diff options
| author | Anson Huang <Anson.Huang@nxp.com> | 2016-01-10 00:38:37 +0800 |
|---|---|---|
| committer | Jason Liu <jason.hui.liu@nxp.com> | 2019-02-12 10:31:19 +0800 |
| commit | 6d35143b05d241066f580b5a69fbdfe46120ff0f (patch) | |
| tree | d34635cda42a287d40f53f95b31cceccb8a0ead3 /arch/arm/mach-imx | |
| parent | 7964004a646886b10ecaa2e62b67c3a260c446e7 (diff) | |
MLK-12203-2 ARM: imx: adjust loop number to delay ~20us for i.MX7D low power idle
ARM does NOT execute one instruction every cycle, the bus bandwidth,
cache status etc. would impacts the instruction execution time, so we
can NOT just calculate the delay time by ARM frequency, this patch
adjusts loop number to get a ~20us delay, measured via GPIO pin.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Diffstat (limited to 'arch/arm/mach-imx')
| -rw-r--r-- | arch/arm/mach-imx/imx7d_low_power_idle.S | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/arm/mach-imx/imx7d_low_power_idle.S b/arch/arm/mach-imx/imx7d_low_power_idle.S index 2cc088df569f..07460dde6925 100644 --- a/arch/arm/mach-imx/imx7d_low_power_idle.S +++ b/arch/arm/mach-imx/imx7d_low_power_idle.S @@ -278,8 +278,8 @@ ldr r7, =0xf0000 str r7, [r10] - /* assume ARM @ 1GHz, about delay 20us */ - ldr r7, =10000 + /* delay 20us, measured by gpio */ + ldr r7, =20 12: subs r7, r7, #0x1 bne 12b @@ -296,7 +296,7 @@ ldr r7, =0x0 str r7, [r10] - ldr r7, =10000 + ldr r7, =20 13: subs r7, r7, #0x1 bne 13b |