soc/intel/apollolake: Enable decoding for ComA and ComB on LPC

If there is an external 8250 UART, one needs to enable the appropriate
address ranges before console_init() is called so that the init sequence
can reach the external UART.

Furthermore FSPM needs different settings for an external UART port. For
this, the function fill_console_params() has to be adapted.

Change-Id: I62c7d0b54edd18acf793849aef352afbcaeb68b9
Signed-off-by: Mario Scheithauer <mario.scheithauer@siemens.com>
Reviewed-on: https://review.coreboot.org/19693
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

2 files changed, 37 insertions, 9 deletions

diff --git a/src/soc/intel/apollolake/include/soc/lpc.h b/src/soc/intel/apollolake/include/soc/lpc.h
index 7e3d74aaf6..da918a16b4 100644
--- a/src/soc/intel/apollolake/include/soc/lpc.h
+++ b/src/soc/intel/apollolake/include/soc/lpc.h
@@ -29,8 +29,11 @@
  * IO decode enable macros are in the format IO_<peripheral>_<IO port>.
  * For example, to open ports 0x60, 0x64 for the keyboard controller,
  * use IOE_KBC_60_64 macro. For IOE_ macros that do not specify a port range,
- * the port range is selectable via the IO decodes register (not referenced).
+ * the port range is selectable via the IO decodes register.
  */
+#define REG_IO_DECODE			0x80
+#define  IOD_COMA_RANGE			(0 << 0) /* 0x3F8 - 0x3FF COMA*/
+#define  IOD_COMB_RANGE			(1 << 4) /* 0x2F8 - 0x2FF COMB*/
 #define REG_IO_ENABLES			0x82
 #define  IOE_EC_4E_4F			(1 << 13)
 #define  IOE_SUPERIO_2E_2F		(1 << 12)
diff --git a/src/soc/intel/apollolake/romstage.c b/src/soc/intel/apollolake/romstage.c
index 98c70156da..39d3989117 100644
--- a/src/soc/intel/apollolake/romstage.c
+++ b/src/soc/intel/apollolake/romstage.c
@@ -35,6 +35,7 @@
 #include <soc/cpu.h>
 #include <soc/intel/common/mrc_cache.h>
 #include <soc/iomap.h>
+#include <soc/lpc.h>
 #include <soc/systemagent.h>
 #include <soc/pci_devs.h>
 #include <soc/pm.h>
@@ -85,6 +86,18 @@ static void soc_early_romstage_init(void)
 	/* Enable decoding for HPET. Needed for FSP global pointer storage */
 	pci_write_config8(PCH_DEV_P2SB, P2SB_HPTC, P2SB_HPTC_ADDRESS_SELECT_0 |
 						P2SB_HPTC_ADDRESS_ENABLE);
+
+	if (IS_ENABLED(CONFIG_DRIVERS_UART_8250IO)) {
+		/*
+		 * I/O Decode Range Register for LPC
+		 * ComA Range 3F8h-3FFh [2:0]
+		 * ComB Range 2F8h-2FFh [6:4]
+		 */
+		pci_write_config16(PCH_DEV_LPC, REG_IO_DECODE,
+				IOD_COMA_RANGE | IOD_COMB_RANGE);
+		/* Enable ComA and ComB Port */
+		lpc_enable_fixed_io_ranges(IOE_COMA_EN | IOE_COMB_EN);
+	}
 }
 
 static void disable_watchdog(void)
@@ -245,14 +258,26 @@ asmlinkage void car_stage_entry(void)
 static void fill_console_params(FSPM_UPD *mupd)
 {
 	if (IS_ENABLED(CONFIG_CONSOLE_SERIAL)) {
-		mupd->FspmConfig.SerialDebugPortDevice =
-			CONFIG_UART_FOR_CONSOLE;
-		/* use MMIO port type */
-		mupd->FspmConfig.SerialDebugPortType = 2;
-		/* use 4 byte register stride */
-		mupd->FspmConfig.SerialDebugPortStrideSize = 2;
-		/* used only for port type set to external */
-		mupd->FspmConfig.SerialDebugPortAddress = 0;
+		if (IS_ENABLED(CONFIG_SOC_UART_DEBUG)) {
+			mupd->FspmConfig.SerialDebugPortDevice =
+					CONFIG_UART_FOR_CONSOLE;
+			/* use MMIO port type */
+			mupd->FspmConfig.SerialDebugPortType = 2;
+			/* use 4 byte register stride */
+			mupd->FspmConfig.SerialDebugPortStrideSize = 2;
+			/* used only for port type set to external */
+			mupd->FspmConfig.SerialDebugPortAddress = 0;
+		} else if (IS_ENABLED(CONFIG_DRIVERS_UART_8250IO)) {
+			/* use external UART for debug */
+			mupd->FspmConfig.SerialDebugPortDevice = 3;
+			/* use I/O port type */
+			mupd->FspmConfig.SerialDebugPortType = 1;
+			/* use 1 byte register stride */
+			mupd->FspmConfig.SerialDebugPortStrideSize = 0;
+			/* used only for port type set to external */
+			mupd->FspmConfig.SerialDebugPortAddress =
+					CONFIG_TTYS0_BASE;
+		}
 	} else {
 		mupd->FspmConfig.SerialDebugPortType = 0;
 	}