Initial import

1 files changed, 623 insertions, 0 deletions

diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
new file mode 100644
index 000000000..8d67d03c7
--- /dev/null
+++ b/drivers/spi/spi-dw.c
@@ -0,0 +1,623 @@
+/*
+ * Designware SPI core controller driver (refer pxa2xx_spi.c)
+ *
+ * Copyright (c) 2009, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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 <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/highmem.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+#include <linux/gpio.h>
+
+#include "spi-dw.h"
+
+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+#endif
+
+/* Slave spi_dev related */
+struct chip_data {
+	u16 cr0;
+	u8 cs;			/* chip select pin */
+	u8 n_bytes;		/* current is a 1/2/4 byte op */
+	u8 tmode;		/* TR/TO/RO/EEPROM */
+	u8 type;		/* SPI/SSP/MicroWire */
+
+	u8 poll_mode;		/* 1 means use poll mode */
+
+	u32 dma_width;
+	u32 rx_threshold;
+	u32 tx_threshold;
+	u8 enable_dma;
+	u8 bits_per_word;
+	u16 clk_div;		/* baud rate divider */
+	u32 speed_hz;		/* baud rate */
+	void (*cs_control)(u32 command);
+};
+
+#ifdef CONFIG_DEBUG_FS
+#define SPI_REGS_BUFSIZE	1024
+static ssize_t dw_spi_show_regs(struct file *file, char __user *user_buf,
+		size_t count, loff_t *ppos)
+{
+	struct dw_spi *dws = file->private_data;
+	char *buf;
+	u32 len = 0;
+	ssize_t ret;
+
+	buf = kzalloc(SPI_REGS_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return 0;
+
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"%s registers:\n", dev_name(&dws->master->dev));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"=================================\n");
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"CTRL0: \t\t0x%08x\n", dw_readl(dws, DW_SPI_CTRL0));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"CTRL1: \t\t0x%08x\n", dw_readl(dws, DW_SPI_CTRL1));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"SSIENR: \t0x%08x\n", dw_readl(dws, DW_SPI_SSIENR));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"SER: \t\t0x%08x\n", dw_readl(dws, DW_SPI_SER));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"BAUDR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_BAUDR));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"TXFTLR: \t0x%08x\n", dw_readl(dws, DW_SPI_TXFLTR));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"RXFTLR: \t0x%08x\n", dw_readl(dws, DW_SPI_RXFLTR));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"TXFLR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_TXFLR));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"RXFLR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_RXFLR));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"SR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_SR));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"IMR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_IMR));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"ISR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_ISR));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"DMACR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_DMACR));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"DMATDLR: \t0x%08x\n", dw_readl(dws, DW_SPI_DMATDLR));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"DMARDLR: \t0x%08x\n", dw_readl(dws, DW_SPI_DMARDLR));
+	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+			"=================================\n");
+
+	ret = simple_read_from_buffer(user_buf, count, ppos, buf, len);
+	kfree(buf);
+	return ret;
+}
+
+static const struct file_operations dw_spi_regs_ops = {
+	.owner		= THIS_MODULE,
+	.open		= simple_open,
+	.read		= dw_spi_show_regs,
+	.llseek		= default_llseek,
+};
+
+static int dw_spi_debugfs_init(struct dw_spi *dws)
+{
+	dws->debugfs = debugfs_create_dir("dw_spi", NULL);
+	if (!dws->debugfs)
+		return -ENOMEM;
+
+	debugfs_create_file("registers", S_IFREG | S_IRUGO,
+		dws->debugfs, (void *)dws, &dw_spi_regs_ops);
+	return 0;
+}
+
+static void dw_spi_debugfs_remove(struct dw_spi *dws)
+{
+	debugfs_remove_recursive(dws->debugfs);
+}
+
+#else
+static inline int dw_spi_debugfs_init(struct dw_spi *dws)
+{
+	return 0;
+}
+
+static inline void dw_spi_debugfs_remove(struct dw_spi *dws)
+{
+}
+#endif /* CONFIG_DEBUG_FS */
+
+static void dw_spi_set_cs(struct spi_device *spi, bool enable)
+{
+	struct dw_spi *dws = spi_master_get_devdata(spi->master);
+	struct chip_data *chip = spi_get_ctldata(spi);
+
+	/* Chip select logic is inverted from spi_set_cs() */
+	if (chip && chip->cs_control)
+		chip->cs_control(!enable);
+
+	if (!enable)
+		dw_writel(dws, DW_SPI_SER, BIT(spi->chip_select));
+}
+
+/* Return the max entries we can fill into tx fifo */
+static inline u32 tx_max(struct dw_spi *dws)
+{
+	u32 tx_left, tx_room, rxtx_gap;
+
+	tx_left = (dws->tx_end - dws->tx) / dws->n_bytes;
+	tx_room = dws->fifo_len - dw_readl(dws, DW_SPI_TXFLR);
+
+	/*
+	 * Another concern is about the tx/rx mismatch, we
+	 * though to use (dws->fifo_len - rxflr - txflr) as
+	 * one maximum value for tx, but it doesn't cover the
+	 * data which is out of tx/rx fifo and inside the
+	 * shift registers. So a control from sw point of
+	 * view is taken.
