diff options
| author | Quinn Jensen <quinn.jensen@freescale.com> | 2007-05-24 18:23:44 -0600 |
|---|---|---|
| committer | Quinn Jensen <quinn.jensen@freescale.com> | 2007-05-24 18:23:44 -0600 |
| commit | 5d8e701238c30a8b2df8bc5b116fad8a41a3e89c (patch) | |
| tree | f96c34e145e7bd1f3cd147996d57cfa3c6ac2837 | |
| parent | 26e4293d9a31fc36ffcbf68118bb50e1251fa527 (diff) | |
Bugzilla 563: MX31 register swizzle work-around
A problem has been discovered with MX31-TO2 silicon where a general
register is loaded with an address constant from a PC-relative location.
Upon going indirect through this register, the address value contained
in the register will have been rotated right by 8 bits, causing a memory
fault. At present the cause of the rotation is not known.
This patch implements a work around to this problem, although why it
works is still unknown.
http://www.bitshrine.org/gpp/linux-2.6.19.2-mx31_TO2_reg_swizzle_workaround.patch
| -rw-r--r-- | arch/arm/plat-mxc/Kconfig | 14 | ||||
| -rw-r--r-- | drivers/mxc/pm/dvfs_dptc.c | 6 |
2 files changed, 20 insertions, 0 deletions
diff --git a/arch/arm/plat-mxc/Kconfig b/arch/arm/plat-mxc/Kconfig index d6f061142717..fd4f53228a38 100644 --- a/arch/arm/plat-mxc/Kconfig +++ b/arch/arm/plat-mxc/Kconfig @@ -11,6 +11,20 @@ config ARCH_MX3 help This enables support for systems based on Freescale i.MX31 +config MX31_TO2_REG_SWIZZLE_WORKAROUND + bool "MX31-TO2 Register Swizzle Workaround" + depends on ARCH_MX3 + help + This option attempts to work around a problem discovered with + MX31-TO2 silicon where a general register is loaded with an + address constant from a PC-relative location. Upon going + indirect through this register, the address value contained + in the register will have been rotated right by 8 bits, causing + a memory fault. The cause of the rotation is not known, nor is + the reason why this work around seems to make the problem go + away. If you are using MX31-TO2 silicon and are faulting on + rotated addresses, enable this option. + config ARCH_MX27 bool "MX27-based" select MXC_EMMA diff --git a/drivers/mxc/pm/dvfs_dptc.c b/drivers/mxc/pm/dvfs_dptc.c index 40c5a79d7b59..cbbd9b51ef46 100644 --- a/drivers/mxc/pm/dvfs_dptc.c +++ b/drivers/mxc/pm/dvfs_dptc.c @@ -422,7 +422,11 @@ static int __init dvfs_dptc_init_default_table(void) return -ENOMEM; } +#ifdef CONFIG_MX31_TO2_REG_SWIZZLE_WORKAROUND + table_str = default_table_str_rev2; +#else table_str = default_table_str; +#endif if (cpu_is_mx31()) { if (system_rev < CHIP_REV_2_0) { clk = clk_get(NULL, "ckih"); @@ -435,8 +439,10 @@ static int __init dvfs_dptc_init_default_table(void) } } else { #ifdef CONFIG_ARCH_MX3 +#ifndef CONFIG_MX31_TO2_REG_SWIZZLE_WORKAROUND table_str = default_table_str_rev2; #endif +#endif } clk_put(clk); } |