[PATCH linux dev-4.7] ARM: aspeed: witherspoon: Take UART1 out of reset
joel at jms.id.au
Mon May 1 17:48:36 AEST 2017
This is required so the UART can be used before booting the host.
Signed-off-by: Joel Stanley <joel at jms.id.au>
This is a workaround for manufacutring.
arch/arm/mach-aspeed/aspeed.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/arm/mach-aspeed/aspeed.c b/arch/arm/mach-aspeed/aspeed.c
index 0717181cc890..d2ffcf4c2c93 100644
@@ -216,6 +216,14 @@ static void __init do_witherspoon_setup(void)
/* Set SPI1 CE0 decoding window to 0x30000000 */
writel(0x68600000, AST_IO(AST_BASE_SPI | 0x30));
+ /* Disable default behavior of UART1 being held in reset by LPCRST#.
+ * By releasing UART1 from being controlled by LPC reset, it becomes
+ * immediately available regardless of the host being up.
+ reg = readl(AST_IO(AST_BASE_LPC | 0x98));
+ /* Clear "Enable UART1 reset source from LPC" */
+ writel(reg & ~BIT(4), AST_IO(AST_BASE_LPC | 0x98));
static void __init do_romulus_setup(void)
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