--- /dev/null
+/*
+ * SPI-Engine SPI controller driver
+ * Copyright 2015 Analog Devices Inc.
+ * Author: Lars-Peter Clausen <lars@metafoo.de>
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+
+#define SPI_ENGINE_VERSION_MAJOR(x) ((x >> 16) & 0xff)
+#define SPI_ENGINE_VERSION_MINOR(x) ((x >> 8) & 0xff)
+#define SPI_ENGINE_VERSION_PATCH(x) (x & 0xff)
+
+#define SPI_ENGINE_REG_VERSION 0x00
+
+#define SPI_ENGINE_REG_RESET 0x40
+
+#define SPI_ENGINE_REG_INT_ENABLE 0x80
+#define SPI_ENGINE_REG_INT_PENDING 0x84
+#define SPI_ENGINE_REG_INT_SOURCE 0x88
+
+#define SPI_ENGINE_REG_SYNC_ID 0xc0
+
+#define SPI_ENGINE_REG_CMD_FIFO_ROOM 0xd0
+#define SPI_ENGINE_REG_SDO_FIFO_ROOM 0xd4
+#define SPI_ENGINE_REG_SDI_FIFO_LEVEL 0xd8
+
+#define SPI_ENGINE_REG_CMD_FIFO 0xe0
+#define SPI_ENGINE_REG_SDO_DATA_FIFO 0xe4
+#define SPI_ENGINE_REG_SDI_DATA_FIFO 0xe8
+#define SPI_ENGINE_REG_SDI_DATA_FIFO_PEEK 0xec
+
+#define SPI_ENGINE_INT_CMD_ALMOST_EMPTY BIT(0)
+#define SPI_ENGINE_INT_SDO_ALMOST_EMPTY BIT(1)
+#define SPI_ENGINE_INT_SDI_ALMOST_FULL BIT(2)
+#define SPI_ENGINE_INT_SYNC BIT(3)
+
+#define SPI_ENGINE_CONFIG_CPHA BIT(0)
+#define SPI_ENGINE_CONFIG_CPOL BIT(1)
+#define SPI_ENGINE_CONFIG_3WIRE BIT(2)
+
+#define SPI_ENGINE_INST_TRANSFER 0x0
+#define SPI_ENGINE_INST_ASSERT 0x1
+#define SPI_ENGINE_INST_WRITE 0x2
+#define SPI_ENGINE_INST_MISC 0x3
+
+#define SPI_ENGINE_CMD_REG_CLK_DIV 0x0
+#define SPI_ENGINE_CMD_REG_CONFIG 0x1
+
+#define SPI_ENGINE_MISC_SYNC 0x0
+#define SPI_ENGINE_MISC_SLEEP 0x1
+
+#define SPI_ENGINE_TRANSFER_WRITE 0x1
+#define SPI_ENGINE_TRANSFER_READ 0x2
+
+#define SPI_ENGINE_CMD(inst, arg1, arg2) \
+ (((inst) << 12) | ((arg1) << 8) | (arg2))
+
+#define SPI_ENGINE_CMD_TRANSFER(flags, n) \
+ SPI_ENGINE_CMD(SPI_ENGINE_INST_TRANSFER, (flags), (n))
+#define SPI_ENGINE_CMD_ASSERT(delay, cs) \
+ SPI_ENGINE_CMD(SPI_ENGINE_INST_ASSERT, (delay), (cs))
+#define SPI_ENGINE_CMD_WRITE(reg, val) \
+ SPI_ENGINE_CMD(SPI_ENGINE_INST_WRITE, (reg), (val))
+#define SPI_ENGINE_CMD_SLEEP(delay) \
+ SPI_ENGINE_CMD(SPI_ENGINE_INST_MISC, SPI_ENGINE_MISC_SLEEP, (delay))
+#define SPI_ENGINE_CMD_SYNC(id) \
+ SPI_ENGINE_CMD(SPI_ENGINE_INST_MISC, SPI_ENGINE_MISC_SYNC, (id))
+
+struct spi_engine_program {
+ unsigned int length;
+ uint16_t instructions[];
+};
+
+struct spi_engine {
+ struct clk *clk;
+ struct clk *ref_clk;
+
+ spinlock_t lock;
+
+ void __iomem *base;
+
+ struct spi_message *msg;
+ struct spi_engine_program *p;
+ unsigned cmd_length;
+ const uint16_t *cmd_buf;
+
+ struct spi_transfer *tx_xfer;
+ unsigned int tx_length;
+ const uint8_t *tx_buf;
+
+ struct spi_transfer *rx_xfer;
+ unsigned int rx_length;
+ uint8_t *rx_buf;
+
+ unsigned int sync_id;
+ unsigned int completed_id;
+
+ unsigned int int_enable;
+};
+
+static void spi_engine_program_add_cmd(struct spi_engine_program *p,
+ bool dry, uint16_t cmd)
+{
+ if (!dry)
+ p->instructions[p->length] = cmd;
+ p->length++;
+}
+
+static unsigned int spi_engine_get_config(struct spi_device *spi)
+{
+ unsigned int config = 0;
+
+ if (spi->mode & SPI_CPOL)
+ config |= SPI_ENGINE_CONFIG_CPOL;
+ if (spi->mode & SPI_CPHA)
+ config |= SPI_ENGINE_CONFIG_CPHA;
