[PATCH v4 1/7] ARM: S5PV210: Allow to probe whether workaround codes are required.

[Kukjin Kim]

MyungJoo Ham wrote:
> 
> Early products of S5PV210 had several errata that require kernel to
> avoid using some parts/instructions of the CPU or to add protection
> instructions. There are products with such early production CPUs;
> thus, we want to distinguish them in kernel. This patch is to
> distinguish such products.
> 
> Include <mach/hardware.h> and call s5pv210_workaround()
> 
> For example,
> 
> 	if (s5pv210_workaround()) {
> 		... execute workaround code ...
> 	} else {
> 		... execute normal code ...
> 	}
> 
> Where we can identify whether such workaround codes are required or not,
> call set_s5pv210_workaround_required() is it's needed. Note that in this
> system, it can be identified at board support file
> (arch/arm/mach-s5pv210/mach-*.c), not at the cpe file
> (arch/arm/mach-s5pv210/cpu.c). It is because we cannot determine based
> on the CPU_ID or PRODUCT_ID only; board revision number is required to
> determine.
> 
> For Aquila machine. (mach-aquila.c)
> 
> Part of Aquila machines have the early production CPUs that require
> to address errata issues. Note that we don't do this for GONI machines
> because they have never used early production CPUs with errata. Besides,
> please note that there are other boards that use such early produces
> other than Aquila. However, those boards/machines are not registered at
> the /linux/arch/arm/tools/mach-types, yet; thus, we have omitted them
> in this patch.

Hi,

Actually, I can't find any reason to need this 'workaround' function.
I think...this is for just EVT0, not workaround.

Please check my comments about your 7/7 patch.

> 
> Signed-off-by: MyungJoo Ham <myungjoo.ham at samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
> ---
>  arch/arm/mach-s5pv210/cpu.c                   |   33
> +++++++++++++++++++++++++
>  arch/arm/mach-s5pv210/include/mach/hardware.h |    3 +-
>  arch/arm/mach-s5pv210/mach-aquila.c           |    4 +++
>  3 files changed, 39 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/mach-s5pv210/cpu.c b/arch/arm/mach-s5pv210/cpu.c
> index 94c632b..b9fe38e 100644
> --- a/arch/arm/mach-s5pv210/cpu.c
> +++ b/arch/arm/mach-s5pv210/cpu.c
> @@ -24,6 +24,7 @@
>  #include <asm/mach/map.h>
>  #include <asm/mach/irq.h>
> 
> +#include <asm/mach-types.h>
>  #include <asm/proc-fns.h>
>  #include <mach/map.h>
>  #include <mach/regs-clock.h>
> @@ -128,6 +129,38 @@ static struct sys_device s5pv210_sysdev = {
>  	.cls	= &s5pv210_sysclass,
>  };
> 
> +/* See if workaround to avoid errata of earlier revisions */
> +static bool s5pv210_workaround_required;
> +
> +bool s5pv210_workaround(void)
> +{
> +	return s5pv210_workaround_required;
> +}
> +
> +void set_s5pv210_workaround(unsigned int board_rev)
> +{
> +	s5pv210_workaround_required = false;
> +
> +	if (machine_is_aquila()) {
> +		if (board_rev & 0x0800) {
> +			if ((board_rev & 0xF) < 8)
> +				s5pv210_workaround_required = true;
> +		} else if (board_rev & 0x2000) {
> +			s5pv210_workaround_required = true;
> +		}
> +	}
> +
> +	/*
> +	 * When machine_is_goni(), always false
> +	 *
> +	 * When machine_arch_number is 3260 and board_rev&0xF is 5,
> +	 *      always true. But, omitted as it's not registered at
> +	 *      mach_types, yet.
> +	 * When machine_arch_number is 3104 and board_rev&0xF is 0,
> +	 *      always true, as well. Omitted by the same reason.
> +	 */
> +}
> +
>  static int __init s5pv210_core_init(void)
>  {
>  	return sysdev_class_register(&s5pv210_sysclass);
> diff --git a/arch/arm/mach-s5pv210/include/mach/hardware.h
b/arch/arm/mach-
> s5pv210/include/mach/hardware.h
> index fada7a3..0c41852 100644
> --- a/arch/arm/mach-s5pv210/include/mach/hardware.h
> +++ b/arch/arm/mach-s5pv210/include/mach/hardware.h
> @@ -13,6 +13,7 @@
>  #ifndef __ASM_ARCH_HARDWARE_H
>  #define __ASM_ARCH_HARDWARE_H __FILE__
> 
> -/* currently nothing here, placeholder */
> +extern bool s5pv210_workaround(void);
> +extern void set_s5pv210_workaround(unsigned int);
> 
>  #endif /* __ASM_ARCH_HARDWARE_H */
> diff --git a/arch/arm/mach-s5pv210/mach-aquila.c
b/arch/arm/mach-s5pv210/mach-
> aquila.c
> index 46d5c7e..85024af 100644
> --- a/arch/arm/mach-s5pv210/mach-aquila.c
> +++ b/arch/arm/mach-s5pv210/mach-aquila.c
> @@ -30,6 +30,7 @@
>  #include <mach/regs-clock.h>
>  #include <mach/regs-fb.h>
>  #include <mach/gpio.h>
> +#include <mach/hardware.h>
> 
>  #include <plat/gpio-cfg.h>
>  #include <plat/regs-serial.h>
> @@ -536,6 +537,9 @@ static void __init aquila_map_io(void)
> 
>  static void __init aquila_machine_init(void)
>  {
> +	/* Determine whether we need workaround codes */
> +	set_s5pv210_workaround(system_rev);
> +
>  	/* PMIC */
>  	aquila_pmic_init();
>  	i2c_register_board_info(AP_I2C_GPIO_PMIC_BUS_4,
> i2c_gpio_pmic_devs,
> --


Thanks.

Best regards,
Kgene.
--
Kukjin Kim <kgene.kim at samsung.com>, Senior Engineer,
SW Solution Development Team, Samsung Electronics Co., Ltd.