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author | Lokesh Vutla <lokeshvutla@ti.com> | 2013-04-17 20:49:40 +0000 |
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committer | Tom Rini <trini@ti.com> | 2013-05-10 08:25:55 -0400 |
commit | 0b1b60c77954df19b5a601e2ba87614f2d0bbb8b (patch) | |
tree | 3dff44e2598611673743d56bd3480d9acf97b3f5 /arch/arm/include/asm/arch-omap4 | |
parent | 15191c91a240bd8683ca40e6c4b8b8c44b98412f (diff) | |
download | u-boot-imx-0b1b60c77954df19b5a601e2ba87614f2d0bbb8b.zip u-boot-imx-0b1b60c77954df19b5a601e2ba87614f2d0bbb8b.tar.gz u-boot-imx-0b1b60c77954df19b5a601e2ba87614f2d0bbb8b.tar.bz2 |
ARM: OMAP5: Fix warm reset with USB cable connected
Warm reset on OMAP5 freezes when USB cable is connected.
Fix requires PRM_RSTTIME.RSTTIME1 to be programmed
with the time for which reset should be held low for the
voltages and the oscillator to reach stable state.
There are 3 parameters to be considered for calculating
the time, which are mostly board and PMIC dependent.
-1- Time taken by the Oscillator to shut + restart
-2- PMIC OTP times
-3- Voltage rail ramp times, which inturn depends on the
PMIC slew rate and value of the voltage ramp needed.
In order to keep the code in u-boot simple, have a way
for boards to specify a pre computed time directly using
the 'CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC'
option. If boards fail to specify the time, use a default
as specified by 'CONFIG_DEFAULT_OMAP_RESET_TIME_MAX_USEC' instead.
Using the default value translates into some ~22ms and should work in
all cases.
However in order to avoid this large delay hiding other bugs,
its recommended that all boards look at their respective data
sheets and specify a pre computed and optimal value using
'CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC'
In order to help future board additions to compute this
config option value, add a README at doc/README.omap-reset-time
which explains how to compute the value. Also update the toplevel
README with the additional option and pointers to
doc/README.omap-reset-time.
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
[rnayak@ti.com: Updated changelog and added the README]
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Diffstat (limited to 'arch/arm/include/asm/arch-omap4')
-rw-r--r-- | arch/arm/include/asm/arch-omap4/sys_proto.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm/include/asm/arch-omap4/sys_proto.h b/arch/arm/include/asm/arch-omap4/sys_proto.h index d5f1868..ac9c1f8 100644 --- a/arch/arm/include/asm/arch-omap4/sys_proto.h +++ b/arch/arm/include/asm/arch-omap4/sys_proto.h @@ -58,6 +58,7 @@ void omap_vc_init(u16 speed_khz); int omap_vc_bypass_send_value(u8 sa, u8 reg_addr, u8 reg_data); u32 warm_reset(void); void force_emif_self_refresh(void); +void setup_warmreset_time(void); /* * This is used to verify if the configuration header * was executed by Romcode prior to control of transfer |