+ if (spi->mode & SPI_3WIRE)
+ config |= SPI_ENGINE_CONFIG_3WIRE;
+
+ return config;
+}
+
+static unsigned int spi_engine_get_clk_div(struct spi_engine *spi_engine,
+ struct spi_device *spi, struct spi_transfer *xfer)
+{
+ unsigned int clk_div;
+
+ clk_div = DIV_ROUND_UP(clk_get_rate(spi_engine->ref_clk),
+ xfer->speed_hz * 2);
+ if (clk_div > 255)
+ clk_div = 255;
+ else if (clk_div > 0)
+ clk_div -= 1;
+
+ return clk_div;
+}
+
+static void spi_engine_gen_xfer(struct spi_engine_program *p, bool dry,
+ struct spi_transfer *xfer)
+{
+ unsigned int len = xfer->len;
+
+ while (len) {
+ unsigned int n = min(len, 256U);
+ unsigned int flags = 0;
+
+ if (xfer->tx_buf)
+ flags |= SPI_ENGINE_TRANSFER_WRITE;
+ if (xfer->rx_buf)
+ flags |= SPI_ENGINE_TRANSFER_READ;
+
+ spi_engine_program_add_cmd(p, dry,
+ SPI_ENGINE_CMD_TRANSFER(flags, n - 1));
+ len -= n;
+ }
+}
+
+static void spi_engine_gen_sleep(struct spi_engine_program *p, bool dry,
+ struct spi_engine *spi_engine, unsigned int clk_div, unsigned int delay)
+{
+ unsigned int spi_clk = clk_get_rate(spi_engine->ref_clk);
+ unsigned int t;
+
+ if (delay == 0)
+ return;
+
+ t = DIV_ROUND_UP(delay * spi_clk, (clk_div + 1) * 2);
+ while (t) {
+ unsigned int n = min(t, 256U);
+
+ spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_SLEEP(n - 1));
+ t -= n;
+ }
+}
+
+static void spi_engine_gen_cs(struct spi_engine_program *p, bool dry,
+ struct spi_device *spi, bool assert)
+{
+ unsigned int mask = 0xff;
+
+ if (assert)
+ mask ^= BIT(spi->chip_select);
+
+ spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_ASSERT(1, mask));
+}
+
+static int spi_engine_compile_message(struct spi_engine *spi_engine,
+ struct spi_message *msg, bool dry, struct spi_engine_program *p)
+{
+ struct spi_device *spi = msg->spi;
+ struct spi_transfer *xfer;
+ int clk_div, new_clk_div;
+ bool cs_change = true;
+
+ clk_div = -1;
+
+ spi_engine_program_add_cmd(p, dry,
+ SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CONFIG,
+ spi_engine_get_config(spi)));
+
+ list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+ new_clk_div = spi_engine_get_clk_div(spi_engine, spi, xfer);
+ if (new_clk_div != clk_div) {
+ clk_div = new_clk_div;
+ spi_engine_program_add_cmd(p, dry,
+ SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CLK_DIV,
+ clk_div));
+ }
+
+ if (cs_change)
+ spi_engine_gen_cs(p, dry, spi, true);
+
+ spi_engine_gen_xfer(p, dry, xfer);
+ spi_engine_gen_sleep(p, dry, spi_engine, clk_div,
+ xfer->delay_usecs);
+
+ cs_change = xfer->cs_change;
+ if (list_is_last(&xfer->transfer_list, &msg->transfers))
+ cs_change = !cs_change;
+
+ if (cs_change)
+ spi_engine_gen_cs(p, dry, spi, false);
+ }
+
+ return 0;
+}
+
+static void spi_engine_xfer_next(struct spi_engine *spi_engine,
+ struct spi_transfer **_xfer)
+{
+ struct spi_message *msg = spi_engine->msg;
+ struct spi_transfer *xfer = *_xfer;
+
+ if (!xfer) {
+ xfer = list_first_entry(&msg->transfers,
+ struct spi_transfer, transfer_list);
+ } else if (list_is_last(&xfer->transfer_list, &msg->transfers)) {
+ xfer = NULL;
+ } else {
+ xfer = list_next_entry(xfer, transfer_list);
+ }
