Simplify host event processing

Now both copies of the event state live in host_event_commands.c, and
lpc / memmap just shadows the main copy.

BUG=chrome-os-partner:11172
TEST=manual

Boot system.  should see events 0x2000, 0x80, 0x08 get set and then cleared.

At U-boot prompt, type on keyboard.  Should set event 0x1000 get set,
but only on the first keypress (because U-boot doesn't consume that
event).

Then from EC console,
hostevent clear 0x1000 -> see event 0x1000 clear
hostevent clear 0x1000 -> no debug output (it's already clear)
hostevent clearb 0x1000 -> see event copy B 0x1000 clear
hostevent clearb 0x1000 -> no debug output (copy B is already clear)

Change-Id: I855c035865649ba1490cd9027157d5bcdcc9895f
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/27321

5 files changed, 65 insertions, 62 deletions

diff --git a/chip/lm4/lpc.c b/chip/lm4/lpc.c
index 993208679d..597eb80f71 100644
--- a/chip/lm4/lpc.c
+++ b/chip/lm4/lpc.c
@@ -248,15 +248,13 @@ void lpc_comx_put_char(int c)
 }
 
 
-/* Update the host event status.
- * Sends a pulse if masked event status becomes non-zero:
- *  SMI pulse via EC_SMIn GPIO
- *  SCI pulse via LPC0SCI
+/**
+ * Update the host event status.  Sends a pulse if masked event status becomes
+ * non-zero:
+ *   - SMI pulse via EC_SMIn GPIO
+ *   - SCI pulse via LPC0SCI
  */
 static void update_host_event_status(void) {
-	uint32_t *mapped_raw_events =
-		(uint32_t *)host_get_memmap(EC_MEMMAP_HOST_EVENTS);
-
 	int need_sci = 0;
 	int need_smi = 0;
 
@@ -279,7 +277,7 @@ static void update_host_event_status(void) {
 		LM4_LPC_ST(LPC_CH_ACPI) &= ~LPC_STATUS_MASK_SCI;
 
 	/* Copy host events to mapped memory */
-	*mapped_raw_events = host_events;
+	*(uint32_t *)host_get_memmap(EC_MEMMAP_HOST_EVENTS) = host_events;
 
 	task_enable_irq(LM4_IRQ_LPC);
 
@@ -298,48 +296,25 @@ static void update_host_event_status(void) {
 		lpc_generate_sci();
 }
 
-
-void lpc_set_host_events(uint32_t mask)
-{
-	if ((host_events & mask) == mask)
-		return;
-
-	host_events |= mask;
-	CPRINTF("[%T event set 0x%08x -> %08x]\n", mask, host_events);
-	update_host_event_status();
-}
-
-
-void lpc_clear_host_events(uint32_t mask)
-{
-	if (!(host_events & mask))
-		return;
-
-	host_events &= ~mask;
-	CPRINTF("[%T event clear 0x%08x -> %08x]\n", mask, host_events);
-	update_host_event_status();
-}
-
-
-uint32_t lpc_get_host_events(void)
+void lpc_set_host_event_state(uint32_t mask)
 {
-	return host_events;
+	if (mask != host_events) {
+		host_events = mask;
+		update_host_event_status();
+	}
 }
 
-
 void lpc_set_host_event_mask(enum lpc_host_event_type type, uint32_t mask)
 {
 	event_mask[type] = mask;
 	update_host_event_status();
 }
 
-
 uint32_t lpc_get_host_event_mask(enum lpc_host_event_type type)
 {
 	return event_mask[type];
 }
 
-
 /* Handle an ACPI command */
 static void handle_acpi_command(void)
 {
@@ -361,7 +336,7 @@ static void handle_acpi_command(void)
 	case EC_CMD_ACPI_QUERY_EVENT:
 		for (i = 0; i < 32; i++) {
 			if (host_events & (1 << i)) {
-				lpc_clear_host_events(1 << i);
+				host_clear_events(1 << i);
 				result = i + 1;  /* Events are 1-based */
 				break;
 			}
diff --git a/common/console_output.c b/common/console_output.c
index e9f7bf0d97..e3334ee20d 100644
--- a/common/console_output.c
+++ b/common/console_output.c
@@ -22,6 +22,7 @@ static const char *channel_names[CC_CHANNEL_COUNT] = {
 	"charger",
 	"chipset",
 	"dma",
+	"events",
 	"gpio",
 	"hostcmd",
 	"i2c",
diff --git a/common/host_event_commands.c b/common/host_event_commands.c
index b4a161068a..670212c430 100644
--- a/common/host_event_commands.c
+++ b/common/host_event_commands.c
@@ -12,41 +12,59 @@
 #include "lpc.h"
 #include "util.h"
 
