--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 Stefan Roese <sr@denx.de>
+ *
+ * Derived from the Linux driver version drivers/spi/spi-mt7621.c
+ * Copyright (C) 2011 Sergiy <piratfm@gmail.com>
+ * Copyright (C) 2011-2013 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2014-2015 Felix Fietkau <nbd@nbd.name>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <spi.h>
+#include <wait_bit.h>
+#include <linux/io.h>
+
+#define SPI_MSG_SIZE_MAX 32 /* SPI message chunk size */
+/* Enough for SPI NAND page read / write with page size 2048 bytes */
+#define SPI_MSG_SIZE_OVERALL (2048 + 16)
+
+#define MT7621_SPI_TRANS 0x00
+#define MT7621_SPI_TRANS_START BIT(8)
+#define MT7621_SPI_TRANS_BUSY BIT(16)
+
+#define MT7621_SPI_OPCODE 0x04
+#define MT7621_SPI_DATA0 0x08
+#define MT7621_SPI_DATA4 0x18
+#define MT7621_SPI_MASTER 0x28
+#define MT7621_SPI_MOREBUF 0x2c
+#define MT7621_SPI_POLAR 0x38
+
+#define MT7621_LSB_FIRST BIT(3)
+#define MT7621_CPOL BIT(4)
+#define MT7621_CPHA BIT(5)
+
+#define MASTER_MORE_BUFMODE BIT(2)
+#define MASTER_RS_CLK_SEL GENMASK(27, 16)
+#define MASTER_RS_CLK_SEL_SHIFT 16
+#define MASTER_RS_SLAVE_SEL GENMASK(31, 29)
+
+struct mt7621_spi {
+ void __iomem *base;
+ unsigned int sys_freq;
+ u32 data[(SPI_MSG_SIZE_OVERALL / 4) + 1];
+ int tx_len;
+};
+
+static void mt7621_spi_reset(struct mt7621_spi *rs, int duplex)
+{
+ setbits_le32(rs->base + MT7621_SPI_MASTER,
+ MASTER_RS_SLAVE_SEL | MASTER_MORE_BUFMODE);
+}
+
+static void mt7621_spi_set_cs(struct mt7621_spi *rs, int cs, int enable)
+{
+ u32 val = 0;
+
+ debug("%s: cs#%d -> %s\n", __func__, cs, enable ? "enable" : "disable");
+ if (enable)
+ val = BIT(cs);
+ iowrite32(val, rs->base + MT7621_SPI_POLAR);
+}
+
+static int mt7621_spi_set_mode(struct udevice *bus, uint mode)
+{
+ struct mt7621_spi *rs = dev_get_priv(bus);
+ u32 reg;
+
+ debug("%s: mode=0x%08x\n", __func__, mode);
+ reg = ioread32(rs->base + MT7621_SPI_MASTER);
+
+ reg &= ~MT7621_LSB_FIRST;
+ if (mode & SPI_LSB_FIRST)
+ reg |= MT7621_LSB_FIRST;
+
+ reg &= ~(MT7621_CPHA | MT7621_CPOL);
+ switch (mode & (SPI_CPOL | SPI_CPHA)) {
+ case SPI_MODE_0:
+ break;
+ case SPI_MODE_1:
+ reg |= MT7621_CPHA;
+ break;
+ case SPI_MODE_2:
+ reg |= MT7621_CPOL;
+ break;
+ case SPI_MODE_3:
+ reg |= MT7621_CPOL | MT7621_CPHA;
+ break;
+ }
+ iowrite32(reg, rs->base + MT7621_SPI_MASTER);
+
+ return 0;
+}
+
+static int mt7621_spi_set_speed(struct udevice *bus, uint speed)
+{
+ struct mt7621_spi *rs = dev_get_priv(bus);
+ u32 rate;
+ u32 reg;
+
+ debug("%s: speed=%d\n", __func__, speed);
+ rate = DIV_ROUND_UP(rs->sys_freq, speed);
+ debug("rate:%u\n", rate);
+
+ if (rate > 4097)
+ return -EINVAL;
+
+ if (rate < 2)
+ rate = 2;
+
+ reg = ioread32(rs->base + MT7621_SPI_MASTER);
+ reg &= ~MASTER_RS_CLK_SEL;
+ reg |= (rate - 2) << MASTER_RS_CLK_SEL_SHIFT;
+ iowrite32(reg, rs->base + MT7621_SPI_MASTER);
+
+ return 0;
+}
+
+static inline int mt7621_spi_wait_till_ready(struct mt7621_spi *rs)
+{
+ int ret;
+
+ ret = wait_for_bit_le32(rs->base + MT7621_SPI_TRANS,
+ MT7621_SPI_TRANS_BUSY, 0, 10, 0);
+ if (ret)
+ pr_err("Timeout in %s!\n", __func__);
+
+ return ret;
+}
+
+static int mt7621_spi_xfer(struct udevice *dev, unsigned int bitlen,
+ const void *dout, void *din, unsigned long flags)
+{
+ struct udevice *bus = dev->parent;
+ struct mt7621_spi *rs = dev_get_priv(bus);
+ const u8 *tx_buf = dout;
+ u8 *ptr = (u8 *)dout;
+ u8 *rx_buf = din;
+ int total_size = bitlen >> 3;
+ int chunk_size;
+ int rx_len = 0;
+ u32 data[(SPI_MSG_SIZE_MAX / 4) + 1] = { 0 };
+ u32 val;
+ int i;
+
+ debug("%s: dout=%p, din=%p, len=%x, flags=%lx\n", __func__, dout, din,
+ total_size, flags);
+
+ /*
+ * This driver only supports half-duplex, so complain and bail out
+ * upon full-duplex messages
+ */
+ if (dout && din) {
+ printf("Only half-duplex SPI transfer supported\n");
