Change in coreboot[master]: soc/cavium/cn81xx/spi: Add function to return SPI clock

[Patrick Rudolph (Code Review)]

Patrick Rudolph has uploaded this change for review. ( https://review.coreboot.org/28789

Change subject: soc/cavium/cn81xx/spi: Add function to return SPI clock
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soc/cavium/cn81xx/spi: Add function to return SPI clock

Change-Id: I07c95b9ea14d47da0497470487fa3f162f8012c8
Signed-off-by: Patrick Rudolph 
---
M src/soc/cavium/cn81xx/include/soc/spi.h
M src/soc/cavium/cn81xx/spi.c
2 files changed, 22 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/89/28789/1

diff --git a/src/soc/cavium/cn81xx/include/soc/spi.h b/src/soc/cavium/cn81xx/include/soc/spi.h
index bb69daa..33f0f29 100644
--- a/src/soc/cavium/cn81xx/include/soc/spi.h
+++ b/src/soc/cavium/cn81xx/include/soc/spi.h
@@ -29,6 +29,7 @@
    	   const size_t speed_hz,
    	   const size_t idle_low,
    	   const size_t idle_cycles);
+uint64_t spi_get_clock(const size_t bus);
 void spi_set_lsbmsb(const size_t bus, const size_t lsb_first);
 void spi_init_custom(const size_t bus,
    	     const size_t speed_hz,
diff --git a/src/soc/cavium/cn81xx/spi.c b/src/soc/cavium/cn81xx/spi.c
index 5a5865e..6527f22 100644
--- a/src/soc/cavium/cn81xx/spi.c
+++ b/src/soc/cavium/cn81xx/spi.c
@@ -218,6 +218,27 @@
 }

/**
+ * Get current SPI clock frequency in Hz.
+ *
+ * @param bus                 The SPI bus to operate on
+ */
+uint64_t spi_get_clock(const size_t bus)
+{
+	union cavium_spi_cfg cfg;
+
+	assert(bus < ARRAY_SIZE(cavium_spi_slaves));
+	if (bus >= ARRAY_SIZE(cavium_spi_slaves))
+		return 0;
+
+	struct cavium_spi *regs = cavium_spi_slaves[bus].regs;
+	const uint64_t sclk = thunderx_get_io_clock();
+
+	cfg.u = read64(&regs->cfg);
+
+	return (sclk / (2ULL * cfg.s.clkdiv));
+}
+
+/**
  * Set SPI LSB/MSB first.
  *
  * @param bus                 The SPI bus to operate on