Tegra: spe: do not flush console in console_putc
SPE no longer requires the flush bit to be set to start transmitting
characters over the physical uart. Therefore, the flush bit is no
longer required when calling console_core_putc. However, flushing the
console still requires the flush bit.
This patch removes the flush bit from the mailbox messages in
console_core_putc to improve ACK latency.
Original change by: Mustafa Bilgen <mbilgen@nvidia.com>
Change-Id: I5b7d1f3ea69ea2ce308566dbaae222b04e4c373d
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
diff --git a/plat/nvidia/tegra/drivers/spe/shared_console.S b/plat/nvidia/tegra/drivers/spe/shared_console.S
index 6df73ec..9196c1c 100644
--- a/plat/nvidia/tegra/drivers/spe/shared_console.S
+++ b/plat/nvidia/tegra/drivers/spe/shared_console.S
@@ -11,8 +11,7 @@
#define CONSOLE_FLUSH_DATA_TO_PORT (1 << 26)
#define CONSOLE_RING_DOORBELL (1 << 31)
#define CONSOLE_IS_BUSY (1 << 31)
-#define CONSOLE_TIMEOUT 0xC000 /* approx. 50 ms */
-#define CONSOLE_WRITE (CONSOLE_RING_DOORBELL | CONSOLE_FLUSH_DATA_TO_PORT)
+#define CONSOLE_TIMEOUT 0xC000 /* 50 ms */
/*
* This file contains a driver implementation to make use of the
@@ -101,7 +100,7 @@
/* spe is ready */
mov w2, #0xD /* '\r' */
and w2, w2, #0xFF
- mov w3, #(CONSOLE_WRITE | (1 << CONSOLE_NUM_BYTES_SHIFT))
+ mov w3, #(CONSOLE_RING_DOORBELL | (1 << CONSOLE_NUM_BYTES_SHIFT))
orr w2, w2, w3
str w2, [x1]
@@ -111,7 +110,7 @@
/* spe is ready */
mov w2, w0
and w2, w2, #0xFF
- mov w3, #(CONSOLE_WRITE | (1 << CONSOLE_NUM_BYTES_SHIFT))
+ mov w3, #(CONSOLE_RING_DOORBELL | (1 << CONSOLE_NUM_BYTES_SHIFT))
orr w2, w2, w3
str w2, [x1]
@@ -164,7 +163,7 @@
cbz x0, flush_error
/* flush console */
- mov w1, #CONSOLE_WRITE
+ mov w1, #(CONSOLE_RING_DOORBELL | CONSOLE_FLUSH_DATA_TO_PORT)
str w1, [x0]
mov w0, #0
ret