+	 */
+	rxtx_gap =  ((dws->rx_end - dws->rx) - (dws->tx_end - dws->tx))
+			/ dws->n_bytes;
+
+	return min3(tx_left, tx_room, (u32) (dws->fifo_len - rxtx_gap));
+}
+
+/* Return the max entries we should read out of rx fifo */
+static inline u32 rx_max(struct dw_spi *dws)
+{
+	u32 rx_left = (dws->rx_end - dws->rx) / dws->n_bytes;
+
+	return min_t(u32, rx_left, dw_readl(dws, DW_SPI_RXFLR));
+}
+
+static void dw_writer(struct dw_spi *dws)
+{
+	u32 max = tx_max(dws);
+	u16 txw = 0;
+
+	while (max--) {
+		/* Set the tx word if the transfer's original "tx" is not null */
+		if (dws->tx_end - dws->len) {
+			if (dws->n_bytes == 1)
+				txw = *(u8 *)(dws->tx);
+			else
+				txw = *(u16 *)(dws->tx);
+		}
+		dw_writel(dws, DW_SPI_DR, txw);
+		dws->tx += dws->n_bytes;
+	}
+}
+
+static void dw_reader(struct dw_spi *dws)
+{
+	u32 max = rx_max(dws);
+	u16 rxw;
+
+	while (max--) {
+		rxw = dw_readl(dws, DW_SPI_DR);
+		/* Care rx only if the transfer's original "rx" is not null */
+		if (dws->rx_end - dws->len) {
+			if (dws->n_bytes == 1)
+				*(u8 *)(dws->rx) = rxw;
+			else
+				*(u16 *)(dws->rx) = rxw;
+		}
+		dws->rx += dws->n_bytes;
+	}
+}
+
+static void int_error_stop(struct dw_spi *dws, const char *msg)
+{
+	spi_reset_chip(dws);
+
+	dev_err(&dws->master->dev, "%s\n", msg);
+	dws->master->cur_msg->status = -EIO;
+	spi_finalize_current_transfer(dws->master);
+}
+
+static irqreturn_t interrupt_transfer(struct dw_spi *dws)
+{
+	u16 irq_status = dw_readl(dws, DW_SPI_ISR);
+
+	/* Error handling */
+	if (irq_status & (SPI_INT_TXOI | SPI_INT_RXOI | SPI_INT_RXUI)) {
+		dw_readl(dws, DW_SPI_ICR);
+		int_error_stop(dws, "interrupt_transfer: fifo overrun/underrun");
+		return IRQ_HANDLED;
+	}
+
+	dw_reader(dws);
+	if (dws->rx_end == dws->rx) {
+		spi_mask_intr(dws, SPI_INT_TXEI);
+		spi_finalize_current_transfer(dws->master);
+		return IRQ_HANDLED;
+	}
+	if (irq_status & SPI_INT_TXEI) {
+		spi_mask_intr(dws, SPI_INT_TXEI);
+		dw_writer(dws);
+		/* Enable TX irq always, it will be disabled when RX finished */
+		spi_umask_intr(dws, SPI_INT_TXEI);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t dw_spi_irq(int irq, void *dev_id)
+{
+	struct spi_master *master = dev_id;
+	struct dw_spi *dws = spi_master_get_devdata(master);
+	u16 irq_status = dw_readl(dws, DW_SPI_ISR) & 0x3f;
+
+	if (!irq_status)
+		return IRQ_NONE;
+
+	if (!master->cur_msg) {
+		spi_mask_intr(dws, SPI_INT_TXEI);
+		return IRQ_HANDLED;
+	}
+
+	return dws->transfer_handler(dws);
+}
+
+/* Must be called inside pump_transfers() */
+static int poll_transfer(struct dw_spi *dws)
+{
+	do {
+		dw_writer(dws);
+		dw_reader(dws);
+		cpu_relax();
+	} while (dws->rx_end > dws->rx);
+
+	return 0;
+}
+
+static int dw_spi_transfer_one(struct spi_master *master,
