Change in coreboot[master]: soc/sifive/fu540: Add helper function to get tlclk frequency

[Jonathan Neuschäfer (Code Review)]

Jonathan Neuschäfer has uploaded this change for review. ( https://review.coreboot.org/29335

Change subject: soc/sifive/fu540: Add helper function to get tlclk frequency
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soc/sifive/fu540: Add helper function to get tlclk frequency

tlclk is not specific to the UART block in the FU540, so let's calculate
its frequency in clock.c.

Change-Id: I270920027f1132253e413a1bf9feb4fe279b651a
Signed-off-by: Jonathan Neuschäfer 
---
M src/soc/sifive/fu540/clock.c
M src/soc/sifive/fu540/include/soc/clock.h
M src/soc/sifive/fu540/uart.c
3 files changed, 13 insertions(+), 5 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/35/29335/1

diff --git a/src/soc/sifive/fu540/clock.c b/src/soc/sifive/fu540/clock.c
index a8b61f1..edebe42 100644
--- a/src/soc/sifive/fu540/clock.c
+++ b/src/soc/sifive/fu540/clock.c
@@ -262,3 +262,14 @@
    	/ (divr + 1)
    	/ (1ul << divq);
 }
+
+/* Get the TileLink clock's frequency, in KHz */
+int clock_get_tlclk_khz(void)
+{
+	/*
+	 * The TileLink bus and most peripherals use tlclk, which is coreclk/2,
+	 * as input.
+	 */
+
+	return clock_get_coreclk_khz() / 2;
+}
diff --git a/src/soc/sifive/fu540/include/soc/clock.h b/src/soc/sifive/fu540/include/soc/clock.h
index d54c666..706c9c0 100644
--- a/src/soc/sifive/fu540/include/soc/clock.h
+++ b/src/soc/sifive/fu540/include/soc/clock.h
@@ -18,5 +18,6 @@

void clock_init(void);
 int clock_get_coreclk_khz(void);
+int clock_get_tlclk_khz(void);

#endif /* __SOC_SIFIVE_HIFIFE_U_CLOCK_H__ */
diff --git a/src/soc/sifive/fu540/uart.c b/src/soc/sifive/fu540/uart.c
index 454b13d..b59b789 100644
--- a/src/soc/sifive/fu540/uart.c
+++ b/src/soc/sifive/fu540/uart.c
@@ -29,9 +29,5 @@

unsigned int uart_platform_refclk(void)
 {
-	/*
-	 * The SiFive UART uses tlclk, which is coreclk/2, as input
-	 */
-
-	return clock_get_coreclk_khz() * KHz / 2;
+	return clock_get_tlclk_khz() * KHz;
 }