soc/qualcomm: Increase SPI frequency to 75 MHz

Increase frequency of sc7280 to 75 MHz.  Setting the delay to 1/8 of
a cycle as a result of experimentation.

BUG=b:190231148
BRANCH=None
TEST=Make sure that herobrine board boots
     HW Engineer measured SPI frequency and verified running at 75 MHz

Signed-off-by: Shelley Chen <shchen@google.com>
Change-Id: I3cf5a7c85f12800a11ece397a354349f2a0a235f
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64673
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 11 insertions, 1 deletions

diff --git a/src/soc/qualcomm/common/include/soc/qspi_common.h b/src/soc/qualcomm/common/include/soc/qspi_common.h
index a0f612c04f..6a1496aed1 100644
--- a/src/soc/qualcomm/common/include/soc/qspi_common.h
+++ b/src/soc/qualcomm/common/include/soc/qspi_common.h
@@ -26,6 +26,7 @@ struct qcom_qspi_regs {
 	u32 current_mem_addr;
 	u32 hw_version;
 	u32 rd_fifo[16];
+	u32 sampling_clk_cfg;
 };
 
 check_member(qcom_qspi_regs, rd_fifo, 0x50);
@@ -97,7 +98,16 @@ static struct qcom_qspi_regs * const qcom_qspi = (void *) QSPI_BASE;
 
 #define QSPI_MAX_PACKET_COUNT 0xFFC0
 
-void quadspi_init(uint32_t hz);
+/*
+ * quadspi_init(): Configure SPI
+ *
+ * @param hz:      SPI frequency in Hz
+ * @param sdelay:  sampling delay in sdelay/8 cycle units example, if sdelay=1,
+ *                 then will delay sampling clock by 1/8 cycle.  Note that
+ *                 setting sdelay to 4-7 would result in a negative sampling
+ *                 delay compared to 0.
+ */
+void quadspi_init(uint32_t hz, uint32_t sdelay);
 int qspi_claim_bus(const struct spi_slave *slave);
 int qspi_setup_bus(const struct spi_slave *slave);
 void qspi_release_bus(const struct spi_slave *slave);