armv7: Add SPI driver for Exynos.

The SPI flash driver for Exynos chipset.

Verified to boot on snow/armv7.

Change-Id: I7eef67a9c57f825d09f13ea44c2b59b54345fa7b
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: http://review.coreboot.org/2229
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

2 files changed, 246 insertions, 3 deletions

diff --git a/src/cpu/samsung/exynos5-common/spi.c b/src/cpu/samsung/exynos5-common/spi.c
index e13eadf3fe..90b74c018f 100644
--- a/src/cpu/samsung/exynos5-common/spi.c
+++ b/src/cpu/samsung/exynos5-common/spi.c
@@ -1,7 +1,237 @@
-#include <cbfs.h>
+/*
+ * Copyright (C) 2011 Samsung Electronics
+ * Copyright (C) 2013 The Chromium OS Authors. All rights reserved.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
 
-/* TODO provide a real SPI driver here for firmware media. */
+#include <stdlib.h>
+
+#include <common.h>
+#include <console/console.h>
+
+#include <cpu/samsung/exynos5250/gpio.h>
+#include <cpu/samsung/exynos5250/clk.h>
+
+#include "spi.h"
+
+#define OM_STAT		(0x1f << 1)
+#define EXYNOS_BASE_SPI1 ((void *)0x12d30000)
+
+#if defined(CONFIG_DEBUG_SPI) && CONFIG_DEBUG_SPI
+# define DEBUG_SPI(x,...)	printk(BIOS_DEBUG, "EXYNOS_SPI: " x)
+#else
+# define DEBUG_SPI(x,...)
+#endif
+
+static void exynos_spi_rx_tx(struct exynos_spi *regs, int todo,
+			     void *dinp, void const *doutp, int i)
+{
+	int rx_lvl, tx_lvl;
+	uint *rxp = (uint *)(dinp + (i * (32 * 1024)));
+	uint out_bytes, in_bytes;
+
+	// TODO In currrent implementation, every read/write must be aligned to
+	// 4 bytes, otherwise you may get timeout or other unexpected results.
+	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);
+	writel(((todo * 8) / 32) | SPI_PACKET_CNT_EN, &regs->pkt_cnt);
+
+	while (in_bytes) {
+		uint32_t spi_sts;
+		int temp;
+
+		spi_sts = readl(&regs->spi_sts);
+		rx_lvl = ((spi_sts >> 15) & 0x7f);
+		tx_lvl = ((spi_sts >> 6) & 0x7f);
+		while (tx_lvl < 32 && out_bytes) {
+			// TODO The "writing" (tx) is not supported now; that's
+			// why we write garbage to keep driving FIFO clock.
+			temp = 0xffffffff;
+			writel(temp, &regs->tx_data);
+			out_bytes -= 4;
+			tx_lvl += 4;
+		}
+		while (rx_lvl >= 4 && in_bytes) {
+			temp = readl(&regs->rx_data);
+			if (rxp)
+				*rxp++ = temp;
+			in_bytes -= 4;
+			rx_lvl -= 4;
+		}
+	}
+}
+
+int exynos_spi_open(struct exynos_spi *regs)
+{
+	clock_set_rate(PERIPH_ID_SPI1, 50000000); /* set spi clock to 50Mhz */
+	/* set the spi1 GPIO */
+
+	// TODO Some of these should be done in board's bootblock file.
+	// We should fix-up the mainboard-specific vs. exynos-specific parts in a
+	// follow-up CL.
+
+//	exynos_pinmux_config(PERIPH_ID_SPI1, PINMUX_FLAG_NONE);
+	gpio_cfg_pin(GPIO_A24, 0x2);
+	gpio_cfg_pin(GPIO_A25, 0x2);
+	gpio_cfg_pin(GPIO_A26, 0x2);
+	gpio_cfg_pin(GPIO_A27, 0x2);
+
+	/* set pktcnt and enable it */
+	writel(4 | SPI_PACKET_CNT_EN, &regs->pkt_cnt);
+	/* set FB_CLK_SEL */
+	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);
+	clrbits_le32(&regs->cs_reg, SPI_SLAVE_SIG_INACT); /* CS low */
+	return 0;
+}
+
+int exynos_spi_read(struct exynos_spi *regs, void *dest, u32 len, u32 off)
+{
+	int upto, todo;
+	int i;
+	/* Send read instruction (0x3h) followed by a 24 bit addr */
+	writel((SF_READ_DATA_CMD << 24) | off, &regs->tx_data);
+
+	/* waiting for TX done */
+	while (!(readl(&regs->spi_sts) & SPI_ST_TX_DONE));
+
+	for (upto = 0, i = 0; upto < len; upto += todo, i++) {
+		todo = MIN(len - upto, (1 << 15));
+		exynos_spi_rx_tx(regs, todo, dest, (void *)(off), i);
+	}
+
+	setbits_le32(&regs->cs_reg, SPI_SLAVE_SIG_INACT);/* make the CS high */
+
+	/*
+	 * 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);
+	writel(0, &regs->swap_cfg);
+
+	return len;
+}
+
+int exynos_spi_close(struct exynos_spi *regs)
+{
+	/*
+	 * 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);
+	return 0;
+}
+
+// SPI as CBFS media.
+struct exynos_spi_media {
+	struct exynos_spi *regs;
+	struct cbfs_simple_buffer buffer;
+};
+
+static int exynos_spi_cbfs_open(struct cbfs_media *media) {
+	struct exynos_spi_media *spi = (struct exynos_spi_media*)media->context;
+	DEBUG_SPI("exynos_spi_cbfs_open\n");
+	return exynos_spi_open(spi->regs);
+}
+
+static int exynos_spi_cbfs_close(struct cbfs_media *media) {
+	struct exynos_spi_media *spi = (struct exynos_spi_media*)media->context;
+	DEBUG_SPI("exynos_spi_cbfs_close\n");
+	return exynos_spi_close(spi->regs);
+}
+
+static size_t exynos_spi_cbfs_read(struct cbfs_media *media, void *dest,
+				   size_t offset, size_t count) {
+	struct exynos_spi_media *spi = (struct exynos_spi_media*)media->context;
+	int bytes;
+	DEBUG_SPI("exynos_spi_cbfs_read(%u)\n", count);
+	bytes = exynos_spi_read(spi->regs, dest, count, offset);
+	// Flush and re-open the device.
+	exynos_spi_close(spi->regs);
+	exynos_spi_open(spi->regs);
+	return bytes;
+}
+
+static void *exynos_spi_cbfs_map(struct cbfs_media *media, size_t offset,
+				 size_t count) {
+	struct exynos_spi_media *spi = (struct exynos_spi_media*)media->context;
+	DEBUG_SPI("exynos_spi_cbfs_map\n");
+	// See exynos_spi_rx_tx for I/O alignment limitation.
+	if (count % 4)
+		count += 4 - (count % 4);
+	return cbfs_simple_buffer_map(&spi->buffer, media, offset, count);
+}
+
+static void *exynos_spi_cbfs_unmap(struct cbfs_media *media,
+				   const void *address) {
+	struct exynos_spi_media *spi = (struct exynos_spi_media*)media->context;
+	DEBUG_SPI("exynos_spi_cbfs_unmap\n");
+	return cbfs_simple_buffer_unmap(&spi->buffer, address);
+}
+
+int initialize_exynos_spi_cbfs_media(struct cbfs_media *media,
+				     void *buffer_address,
+				     size_t buffer_size) {
+	// TODO Replace static variable to support multiple streams.
+	static struct exynos_spi_media context;
+	DEBUG_SPI("initialize_exynos_spi_cbfs_media\n");
+
+	context.regs = EXYNOS_BASE_SPI1;
+	context.buffer.allocated = context.buffer.last_allocate = 0;
+	context.buffer.buffer = buffer_address;
+	context.buffer.size = buffer_size;
+	media->context = (void*)&context;
+	media->open = exynos_spi_cbfs_open;
+	media->close = exynos_spi_cbfs_close;
+	media->read = exynos_spi_cbfs_read;
+	media->map = exynos_spi_cbfs_map;
+	media->unmap = exynos_spi_cbfs_unmap;
+
+	return 0;
+}
 