+		struct spi_device *spi, struct spi_transfer *transfer)
+{
+	struct dw_spi *dws = spi_master_get_devdata(master);
+	struct chip_data *chip = spi_get_ctldata(spi);
+	u8 imask = 0;
+	u16 txlevel = 0;
+	u16 clk_div = 0;
+	u32 speed = 0;
+	u32 cr0 = 0;
+	int ret;
+
+	dws->dma_mapped = 0;
+	dws->n_bytes = chip->n_bytes;
+	dws->dma_width = chip->dma_width;
+
+	dws->tx = (void *)transfer->tx_buf;
+	dws->tx_end = dws->tx + transfer->len;
+	dws->rx = transfer->rx_buf;
+	dws->rx_end = dws->rx + transfer->len;
+	dws->len = transfer->len;
+
+	spi_enable_chip(dws, 0);
+
+	cr0 = chip->cr0;
+
+	/* Handle per transfer options for bpw and speed */
+	if (transfer->speed_hz) {
+		speed = chip->speed_hz;
+
+		if ((transfer->speed_hz != speed) || !chip->clk_div) {
+			speed = transfer->speed_hz;
+
+			/* clk_div doesn't support odd number */
+			clk_div = (dws->max_freq / speed + 1) & 0xfffe;
+
+			chip->speed_hz = speed;
+			chip->clk_div = clk_div;
+
+			spi_set_clk(dws, chip->clk_div);
+		}
+	}
+	if (transfer->bits_per_word) {
+		if (transfer->bits_per_word == 8) {
+			dws->n_bytes = 1;
+			dws->dma_width = 1;
+		} else if (transfer->bits_per_word == 16) {
+			dws->n_bytes = 2;
+			dws->dma_width = 2;
+		}
+		cr0 = (transfer->bits_per_word - 1)
+			| (chip->type << SPI_FRF_OFFSET)
+			| (spi->mode << SPI_MODE_OFFSET)
+			| (chip->tmode << SPI_TMOD_OFFSET);
+	}
+
+	/*
+	 * Adjust transfer mode if necessary. Requires platform dependent
+	 * chipselect mechanism.
+	 */
+	if (chip->cs_control) {
+		if (dws->rx && dws->tx)
+			chip->tmode = SPI_TMOD_TR;
+		else if (dws->rx)
+			chip->tmode = SPI_TMOD_RO;
+		else
+			chip->tmode = SPI_TMOD_TO;
+
+		cr0 &= ~SPI_TMOD_MASK;
+		cr0 |= (chip->tmode << SPI_TMOD_OFFSET);
+	}
+
+	dw_writel(dws, DW_SPI_CTRL0, cr0);
+
+	/* Check if current transfer is a DMA transaction */
+	if (master->can_dma && master->can_dma(master, spi, transfer))
+		dws->dma_mapped = master->cur_msg_mapped;
+
+	/* For poll mode just disable all interrupts */
+	spi_mask_intr(dws, 0xff);
+
+	/*
+	 * Interrupt mode
+	 * we only need set the TXEI IRQ, as TX/RX always happen syncronizely
+	 */
+	if (dws->dma_mapped) {
+		ret = dws->dma_ops->dma_setup(dws, transfer);
+		if (ret < 0) {
+			spi_enable_chip(dws, 1);
+			return ret;
+		}
+	} else if (!chip->poll_mode) {
+		txlevel = min_t(u16, dws->fifo_len / 2, dws->len / dws->n_bytes);
+		dw_writel(dws, DW_SPI_TXFLTR, txlevel);
+
+		/* Set the interrupt mask */
+		imask |= SPI_INT_TXEI | SPI_INT_TXOI |
+			 SPI_INT_RXUI | SPI_INT_RXOI;
+		spi_umask_intr(dws, imask);
+
+		dws->transfer_handler = interrupt_transfer;
+	}
+
+	spi_enable_chip(dws, 1);
+
+	if (dws->dma_mapped) {
