mediatek: Refactor SPI code among similar SOCs

Refactor SPI code which will be reused amon similar SOCs.

BUG=b:80501386
BRANCH=none
TEST=Boots correctly on Elm

Change-Id: If5a6c554dc8361e729cf5c464325b97b2bfb7098
Signed-off-by: Tristan Shieh <tristan.shieh@mediatek.com>
Reviewed-on: https://review.coreboot.org/27497
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

1 files changed, 261 insertions, 0 deletions

diff --git a/src/soc/mediatek/common/spi.c b/src/soc/mediatek/common/spi.c
new file mode 100644
index 0000000000..5d2dab4b04
--- /dev/null
+++ b/src/soc/mediatek/common/spi.c
@@ -0,0 +1,261 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2018 MediaTek Inc.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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.
+ */
+
+#include <arch/io.h>
+#include <assert.h>
+#include <endian.h>
+#include <stdlib.h>
+#include <soc/pll.h>
+#include <soc/spi.h>
+#include <timer.h>
+
+#define MTK_SPI_DEBUG 0
+
+enum {
+	MTK_FIFO_DEPTH = 32,
+	MTK_TXRX_TIMEOUT_US = 1000 * 1000,
+	MTK_ARBITRARY_VALUE = 0xdeaddead
+};
+
+enum {
+	MTK_SPI_IDLE = 0,
+	MTK_SPI_PAUSE_IDLE = 1
+};
+
+enum {
+	MTK_SPI_BUSY_STATUS = 1,
+	MTK_SPI_PAUSE_FINISH_INT_STATUS = 3
+};
+
+static inline struct mtk_spi_bus *to_mtk_spi(const struct spi_slave *slave)
+{
+	assert(slave->bus < SPI_BUS_NUMBER);
+	return &spi_bus[slave->bus];
+}
+
+static void spi_sw_reset(struct mtk_spi_regs *regs)
+{
+	setbits_le32(&regs->spi_cmd_reg, SPI_CMD_RST_EN);
+	clrbits_le32(&regs->spi_cmd_reg, SPI_CMD_RST_EN);
+}
+
+void mtk_spi_init(unsigned int bus, enum spi_pad_mask pad_select,
+		  unsigned int speed_hz)
+{
+	u32 div, sck_ticks, cs_ticks;
+
+	assert(bus < SPI_BUS_NUMBER);
+
+	struct mtk_spi_bus *slave = &spi_bus[bus];
+	struct mtk_spi_regs *regs = slave->regs;
+
+	if (speed_hz < SPI_HZ / 2)
+		div = div_round_up(SPI_HZ, speed_hz);
+	else
+		div = 1;
+
+	sck_ticks = div_round_up(div, 2);
+	cs_ticks = sck_ticks * 2;
+
+	printk(BIOS_DEBUG, "SPI%u(PAD%u) initialized at %u Hz\n",
+	       bus, pad_select, SPI_HZ / (sck_ticks * 2));
+
+	mtk_spi_set_timing(regs, sck_ticks, cs_ticks);
+
+	clrsetbits_le32(&regs->spi_cmd_reg,
+			(SPI_CMD_CPHA_EN | SPI_CMD_CPOL_EN |
+			 SPI_CMD_TX_ENDIAN_EN | SPI_CMD_RX_ENDIAN_EN |
+			 SPI_CMD_TX_DMA_EN | SPI_CMD_RX_DMA_EN |
+			 SPI_CMD_PAUSE_EN | SPI_CMD_DEASSERT_EN),
+			(SPI_CMD_TXMSBF_EN | SPI_CMD_RXMSBF_EN |
+			 SPI_CMD_FINISH_IE_EN | SPI_CMD_PAUSE_IE_EN));
+
+	mtk_spi_set_gpio_pinmux(bus, pad_select);
+
+	clrsetbits_le32(&regs->spi_pad_macro_sel_reg, SPI_PAD_SEL_MASK,
+			pad_select);
+}
+
+static void mtk_spi_dump_data(const char *name, const uint8_t *data, int size)
+{
+	if (MTK_SPI_DEBUG) {
+		int i;
+
+		printk(BIOS_DEBUG, "%s: 0x ", name);
+		for (i = 0; i < size; i++)
+			printk(BIOS_INFO, "%#x ", data[i]);
+		printk(BIOS_DEBUG, "\n");
+	}
+}
+
+static int spi_ctrlr_claim_bus(const struct spi_slave *slave)
+{
+	struct mtk_spi_bus *mtk_slave = to_mtk_spi(slave);
+	struct mtk_spi_regs *regs = mtk_slave->regs;
+
+	setbits_le32(&regs->spi_cmd_reg, 1 << SPI_CMD_PAUSE_EN_SHIFT);
+	mtk_slave->state = MTK_SPI_IDLE;
+
+	return 0;
+}
+
+static int do_transfer(const struct spi_slave *slave, void *in, const void *out,
+		       size_t *bytes_in, size_t *bytes_out)
+{
+	struct mtk_spi_bus *mtk_slave = to_mtk_spi(slave);
+	struct mtk_spi_regs *regs = mtk_slave->regs;
+	uint32_t reg_val = 0;
+	uint32_t i;
+	struct stopwatch sw;
+	size_t size;
+
+	if (*bytes_out == 0)
+		size = *bytes_in;
+	else if (*bytes_in == 0)