+
+ *_xfer = xfer;
+}
+
+static void spi_engine_tx_next(struct spi_engine *spi_engine)
+{
+ struct spi_transfer *xfer = spi_engine->tx_xfer;
+
+ do {
+ spi_engine_xfer_next(spi_engine, &xfer);
+ } while (xfer && !xfer->tx_buf);
+
+ spi_engine->tx_xfer = xfer;
+ if (xfer) {
+ spi_engine->tx_length = xfer->len;
+ spi_engine->tx_buf = xfer->tx_buf;
+ } else {
+ spi_engine->tx_buf = NULL;
+ }
+}
+
+static void spi_engine_rx_next(struct spi_engine *spi_engine)
+{
+ struct spi_transfer *xfer = spi_engine->rx_xfer;
+
+ do {
+ spi_engine_xfer_next(spi_engine, &xfer);
+ } while (xfer && !xfer->rx_buf);
+
+ spi_engine->rx_xfer = xfer;
+ if (xfer) {
+ spi_engine->rx_length = xfer->len;
+ spi_engine->rx_buf = xfer->rx_buf;
+ } else {
+ spi_engine->rx_buf = NULL;
+ }
+}
+
+static bool spi_engine_write_cmd_fifo(struct spi_engine *spi_engine)
+{
+ void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_CMD_FIFO;
+ unsigned int n, m, i;
+ const uint16_t *buf;
+
+ n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_CMD_FIFO_ROOM);
+ while (n && spi_engine->cmd_length) {
+ m = min(n, spi_engine->cmd_length);
+ buf = spi_engine->cmd_buf;
+ for (i = 0; i < m; i++)
+ writel_relaxed(buf[i], addr);
+ spi_engine->cmd_buf += m;
+ spi_engine->cmd_length -= m;
+ n -= m;
+ }
+
+ return spi_engine->cmd_length != 0;
+}
+
+static bool spi_engine_write_tx_fifo(struct spi_engine *spi_engine)
+{
+ void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDO_DATA_FIFO;
+ unsigned int n, m, i;
+ const uint8_t *buf;
+
+ n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDO_FIFO_ROOM);
+ while (n && spi_engine->tx_length) {
+ m = min(n, spi_engine->tx_length);
+ buf = spi_engine->tx_buf;
+ for (i = 0; i < m; i++)
+ writel_relaxed(buf[i], addr);
+ spi_engine->tx_buf += m;
+ spi_engine->tx_length -= m;
+ n -= m;
+ if (spi_engine->tx_length == 0)
+ spi_engine_tx_next(spi_engine);
+ }
+
+ return spi_engine->tx_length != 0;
+}
+
+static bool spi_engine_read_rx_fifo(struct spi_engine *spi_engine)
+{
+ void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDI_DATA_FIFO;
+ unsigned int n, m, i;
+ uint8_t *buf;
+
+ n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDI_FIFO_LEVEL);
+ while (n && spi_engine->rx_length) {
+ m = min(n, spi_engine->rx_length);
+ buf = spi_engine->rx_buf;
+ for (i = 0; i < m; i++)
+ buf[i] = readl_relaxed(addr);
+ spi_engine->rx_buf += m;
+ spi_engine->rx_length -= m;
+ n -= m;
+ if (spi_engine->rx_length == 0)
+ spi_engine_rx_next(spi_engine);
+ }
+
+ return spi_engine->rx_length != 0;
+}
+
+static irqreturn_t spi_engine_irq(int irq, void *devid)
+{
+ struct spi_master *master = devid;
+ struct spi_engine *spi_engine = spi_master_get_devdata(master);
+ unsigned int disable_int = 0;
+ unsigned int pending;
+
+ pending = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
+
+ if (pending & SPI_ENGINE_INT_SYNC) {
+ writel_relaxed(SPI_ENGINE_INT_SYNC,
+ spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
+ spi_engine->completed_id = readl_relaxed(
+ spi_engine->base + SPI_ENGINE_REG_SYNC_ID);
+ }
+
+ spin_lock(&spi_engine->lock);
+
+ if (pending & SPI_ENGINE_INT_CMD_ALMOST_EMPTY) {
