc.h>
> -#ifndef CONFIG_ARM64
> -#include <asm/armv7.h>
> -#endif
> #include <asm/gpio.h>
> #include <asm/io.h>
> #include <u-boot/crc.h>
> @@ -187,39 +184,10 @@ enum env_location env_get_location(enum env_operation op, int prio)
> /* add board specific code here */
> int board_init(void)
> {
> - __maybe_unused int id_pfr1, ret, satapwr_pin, macpwr_pin;
> + int ret, satapwr_pin, macpwr_pin;
>
> gd->bd->bi_boot_params = (PHYS_SDRAM_0 + 0x100);
>
> -#if !defined(CONFIG_ARM64) && !defined(CONFIG_MACH_SUNIV)
> - asm volatile("mrc p15, 0, %0, c0, c1, 1" : "=r"(id_pfr1));
> - debug("id_pfr1: 0x%08x\n", id_pfr1);
> - /* Generic Timer Extension available? */
> - if ((id_pfr1 >> CPUID_ARM_GENTIMER_SHIFT) & 0xf) {
> - uint32_t freq;
> -
> - debug("Setting CNTFRQ\n");
> -
> - /*
> - * CNTFRQ is a secure register, so we will crash if we try to
> - * write this from the non-secure world (read is OK, though).
> - * In case some bootcode has already set the correct value,
> - * we avoid the risk of writing to it.
> - */
> - asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r"(freq));
> - if (freq != CONFIG_COUNTER_FREQUENCY) {
> - debug("arch timer frequency is %d Hz, should be %d, fixing ...\n",
> - freq, CONFIG_COUNTER_FREQUENCY);
> -#ifdef CONFIG_NON_SECURE
> - printf("arch timer frequency is wrong, but cannot adjust it\n");
> -#else
> - asm volatile("mcr p15, 0, %0, c14, c0, 0"
> - : : "r"(CONFIG_COUNTER_FREQUENCY));
> -#endif
> - }
> - }
> -#endif /* !CONFIG_ARM64 && !CONFIG_MACH_SUNIV */
> -
> ret = axp_gpio_init();
> if (ret)
> return ret;