 int init_default_cbfs_media(struct cbfs_media *media) {
-	return -1;
+	return initialize_exynos_spi_cbfs_media(
+			media,
+			(void*)CONFIG_CBFS_CACHE_ADDRESS,
+			CONFIG_CBFS_CACHE_SIZE);
 }
diff --git a/src/cpu/samsung/exynos5-common/spi.h b/src/cpu/samsung/exynos5-common/spi.h
index 3f3675921c..e021888614 100644
--- a/src/cpu/samsung/exynos5-common/spi.h
+++ b/src/cpu/samsung/exynos5-common/spi.h
@@ -22,6 +22,9 @@
 
 #ifndef __ASSEMBLER__
 
+// This driver serves as a CBFS media source.
+#include <cbfs.h>
+
 /* SPI peripheral register map; padded to 64KB */
 struct exynos_spi {
 	unsigned int		ch_cfg;		/* 0x00 */
@@ -85,5 +88,15 @@ struct exynos_spi {
 #define SPI_RX_BYTE_SWAP	(1 << 6)
 #define SPI_RX_HWORD_SWAP	(1 << 7)
 
+/* API */
+int exynos_spi_open(struct exynos_spi *regs);
+int exynos_spi_read(struct exynos_spi *regs, void *dest, u32 len, u32 off);
+int exynos_spi_close(struct exynos_spi *regs);
+
+/* Serve as CBFS Media */
+int initialize_exynos_spi_cbfs_media(struct cbfs_media *media,
+				     void *buffer_address,
+				     size_t buffer_size);
+
 #endif /* __ASSEMBLER__ */
 #endif