lm4: make CONFIG_UART_HOST optional

Currently, CONFIG_UART_HOST must be defined for all LM4-based
platforms.  Future platforms may not need host UART support, so make
it optional.

BUG=chrome-os-partner:22802
BRANCH=none
TEST=Temporarily comment out CONFIG_UART_HOST in board/link/board.h;
     code still compiles.

Change-Id: I8775d9daaf8f6e45f1f374c9be7f10316611447f
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/170104
Reviewed-by: Bill Richardson <wfrichar@chromium.org>

2 files changed, 36 insertions, 6 deletions

diff --git a/chip/lm4/lpc.c b/chip/lm4/lpc.c
index 71938409d8..9d0a53162f 100644
--- a/chip/lm4/lpc.c
+++ b/chip/lm4/lpc.c
@@ -266,6 +266,8 @@ void lpc_keyboard_resume_irq(void)
 		lpc_manual_irq(1);
 }
 
+#ifdef CONFIG_UART_HOST
+
 int lpc_comx_has_char(void)
 {
 	return LM4_LPC_ST(LPC_CH_COMX) & LM4_LPC_ST_FRMH;
@@ -282,6 +284,8 @@ void lpc_comx_put_char(int c)
 	/* TODO: manually trigger IRQ, like we do for keyboard? */
 }
 
+#endif /* CONFIG_UART_HOST */
+
 /**
  * Update the host event status.
  *
@@ -599,12 +603,14 @@ static void lpc_interrupt(void)
 	}
 #endif
 
+#ifdef CONFIG_UART_HOST
 	/* Handle COMx */
 	if (lpc_comx_has_char()) {
 		/* Copy a character to the UART if there's space */
 		if (uart_comx_putc_ok())
 			uart_comx_putc(lpc_comx_get_char());
 	}
+#endif
 
 	/* Debugging: print changes to LPC0RESET */
 	if (mis & (1 << 31)) {
@@ -731,6 +737,7 @@ static void lpc_init(void)
 	LM4_LPC_ADR(LPC_CH_MEMMAP) = EC_LPC_ADDR_MEMMAP;
 	LM4_LPC_CTL(LPC_CH_MEMMAP) = 0x0019 | (LPC_POOL_OFFS_MEMMAP << (5 - 1));
 
+#ifdef CONFIG_UART_HOST
 	/*
 	 * Set LPC channel 7 to COM port I/O address.  Note that channel 7
 	 * ignores the TYPE bit and is always an 8-byte range.
@@ -750,6 +757,7 @@ static void lpc_init(void)
 	 * sensible to buffer input anyway.
 	 */
 	LM4_LPC_LPCIM |= LM4_LPC_INT_MASK(LPC_CH_COMX, 2);
+#endif /* CONFIG_UART_HOST */
 
 	/*
 	 * Unmaksk LPC bus reset interrupt.  This lets us monitor the PCH
@@ -764,8 +772,11 @@ static void lpc_init(void)
 		(1 << LPC_CH_CMD_DATA) |
 		(1 << LPC_CH_KEYBOARD) |
 		(1 << LPC_CH_CMD) |
-		(1 << LPC_CH_MEMMAP) |
-		(1 << LPC_CH_COMX);
+		(1 << LPC_CH_MEMMAP);
+
+#ifdef CONFIG_UART_HOST
+	LM4_LPC_LPCCTL |= 1 << LPC_CH_COMX;
+#endif
 
 	/*
 	 * Ensure the EC (slave) has control of the memory-mapped I/O space.
@@ -793,8 +804,10 @@ static void lpc_init(void)
 	/* Enable LPC interrupt */
 	task_enable_irq(LM4_IRQ_LPC);
 
+#ifdef CONFIG_UART_HOST
 	/* Enable COMx UART */
 	uart_comx_enable();
+#endif
 
 	/* Restore event masks if needed */
 	lpc_post_sysjump();
diff --git a/chip/lm4/uart.c b/chip/lm4/uart.c
index ff24718a07..73570e1746 100644
--- a/chip/lm4/uart.c
+++ b/chip/lm4/uart.c
@@ -5,6 +5,7 @@
 
 /* UART module for Chrome EC */
 
+#include "clock.h"
 #include "common.h"
 #include "console.h"
 #include "gpio.h"
@@ -14,7 +15,9 @@
 #include "uart.h"
 #include "util.h"
 
+#ifdef CONFIG_UART_HOST
 #define CONFIG_UART_HOST_IRQ CONCAT2(LM4_IRQ_UART, CONFIG_UART_HOST)
+#endif
 
 static int init_done;
 
@@ -107,6 +110,8 @@ static void uart_ec_interrupt(void)
 }
 DECLARE_IRQ(LM4_IRQ_UART0, uart_ec_interrupt, 1);
 
+#ifdef CONFIG_UART_HOST
+
 /**
  * Interrupt handler for Host UART
  */
@@ -139,6 +144,8 @@ static void uart_host_interrupt(void)
 /* Must be same prio as LPC interrupt handler so they don't preempt */
 DECLARE_IRQ(CONFIG_UART_HOST_IRQ, uart_host_interrupt, 2);
 
+#endif /* CONFIG_UART_HOST */
+
 static void uart_config(int port)
 {
 	/* Disable the port */
@@ -173,17 +180,23 @@ static void uart_config(int port)
 
 void uart_init(void)
 {
-	volatile uint32_t scratch  __attribute__((unused));
-
 	/* Enable UART0 and Host UART and delay a few clocks */
-	LM4_SYSTEM_RCGCUART |= (1 << CONFIG_UART_HOST) | 1;
-	scratch = LM4_SYSTEM_RCGCUART;
+	LM4_SYSTEM_RCGCUART |= 1;
+
+#ifdef CONFIG_UART_HOST
+	LM4_SYSTEM_RCGCUART |= (1 << CONFIG_UART_HOST);
+#endif
+
+	clock_wait_cycles(3);
 
 	gpio_config_module(MODULE_UART, 1);
 
 	/* Configure UARTs (identically) */
 	uart_config(0);
+
+#ifdef CONFIG_UART_HOST
 	uart_config(CONFIG_UART_HOST);
+#endif
 
 	/*
 	 * Enable interrupts for UART0 only. Host UART will have to wait
@@ -198,6 +211,8 @@ void uart_init(void)
 /*****************************************************************************/
 /* COMx functions */
 
+#ifdef CONFIG_UART_HOST
+
 void uart_comx_enable(void)
 {
 	uart_clear_rx_fifo(CONFIG_UART_HOST);
@@ -223,6 +238,8 @@ void uart_comx_putc(int c)
 	LM4_UART_DR(CONFIG_UART_HOST) = c;
 }
 
+#endif /* CONFIG_UART_HOST */
+
 /*****************************************************************************/
 /* Console commands */