+ return -EIO;
+ }
+
+ if (dout) {
+ debug("TX-DATA: ");
+ for (i = 0; i < total_size; i++)
+ debug("%02x ", *ptr++);
+ debug("\n");
+ }
+
+ mt7621_spi_wait_till_ready(rs);
+
+ /*
+ * Set CS active upon start of SPI message. This message can
+ * be split upon multiple calls to this xfer function
+ */
+ if (flags & SPI_XFER_BEGIN)
+ mt7621_spi_set_cs(rs, spi_chip_select(dev), 1);
+
+ while (total_size > 0) {
+ /* Don't exceed the max xfer size */
+ chunk_size = min_t(int, total_size, SPI_MSG_SIZE_MAX);
+
+ /*
+ * We might have some TX data buffered from the last xfer
+ * message. Make sure, that this does not exceed the max
+ * xfer size
+ */
+ if (rs->tx_len > 4)
+ chunk_size -= rs->tx_len;
+ if (din)
+ rx_len = chunk_size;
+
+ if (tx_buf) {
+ /* Check if this message does not exceed the buffer */
+ if ((chunk_size + rs->tx_len) > SPI_MSG_SIZE_OVERALL) {
+ printf("TX message size too big (%d)\n",
+ chunk_size + rs->tx_len);
+ return -EMSGSIZE;
+ }
+
+ /*
+ * Write all TX data into internal buffer to collect
+ * all TX messages into one buffer (might be split into
+ * multiple calls to this function)
+ */
+ for (i = 0; i < chunk_size; i++, rs->tx_len++) {
+ rs->data[rs->tx_len / 4] |=
+ tx_buf[i] << (8 * (rs->tx_len & 3));
+ }
+ }
+
+ if (flags & SPI_XFER_END) {
+ /* Write TX data into controller */
+ if (rs->tx_len) {
+ rs->data[0] = swab32(rs->data[0]);
+ if (rs->tx_len < 4)
+ rs->data[0] >>= (4 - rs->tx_len) * 8;
+
+ for (i = 0; i < rs->tx_len; i += 4) {
+ iowrite32(rs->data[i / 4], rs->base +
+ MT7621_SPI_OPCODE + i);
+ }
+ }
+
+ /* Write length into controller */
+ val = (min_t(int, rs->tx_len, 4) * 8) << 24;
+ if (rs->tx_len > 4)
+ val |= (rs->tx_len - 4) * 8;
+ val |= (rx_len * 8) << 12;
+ iowrite32(val, rs->base + MT7621_SPI_MOREBUF);
+
+ /* Start the xfer */
+ setbits_le32(rs->base + MT7621_SPI_TRANS,
+ MT7621_SPI_TRANS_START);
+
+ /* Wait until xfer is finished on bus */
+ mt7621_spi_wait_till_ready(rs);
+
+ /* Reset TX length and TX buffer for next xfer */
+ rs->tx_len = 0;
+ memset(rs->data, 0, sizeof(rs->data));
+ }
+
+ for (i = 0; i < rx_len; i += 4)
+ data[i / 4] = ioread32(rs->base + MT7621_SPI_DATA0 + i);
+
+ if (rx_len) {
+ debug("RX-DATA: ");
+ for (i = 0; i < rx_len; i++) {
+ rx_buf[i] = data[i / 4] >> (8 * (i & 3));
+ debug("%02x ", rx_buf[i]);
+ }
+ debug("\n");
+ }
+
+ if (tx_buf)
+ tx_buf += chunk_size;
+ if (rx_buf)
+ rx_buf += chunk_size;
+ total_size -= chunk_size;
+ }
+
+ /* Wait until xfer is finished on bus and de-assert CS */
+ mt7621_spi_wait_till_ready(rs);
+ if (flags & SPI_XFER_END)
+ mt7621_spi_set_cs(rs, spi_chip_select(dev), 0);
+
+ return 0;
+}
+
+static int mt7621_spi_probe(struct udevice *dev)
+{
+ struct mt7621_spi *rs = dev_get_priv(dev);
+
+ rs->base = dev_remap_addr(dev);
+ if (!rs->base)
+ return -EINVAL;
+
+ /*
+ * Read input clock via DT for now. At some point this should be
+ * replaced by implementing a clock driver for this SoC and getting
+ * the SPI frequency via this clock driver.
+ */
+ rs->sys_freq = dev_read_u32_default(dev, "clock-frequency", 0);
+ if (!rs->sys_freq) {
+ printf("Please provide clock-frequency!\n");
+ return -EINVAL;
+ }
+
+ mt7621_spi_reset(rs, 0);
+
+ return 0;
+}
+
+static const struct dm_spi_ops mt7621_spi_ops = {
+ .set_mode = mt7621_spi_set_mode,
+ .set_speed = mt7621_spi_set_speed,
+ .xfer = mt7621_spi_xfer,
+ /*
+ * cs_info is not needed, since we require all chip selects to be
+ * in the device tree explicitly
+ */
+};
+
+static const struct udevice_id mt7621_spi_ids[] = {
+ { .compatible = "ralink,mt7621-spi" },
+ { }
+};
+
+U_BOOT_DRIVER(mt7621_spi) = {
+ .name = "mt7621_spi",
+ .id = UCLASS_SPI,
+ .of_match = mt7621_spi_ids,
+ .ops = &mt7621_spi_ops,
+ .priv_auto_alloc_size = sizeof(struct mt7621_spi),
+ .probe = mt7621_spi_probe,
+};
projects / u-boot.git / commitdiff
