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authorSubrata Banik <subrata.banik@intel.com>2017-08-10 13:57:07 +0530
committerAaron Durbin <adurbin@chromium.org>2017-08-16 23:29:56 +0000
commitb27aa82a50cde46d43ea0dd6ad797eb9c248e6c8 (patch)
tree314c8bcf0ec0ce4c02997dabf9d3a98d94f87ed0 /src
parentf710955b93dddb094b9dacf651fe8a0730b21500 (diff)
downloadcoreboot-b27aa82a50cde46d43ea0dd6ad797eb9c248e6c8.tar.xz
soc/intel/skylake: Add proper support to enable UART2 in 16550 mode
Need to perform a dummy read in order to activate LPSS UART's 16550 8-bit compatibility mode. TEST=Able to get serial log in both 32 bit and 8 bit mode through LPSS UART2 based on CONFIG_DRIVERS_UART_8250MEM_32 and CONFIG_DRIVERS_UART_8250MEM selection. Change-Id: I5f23fef4522743efd49167afb04d56032e16e417 Signed-off-by: Subrata Banik <subrata.banik@intel.com> Reviewed-on: https://review.coreboot.org/20939 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Diffstat (limited to 'src')
-rw-r--r--src/soc/intel/skylake/bootblock/uart.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/src/soc/intel/skylake/bootblock/uart.c b/src/soc/intel/skylake/bootblock/uart.c
index b7ab241f77..f6e7e13b8e 100644
--- a/src/soc/intel/skylake/bootblock/uart.c
+++ b/src/soc/intel/skylake/bootblock/uart.c
@@ -27,9 +27,7 @@
/* Serial IO UART controller legacy mode */
#define PCR_SERIAL_IO_GPPRVRW7 0x618
-#define PCR_SIO_PCH_LEGACY_UART0 (1 << 0)
-#define PCR_SIO_PCH_LEGACY_UART1 (1 << 1)
-#define PCR_SIO_PCH_LEGACY_UART2 (1 << 2)
+#define PCR_SIO_PCH_LEGACY_UART(idx) (1 << (idx))
/* UART2 pad configuration. Support RXD and TXD for now. */
static const struct pad_config uart2_pads[] = {
@@ -44,9 +42,16 @@ void pch_uart_init(void)
uart_common_init(PCH_DEV_UART2, base);
/* Put UART2 in byte access mode for 16550 compatibility */
- if (!IS_ENABLED(CONFIG_DRIVERS_UART_8250MEM_32))
+ if (!IS_ENABLED(CONFIG_DRIVERS_UART_8250MEM_32)) {
pcr_write32(PID_SERIALIO, PCR_SERIAL_IO_GPPRVRW7,
- PCR_SIO_PCH_LEGACY_UART2);
+ PCR_SIO_PCH_LEGACY_UART(CONFIG_UART_FOR_CONSOLE));
+
+ /*
+ * Dummy read after setting any of GPPRVRW7.
+ * Required for UART 16550 8-bit Legacy mode to become active
+ */
+ lpss_clk_read(base);
+ }
gpio_configure_pads(uart2_pads, ARRAY_SIZE(uart2_pads));
}