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armv7/exynos5420: Revise SPI open/close/reset procedure. 

The original Exynos SPI open/close procedure was copied from U-Boot SPL with
some assumptions that only works in SPL stage.  For example, it tries to always
work in 4-byte transmission mode with only RX data is swapped, and claims a
packet for initial address command (and with incorrect size).

This commit revises open/close and reset so only the required SPI registers are
configured.

Change-Id: Ieba1f03d80a8949c39a6658218831ded39853744
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Signed-off-by: Gabe Black <gabeblack@chromium.org>
Reviewed-on: http://review.coreboot.org/3712
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
This commit is contained in:
Hung-Te Lin 2013-06-26 20:22:50 +08:00 committed by Stefan Reinauer
parent ed1742cafe
commit cab3621446
1 changed files with 39 additions and 37 deletions
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76
src/cpu/samsung/exynos5420/spi.c
View File

@ -102,6 +102,26 @@ void spi_cs_deactivate(struct spi_slave *slave)
setbits_le32(&regs->cs_reg, SPI_SLAVE_SIG_INACT);
}
static inline void exynos_spi_soft_reset(struct exynos_spi *regs)
{
/* The soft reset clears only FIFO and status register.
* All special function registers are not changed. */
setbits_le32(&regs->ch_cfg, SPI_CH_RST);
clrbits_le32(&regs->ch_cfg, SPI_CH_RST);
}
static inline void exynos_spi_flush_fifo(struct exynos_spi *regs)
{
/*
* Flush spi tx, rx fifos and reset the SPI controller
* and clear rx/tx channel
*/
clrbits_le32(&regs->ch_cfg, SPI_RX_CH_ON | SPI_TX_CH_ON);
clrbits_le32(&regs->ch_cfg, SPI_CH_HS_EN);
exynos_spi_soft_reset(regs);
setbits_le32(&regs->ch_cfg, SPI_RX_CH_ON | SPI_TX_CH_ON);
}
static void exynos_spi_rx_tx(struct exynos_spi *regs, int todo,
void *dinp, void const *doutp, int i)
{
@ -114,8 +134,7 @@ static void exynos_spi_rx_tx(struct exynos_spi *regs, int todo,
ASSERT(todo % 4 == 0);
out_bytes = in_bytes = todo;
setbits_le32(&regs->ch_cfg, SPI_CH_RST);
clrbits_le32(&regs->ch_cfg, SPI_CH_RST);
exynos_spi_soft_reset(regs);
writel(((todo * 8) / 32) | SPI_PACKET_CNT_EN, &regs->pkt_cnt);
while (in_bytes) {
@ -143,35 +162,27 @@ static void exynos_spi_rx_tx(struct exynos_spi *regs, int todo,
}
}
/* set up SPI channel */
int spi_claim_bus(struct spi_slave *slave)
{
struct exynos_spi_slave *espi = to_exynos_spi(slave);
struct exynos_spi *regs = espi->regs;
/* set the spi1 GPIO */
exynos_spi_flush_fifo(regs);
/* set pktcnt and enable it */
writel(4 | SPI_PACKET_CNT_EN, &regs->pkt_cnt);
/* set FB_CLK_SEL */
// Select Active High Clock, Format A (SCP 30.2.1.8).
clrbits_le32(&regs->ch_cfg, SPI_CH_CPOL_L | SPI_CH_CPHA_B);
// Set FeedBack Clock Selection.
writel(SPI_FB_DELAY_180, &regs->fb_clk);
/* set CH_WIDTH and BUS_WIDTH as word */
setbits_le32(&regs->mode_cfg,
SPI_MODE_CH_WIDTH_WORD | SPI_MODE_BUS_WIDTH_WORD);
clrbits_le32(&regs->ch_cfg, SPI_CH_CPOL_L); /* CPOL: active high */
/* clear rx and tx channel if set priveously */
clrbits_le32(&regs->ch_cfg, SPI_RX_CH_ON | SPI_TX_CH_ON);
setbits_le32(&regs->swap_cfg,
SPI_RX_SWAP_EN | SPI_RX_BYTE_SWAP | SPI_RX_HWORD_SWAP);
/* do a soft reset */
setbits_le32(&regs->ch_cfg, SPI_CH_RST);
clrbits_le32(&regs->ch_cfg, SPI_CH_RST);
/* now set rx and tx channel ON */
setbits_le32(&regs->ch_cfg, SPI_RX_CH_ON | SPI_TX_CH_ON | SPI_CH_HS_EN);
// HIGH speed is required for Tx/Rx to work in 50MHz (SCP 30.2.1.6).
if (espi->half_duplex) {
clrbits_le32(&regs->ch_cfg, SPI_CH_HS_EN);
printk(BIOS_DEBUG, "%s: LOW speed.\n", __func__);
} else {
setbits_le32(&regs->ch_cfg, SPI_CH_HS_EN);
printk(BIOS_DEBUG, "%s: HIGH speed.\n", __func__);
}
return 0;
}
@ -209,21 +220,12 @@ static int exynos_spi_read(struct spi_slave *slave, void *dest, uint32_t len,
void spi_release_bus(struct spi_slave *slave)
{
struct exynos_spi *regs = to_exynos_spi(slave)->regs;
/*
* Let put controller mode to BYTE as
* SPI driver does not support WORD mode yet
*/
clrbits_le32(&regs->mode_cfg,
SPI_MODE_CH_WIDTH_WORD | SPI_MODE_BUS_WIDTH_WORD);
/* Reset swap mode to make sure no one relying on default values (Ex,
* payload or kernel) will go wrong. */
clrbits_le32(&regs->mode_cfg, (SPI_MODE_CH_WIDTH_WORD |
SPI_MODE_BUS_WIDTH_WORD));
writel(0, &regs->swap_cfg);
/*
* Flush spi tx, rx fifos and reset the SPI controller
* and clear rx/tx channel
*/
clrsetbits_le32(&regs->ch_cfg, SPI_CH_HS_EN, SPI_CH_RST);
clrbits_le32(&regs->ch_cfg, SPI_CH_RST);
clrbits_le32(&regs->ch_cfg, SPI_TX_CH_ON | SPI_RX_CH_ON);
exynos_spi_flush_fifo(regs);
}
// SPI as CBFS media.