+ if (!spi_engine_write_cmd_fifo(spi_engine))
+ disable_int |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY;
+ }
+
+ if (pending & SPI_ENGINE_INT_SDO_ALMOST_EMPTY) {
+ if (!spi_engine_write_tx_fifo(spi_engine))
+ disable_int |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY;
+ }
+
+ if (pending & (SPI_ENGINE_INT_SDI_ALMOST_FULL | SPI_ENGINE_INT_SYNC)) {
+ if (!spi_engine_read_rx_fifo(spi_engine))
+ disable_int |= SPI_ENGINE_INT_SDI_ALMOST_FULL;
+ }
+
+ if (pending & SPI_ENGINE_INT_SYNC) {
+ if (spi_engine->msg &&
+ spi_engine->completed_id == spi_engine->sync_id) {
+ struct spi_message *msg = spi_engine->msg;
+
+ kfree(spi_engine->p);
+ msg->status = 0;
+ msg->actual_length = msg->frame_length;
+ spi_engine->msg = NULL;
+ spi_finalize_current_message(master);
+ disable_int |= SPI_ENGINE_INT_SYNC;
+ }
+ }
+
+ if (disable_int) {
+ spi_engine->int_enable &= ~disable_int;
+ writel_relaxed(spi_engine->int_enable,
+ spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
+ }
+
+ spin_unlock(&spi_engine->lock);
+
+ return IRQ_HANDLED;
+}
+
+static int spi_engine_transfer_one_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct spi_engine_program p_dry, *p;
+ struct spi_engine *spi_engine = spi_master_get_devdata(master);
+ unsigned int int_enable = 0;
+ unsigned long flags;
+ size_t size;
+
+ p_dry.length = 0;
+ spi_engine_compile_message(spi_engine, msg, true, &p_dry);
+
+ size = sizeof(*p->instructions) * (p_dry.length + 1);
+ p = kzalloc(sizeof(*p) + size, GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+ spi_engine_compile_message(spi_engine, msg, false, p);
+
+ spin_lock_irqsave(&spi_engine->lock, flags);
+ spi_engine->sync_id = (spi_engine->sync_id + 1) & 0xff;
+ spi_engine_program_add_cmd(p, false,
+ SPI_ENGINE_CMD_SYNC(spi_engine->sync_id));
+
+ spi_engine->msg = msg;
+ spi_engine->p = p;
+
+ spi_engine->cmd_buf = p->instructions;
+ spi_engine->cmd_length = p->length;
+ if (spi_engine_write_cmd_fifo(spi_engine))
+ int_enable |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY;
+
+ spi_engine_tx_next(spi_engine);
+ if (spi_engine_write_tx_fifo(spi_engine))
+ int_enable |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY;
+
+ spi_engine_rx_next(spi_engine);
+ if (spi_engine->rx_length != 0)
+ int_enable |= SPI_ENGINE_INT_SDI_ALMOST_FULL;
+
+ int_enable |= SPI_ENGINE_INT_SYNC;
+
+ writel_relaxed(int_enable,
+ spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
+ spi_engine->int_enable = int_enable;
+ spin_unlock_irqrestore(&spi_engine->lock, flags);
+
+ return 0;
+}
+
+static int spi_engine_probe(struct platform_device *pdev)
+{
+ struct spi_engine *spi_engine;
+ struct spi_master *master;
+ unsigned int version;
+ struct resource *res;
+ int irq;
+ int ret;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq <= 0)
+ return -ENXIO;
+
+ spi_engine = devm_kzalloc(&pdev->dev, sizeof(*spi_engine), GFP_KERNEL);
+ if (!spi_engine)
+ return -ENOMEM;
+
+ master = spi_alloc_master(&pdev->dev, 0);
+ if (!master)
+ return -ENOMEM;
+
+ spi_master_set_devdata(master, spi_engine);
+
