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authorSimon Glass <sjg@chromium.org>2016-09-05 11:04:50 -0600
committerPatrick Georgi <pgeorgi@google.com>2016-10-04 21:39:51 +0200
commit52669fc4dc4ab38e9ca61d65487fdfb809d3dd3d (patch)
treec0e40940e7f203741e3245f9fb3f45b0c0a99a86 /src/soc
parent7feb86b26b2b72d21098a90bff0843d8533a7493 (diff)
downloadcoreboot-52669fc4dc4ab38e9ca61d65487fdfb809d3dd3d.tar.xz
rockchip: spi: Set rxd sample delay when using high speed
At higher SPI bus speeds the SPI RX value is not available in time for sampling at the normal time. Add a delay to ensure that we read the correct data. The value of 40ns is chosen arbitrarily. In my testing I can use a sample delay of 1 even at 24MHz. But since it is not necessary, I have left that case alone. It kicks in at 25MHz and up. BUG=chrome-os-partner:56556 BRANCH=none TEST=boot on gru and see no change at current speed Change-Id: I3ef335d9a532eaef1e76034bd02e185acf11176a Signed-off-by: Patrick Georgi <pgeorgi@chromium.org> Original-Commit-Id: e9b620c47fc3e39211487507fadb8657afdebee7 Original-Change-Id: I65d66d752cbbbee4d02f475de23a52069a0e9782 Original-Signed-off-by: Simon Glass <sjg@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/381311 Original-Commit-Ready: Julius Werner <jwerner@chromium.org> Original-Tested-by: Simon Glass <sjg@google.com> Original-Reviewed-by: Julius Werner <jwerner@chromium.org> Reviewed-on: https://review.coreboot.org/16707 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Diffstat (limited to 'src/soc')
-rw-r--r--src/soc/rockchip/common/include/soc/spi.h3
-rw-r--r--src/soc/rockchip/common/spi.c18
2 files changed, 17 insertions, 4 deletions
diff --git a/src/soc/rockchip/common/include/soc/spi.h b/src/soc/rockchip/common/include/soc/spi.h
index dcaa4711d2..0e1847c985 100644
--- a/src/soc/rockchip/common/include/soc/spi.h
+++ b/src/soc/rockchip/common/include/soc/spi.h
@@ -199,4 +199,7 @@ check_member(rockchip_spi, rxdr, 0x800);
void rockchip_spi_init(unsigned int bus, unsigned int speed_hz);
+/* Set the receive sample delay in nanoseconds */
+void rockchip_spi_set_sample_delay(unsigned int bus, unsigned int delay_ns);
+
#endif /* ! __COREBOOT_SRC_SOC_ROCKCHIP_COMMON_INCLUDE_SOC_SPI_H */
diff --git a/src/soc/rockchip/common/spi.c b/src/soc/rockchip/common/spi.c
index f35f91589f..7dcaaadf19 100644
--- a/src/soc/rockchip/common/spi.c
+++ b/src/soc/rockchip/common/spi.c
@@ -32,7 +32,7 @@ struct rockchip_spi_slave {
};
#define SPI_TIMEOUT_US 1000
-#define SPI_SRCCLK_HZ (99*MHz)
+#define SPI_SRCCLK_HZ (198*MHz)
#define SPI_FIFO_DEPTH 32
static struct rockchip_spi_slave rockchip_spi_slaves[] = {
@@ -152,9 +152,6 @@ void rockchip_spi_init(unsigned int bus, unsigned int speed_hz)
/* Byte and Halfword Transform */
ctrlr0 |= (SPI_APB_8BIT << SPI_HALF_WORLD_TX_OFFSET);
- /* Rxd Sample Delay */
- ctrlr0 |= (0 << SPI_RXDSD_OFFSET);
-
/* Frame Format */
ctrlr0 |= (SPI_FRF_SPI << SPI_FRF_OFFSET);
@@ -165,6 +162,19 @@ void rockchip_spi_init(unsigned int bus, unsigned int speed_hz)
write32(&regs->rxftlr, SPI_FIFO_DEPTH / 2 - 1);
}
+void rockchip_spi_set_sample_delay(unsigned int bus, unsigned int delay_ns)
+{
+ assert(bus >= 0 && bus < ARRAY_SIZE(rockchip_spi_slaves));
+ struct rockchip_spi *regs = rockchip_spi_slaves[bus].regs;
+ unsigned int rsd;
+
+ /* Rxd Sample Delay */
+ rsd = DIV_ROUND_CLOSEST(delay_ns * (SPI_SRCCLK_HZ >> 8), 1*GHz >> 8);
+ assert(rsd >= 0 && rsd <= 3);
+ clrsetbits_le32(&regs->ctrlr0, SPI_RXDSD_MASK << SPI_RXDSD_OFFSET,
+ rsd << SPI_RXDSD_OFFSET);
+}
+
int spi_claim_bus(struct spi_slave *slave)
{
spi_cs_activate(slave);