-/* Copy B of current events mask.
+/* Console output macros */
+#define CPUTS(outstr) cputs(CC_EVENTS, outstr)
+#define CPRINTF(format, args...) cprintf(CC_EVENTS, format, ## args)
+
+/*
+ * Maintain two copies of the events that are set.
+ *
+ * The primary copy is mirrored in mapped memory and used to trigger interrupts
+ * on the host via ACPI/SCI/SMI/GPIO.
  *
- * This is separate from the main copy, which affects ACPI/SCI/SMI/wake.
+ * The secondary (B) copy is used to track events at a non-interrupt level (for
+ * example, so a user-level process can find out what events have happened
+ * since the last call, even though a kernel-level process is consuming events
+ * from the first copy).
  *
- * Setting an event sets both copies.  Copies are cleared separately. */
+ * Setting an event sets both copies.  Copies are cleared separately.
+ */
+static uint32_t events;
 static uint32_t events_copy_b;
 
 uint32_t host_get_events(void)
 {
-#ifdef CONFIG_LPC
-	return lpc_get_host_events();
-#else
-	uint32_t *mapped_raw_events =
-		(uint32_t *)host_get_memmap(EC_MEMMAP_HOST_EVENTS);
-	return *mapped_raw_events;
-#endif
+	return events;
 }
 
 void host_set_events(uint32_t mask)
 {
+	/* Only print if something's about to change */
+	if ((events & mask) != mask || (events_copy_b & mask) != mask)
+		CPRINTF("[%T event set 0x%08x]\n", mask);
+
+	atomic_or(&events, mask);
 	atomic_or(&events_copy_b, mask);
 
 #ifdef CONFIG_LPC
-	lpc_set_host_events(mask);
+	lpc_set_host_event_state(events);
 #else
-	*(uint32_t *)host_get_memmap(EC_MEMMAP_HOST_EVENTS) |= mask;
+	*(uint32_t *)host_get_memmap(EC_MEMMAP_HOST_EVENTS) = events;
 #endif
 }
 
 void host_clear_events(uint32_t mask)
 {
+	/* Only print if something's about to change */
+	if (events & mask)
+		CPRINTF("[%T event clear 0x%08x]\n", mask);
+
+	atomic_clear(&events, mask);
+
 #ifdef CONFIG_LPC
-	lpc_clear_host_events(mask);
+	lpc_set_host_event_state(events);
 #else
-	*(uint32_t *)host_get_memmap(EC_MEMMAP_HOST_EVENTS) &= ~mask;
+	*(uint32_t *)host_get_memmap(EC_MEMMAP_HOST_EVENTS) = events;
 #endif
 }
 
@@ -58,6 +76,10 @@ void host_clear_events(uint32_t mask)
  */
 static void host_clear_events_b(uint32_t mask)
 {
+	/* Only print if something's about to change */
+	if (events_copy_b & mask)
+		CPRINTF("[%T event clear B 0x%08x]\n", mask);
+
 	atomic_clear(&events_copy_b, mask);
 }
 
diff --git a/include/console.h b/include/console.h
index 37d44bfc55..66bc5ba8e3 100644
--- a/include/console.h
+++ b/include/console.h
@@ -33,6 +33,7 @@ enum console_channel {
 	CC_CHARGER,
 	CC_CHIPSET,
 	CC_DMA,
+	CC_EVENTS,
 	CC_GPIO,
 	CC_HOSTCMD,
 	CC_I2C,
diff --git a/include/lpc.h b/include/lpc.h
index e9f5cad690..8c33b401b2 100644
--- a/include/lpc.h
+++ b/include/lpc.h
@@ -10,13 +10,16 @@
 
 #include "common.h"
 
-/* Manually generate an IRQ to host.
+/*
+ * Manually generate an IRQ to host.
  * Note that the irq_num == 0 would set the AH bit (Active High).
  */
 void lpc_manual_irq(int irq_num);
 
-/* Return a pointer to the memory-mapped buffer.  This buffer is writable at
- * any time, and the host can read it at any time. */
+/*
+ * Return a pointer to the memory-mapped buffer.  This buffer is writable at
+ * any time, and the host can read it at any time.
+ */
 uint8_t *lpc_get_memmap_range(void);
 
 /* Return true if the TOH is still set */
@@ -40,6 +43,13 @@ int lpc_comx_get_char(void);
 /* Put a character to the COMx LPC interface. */
 void lpc_comx_put_char(int c);
 
+/*
+ * Low-level LPC interface for host events.
+ *
+ * For use by host_event_commands.c.  Other modules should use the methods
+ * provided in host_command.h.
+ */
+
 /* Types of host events */
 enum lpc_host_event_type {
 	LPC_HOST_EVENT_SMI = 0,
@@ -47,14 +57,8 @@ enum lpc_host_event_type {
 	LPC_HOST_EVENT_WAKE,
 };
 
-/* Set one or more SCI/SMI event bits. */
-void lpc_set_host_events(uint32_t mask);
-
-/* Clear one or more SCI/SMI event bits.  Write 1 to a bit to clear it. */
-void lpc_clear_host_events(uint32_t mask);
-
-/* Return the raw SCI/SMI event state. */
-uint32_t lpc_get_host_events(void);
+/* Set the event state */
+void lpc_set_host_event_state(uint32_t mask);
 
 /* Set the event mask for the specified event type. */
 void lpc_set_host_event_mask(enum lpc_host_event_type type, uint32_t mask);