+ spin_lock_init(&spi_engine->lock);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ spi_engine->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(spi_engine->base)) {
+ ret = PTR_ERR(spi_engine->base);
+ goto err_put_master;
+ }
+
+ version = readl(spi_engine->base + SPI_ENGINE_REG_VERSION);
+ if (SPI_ENGINE_VERSION_MAJOR(version) != 1) {
+ dev_err(&pdev->dev, "Unsupported peripheral version %u.%u.%c\n",
+ SPI_ENGINE_VERSION_MAJOR(version),
+ SPI_ENGINE_VERSION_MINOR(version),
+ SPI_ENGINE_VERSION_PATCH(version));
+ return -ENODEV;
+ }
+
+ spi_engine->clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
+ if (IS_ERR(spi_engine->clk)) {
+ ret = PTR_ERR(spi_engine->clk);
+ goto err_put_master;
+ }
+
+ spi_engine->ref_clk = devm_clk_get(&pdev->dev, "spi_clk");
+ if (IS_ERR(spi_engine->ref_clk)) {
+ ret = PTR_ERR(spi_engine->ref_clk);
+ goto err_put_master;
+ }
+
+ ret = clk_prepare_enable(spi_engine->clk);
+ if (ret)
+ goto err_put_master;
+
+ ret = clk_prepare_enable(spi_engine->ref_clk);
+ if (ret)
+ goto err_clk_disable;
+
+ writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_RESET);
+ writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
+ writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
+
+ ret = request_irq(irq, spi_engine_irq, 0, pdev->name, master);
+ if (ret)
+ goto err_ref_clk_disable;
+
+ master->dev.parent = &pdev->dev;
+ master->dev.of_node = pdev->dev.of_node;
+ master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_3WIRE;
+ master->bits_per_word_mask = SPI_BPW_MASK(8);
+ master->max_speed_hz = clk_get_rate(spi_engine->ref_clk) / 2;
+ master->transfer_one_message = spi_engine_transfer_one_message;
+ master->num_chipselect = 8;
+
+ ret = spi_register_master(master);
+ if (ret)
+ goto err_free_irq;
+
+ platform_set_drvdata(pdev, master);
+
+ return 0;
+err_free_irq:
+ free_irq(irq, master);
+err_ref_clk_disable:
+ clk_disable_unprepare(spi_engine->ref_clk);
+err_clk_disable:
+ clk_disable_unprepare(spi_engine->clk);
+err_put_master:
+ spi_master_put(master);
+ return ret;
+}
+
+static int spi_engine_remove(struct platform_device *pdev)
+{
+ struct spi_master *master = platform_get_drvdata(pdev);
+ struct spi_engine *spi_engine = spi_master_get_devdata(master);
+ int irq = platform_get_irq(pdev, 0);
+
+ spi_unregister_master(master);
+
+ free_irq(irq, master);
+
+ writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
+ writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
+ writel_relaxed(0x01, spi_engine->base + SPI_ENGINE_REG_RESET);
+
+ clk_disable_unprepare(spi_engine->ref_clk);
+ clk_disable_unprepare(spi_engine->clk);
+
+ return 0;
+}
+
+static const struct of_device_id spi_engine_match_table[] = {
+ { .compatible = "adi,axi-spi-engine-1.00.a" },
+ { },
+};
+
+static struct platform_driver spi_engine_driver = {
+ .probe = spi_engine_probe,
+ .remove = spi_engine_remove,
+ .driver = {
+ .name = "spi-engine",
+ .of_match_table = spi_engine_match_table,
+ },
+};
+module_platform_driver(spi_engine_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("Analog Devices SPI engine peripheral driver");
+MODULE_LICENSE("GPL");
projects / karo-tx-linux.git / commitdiff