Re: [U-Boot] [PATCH] omap3: ARM Cortex-A8 errata workarounds config option

Hi Paul,

On 02/22/15 13:36, Paul Kocialkowski wrote:

Workarounds applied in omap3_setup_aux_cr are only necessary for ARM core revisions prior to r3p2 (such as OMAP35xx but apparently not OMAP36xx and DM37xx)

If this is true, I can see some (potential) problems with the patch. Please, check out my thoughts on this below.

and require similar workarounds in the kernel, or it will cause numerous segmentation faults. This allows (when the option is not used) properly booting kernels that do not include the workaround.

Follow-up to the discussion from July 2013: http://lists.denx.de/pipermail/u-boot/2013-July/158377.html

Signed-off-by: Paul Kocialkowski contact@paulk.fr

README | 8 ++++++++ arch/arm/cpu/armv7/omap3/board.c | 2 ++ include/configs/am3517_crane.h | 2 ++ include/configs/am3517_evm.h | 2 ++ include/configs/cm_t35.h | 2 ++ include/configs/cm_t3517.h | 2 ++ include/configs/dig297.h | 2 ++ include/configs/mcx.h | 2 ++ include/configs/nokia_rx51.h | 2 ++ include/configs/omap3_evm_common.h | 2 ++ include/configs/omap3_logic.h | 2 ++ include/configs/omap3_mvblx.h | 2 ++ include/configs/omap3_pandora.h | 2 ++ include/configs/omap3_sdp3430.h | 2 ++ include/configs/omap3_zoom1.h | 2 ++ include/configs/tam3517-common.h | 2 ++ include/configs/tao3530.h | 2 ++ include/configs/ti_omap3_common.h | 2 ++ include/configs/tricorder.h | 2 ++ 19 files changed, 44 insertions(+)

diff --git a/README b/README index ba57dc5..a39420d 100644 --- a/README +++ b/README @@ -621,6 +621,14 @@ The following options need to be configured: exists, unlike the similar options in the Linux kernel. Do not set these options unless they apply!

• CONFIG_SYS_ARM_CORTEXA8_ERRATA
  

• Enables workarounds for ARM Cortex-A8 errata 454179, 430973
  

• and 621766. This is only necessary for ARM core revisions prior
  

• to r3p2. Enabling those workarounds requires to enable the same
  

• workarounds in the kernel, or it will cause multiple
  

• segmentation faults. This is currently only effective on OMAP3.
  

• Driver Model Driver model is a new framework for devices in U-Boot introduced in early 2014. U-Boot is being progressively

diff --git a/arch/arm/cpu/armv7/omap3/board.c b/arch/arm/cpu/armv7/omap3/board.c index 90d6ae7..813f35b 100644 --- a/arch/arm/cpu/armv7/omap3/board.c +++ b/arch/arm/cpu/armv7/omap3/board.c @@ -246,8 +246,10 @@ void s_init(void)

try_unlock_memory();

+#ifdef CONFIG_SYS_ARM_CORTEXA8_ERRATA /* Errata workarounds */ omap3_setup_aux_cr();

Can we have the revision dynamically checked instead of/along with introducing a config option? We have boards, OMAP3 based, which are supported by the same board file and the same config file, see below.

+#endif

#ifndef CONFIG_SYS_L2CACHE_OFF /* Invalidate L2-cache from secure mode */

[...]

diff --git a/include/configs/cm_t35.h b/include/configs/cm_t35.h index b2a9f35..150b419 100644 --- a/include/configs/cm_t35.h +++ b/include/configs/cm_t35.h @@ -38,6 +38,8 @@ #define CONFIG_DISPLAY_CPUINFO #define CONFIG_DISPLAY_BOARDINFO

+#define CONFIG_SYS_ARM_CORTEXA8_ERRATA

This config file is used for both cm-t35 and cm-t3730. cm-t35 has OMAP3530, but cm-t3730 has DM3730. The same U-Boot binary is used for both boards.

/* Clock Defines */ #define V_OSCK 26000000 /* Clock output from T2 */ #define V_SCLK (V_OSCK >> 1)

[...]