+		size = *bytes_out;
+	else
+		size = MIN(*bytes_in, *bytes_out);
+
+	clrsetbits_le32(&regs->spi_cfg1_reg,
+			SPI_CFG1_PACKET_LENGTH_MASK | SPI_CFG1_PACKET_LOOP_MASK,
+			((size - 1) << SPI_CFG1_PACKET_LENGTH_SHIFT) |
+			(0 << SPI_CFG1_PACKET_LOOP_SHIFT));
+
+	if (*bytes_out) {
+		const uint8_t *outb = (const uint8_t *)out;
+		for (i = 0; i < size; i++) {
+			reg_val |= outb[i] << ((i % 4) * 8);
+			if (i % 4 == 3) {
+				write32(&regs->spi_tx_data_reg, reg_val);
+				reg_val = 0;
+			}
+		}
+
+		if (i % 4 != 0)
+			write32(&regs->spi_tx_data_reg, reg_val);
+
+		mtk_spi_dump_data("the outb data is",
+				  (const uint8_t *)outb, size);
+	} else {
+		/* The SPI controller will transmit in full-duplex for RX,
+		 * therefore we need arbitrary data on MOSI which the slave
+		 * must ignore.
+		 */
+		uint32_t word_count = div_round_up(size, sizeof(u32));
+		for (i = 0; i < word_count; i++)
+			write32(&regs->spi_tx_data_reg, MTK_ARBITRARY_VALUE);
+	}
+
+	if (mtk_slave->state == MTK_SPI_IDLE) {
+		setbits_le32(&regs->spi_cmd_reg, SPI_CMD_ACT_EN);
+		mtk_slave->state = MTK_SPI_PAUSE_IDLE;
+	} else if (mtk_slave->state == MTK_SPI_PAUSE_IDLE) {
+		setbits_le32(&regs->spi_cmd_reg, SPI_CMD_RESUME_EN);
+	}
+
+	stopwatch_init_usecs_expire(&sw, MTK_TXRX_TIMEOUT_US);
+	while ((read32(&regs->spi_status1_reg) & MTK_SPI_BUSY_STATUS) == 0) {
+		if (stopwatch_expired(&sw)) {
+			printk(BIOS_ERR,
+			       "Timeout waiting for status1 status.\n");
+			goto error;
+		}
+	}
+	stopwatch_init_usecs_expire(&sw, MTK_TXRX_TIMEOUT_US);
+	while ((read32(&regs->spi_status0_reg) &
+	       MTK_SPI_PAUSE_FINISH_INT_STATUS) == 0) {
+		if (stopwatch_expired(&sw)) {
+			printk(BIOS_ERR,
+			       "Timeout waiting for status0 status.\n");
+			goto error;
+		}
+	}
+
+	if (*bytes_in) {
+		uint8_t *inb = (uint8_t *)in;
+		for (i = 0; i < size; i++) {
+			if (i % 4 == 0)
+				reg_val = read32(&regs->spi_rx_data_reg);
+			inb[i] = (reg_val >> ((i % 4) * 8)) & 0xff;
+		}
+		mtk_spi_dump_data("the inb data is", inb, size);
+
+		*bytes_in -= size;
+	}
+
+	if (*bytes_out)
+		*bytes_out -= size;
+
+	return 0;
+error:
+	spi_sw_reset(regs);
+	mtk_slave->state = MTK_SPI_IDLE;
+	return -1;
+}
+
+static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
+			  size_t bytes_out, void *din, size_t bytes_in)
+{
+	while (bytes_out || bytes_in) {
+		size_t in_now = MIN(bytes_in, MTK_FIFO_DEPTH);
+		size_t out_now = MIN(bytes_out, MTK_FIFO_DEPTH);
+		size_t in_rem = in_now;
+		size_t out_rem = out_now;
+
+		int ret = do_transfer(slave, din, dout, &in_rem, &out_rem);
+		if (ret != 0)
+			return ret;
+
+		if (bytes_out) {
+			size_t sent = out_now - out_rem;
+			bytes_out -= sent;
+			dout += sent;
+		}
+
+		if (bytes_in) {
+			size_t received = in_now - in_rem;
+			bytes_in -= received;
+			din += received;
+		}
+	}
+
+	return 0;
+}
+
+static void spi_ctrlr_release_bus(const struct spi_slave *slave)
+{
+	struct mtk_spi_bus *mtk_slave = to_mtk_spi(slave);
+	struct mtk_spi_regs *regs = mtk_slave->regs;
+
+	clrbits_le32(&regs->spi_cmd_reg, SPI_CMD_PAUSE_EN);
+	spi_sw_reset(regs);
+	mtk_slave->state = MTK_SPI_IDLE;
+}
+
+static int spi_ctrlr_setup(const struct spi_slave *slave)
+{
+	struct mtk_spi_bus *eslave = to_mtk_spi(slave);
+	assert(read32(&eslave->regs->spi_cfg0_reg) != 0);
+	spi_sw_reset(eslave->regs);
+	return 0;
+}
+
+const struct spi_ctrlr spi_ctrlr = {
+	.setup = spi_ctrlr_setup,
+	.claim_bus = spi_ctrlr_claim_bus,
+	.release_bus = spi_ctrlr_release_bus,
+	.xfer = spi_ctrlr_xfer,
+	.max_xfer_size = 65535,
+};