+		ret = dws->dma_ops->dma_transfer(dws, transfer);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (chip->poll_mode)
+		return poll_transfer(dws);
+
+	return 1;
+}
+
+static void dw_spi_handle_err(struct spi_master *master,
+		struct spi_message *msg)
+{
+	struct dw_spi *dws = spi_master_get_devdata(master);
+
+	if (dws->dma_mapped)
+		dws->dma_ops->dma_stop(dws);
+
+	spi_reset_chip(dws);
+}
+
+/* This may be called twice for each spi dev */
+static int dw_spi_setup(struct spi_device *spi)
+{
+	struct dw_spi_chip *chip_info = NULL;
+	struct chip_data *chip;
+	int ret;
+
+	/* Only alloc on first setup */
+	chip = spi_get_ctldata(spi);
+	if (!chip) {
+		chip = kzalloc(sizeof(struct chip_data), GFP_KERNEL);
+		if (!chip)
+			return -ENOMEM;
+		spi_set_ctldata(spi, chip);
+	}
+
+	/*
+	 * Protocol drivers may change the chip settings, so...
+	 * if chip_info exists, use it
+	 */
+	chip_info = spi->controller_data;
+
+	/* chip_info doesn't always exist */
+	if (chip_info) {
+		if (chip_info->cs_control)
+			chip->cs_control = chip_info->cs_control;
+
+		chip->poll_mode = chip_info->poll_mode;
+		chip->type = chip_info->type;
+
+		chip->rx_threshold = 0;
+		chip->tx_threshold = 0;
+	}
+
+	if (spi->bits_per_word == 8) {
+		chip->n_bytes = 1;
+		chip->dma_width = 1;
+	} else if (spi->bits_per_word == 16) {
+		chip->n_bytes = 2;
+		chip->dma_width = 2;
+	}
+	chip->bits_per_word = spi->bits_per_word;
+
+	if (!spi->max_speed_hz) {
+		dev_err(&spi->dev, "No max speed HZ parameter\n");
+		return -EINVAL;
+	}
+
+	chip->tmode = 0; /* Tx & Rx */
+	/* Default SPI mode is SCPOL = 0, SCPH = 0 */
+	chip->cr0 = (chip->bits_per_word - 1)
+			| (chip->type << SPI_FRF_OFFSET)
+			| (spi->mode  << SPI_MODE_OFFSET)
+			| (chip->tmode << SPI_TMOD_OFFSET);
+
+	if (spi->mode & SPI_LOOP)
+		chip->cr0 |= 1 << SPI_SRL_OFFSET;
+
+	if (gpio_is_valid(spi->cs_gpio)) {
+		ret = gpio_direction_output(spi->cs_gpio,
+				!(spi->mode & SPI_CS_HIGH));
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static void dw_spi_cleanup(struct spi_device *spi)
+{
+	struct chip_data *chip = spi_get_ctldata(spi);
+
+	kfree(chip);
+	spi_set_ctldata(spi, NULL);
+}
+
+/* Restart the controller, disable all interrupts, clean rx fifo */
+static void spi_hw_init(struct device *dev, struct dw_spi *dws)
+{
+	spi_reset_chip(dws);
+
+	/*
+	 * Try to detect the FIFO depth if not set by interface driver,
+	 * the depth could be from 2 to 256 from HW spec
+	 */
+	if (!dws->fifo_len) {
+		u32 fifo;
+
+		for (fifo = 1; fifo < 256; fifo++) {
+			dw_writel(dws, DW_SPI_TXFLTR, fifo);
+			if (fifo != dw_readl(dws, DW_SPI_TXFLTR))
+				break;
+		}
+		dw_writel(dws, DW_SPI_TXFLTR, 0);
+
+		dws->fifo_len = (fifo == 1) ? 0 : fifo;
+		dev_dbg(dev, "Detected FIFO size: %u bytes\n", dws->fifo_len);
+	}
+}
+
+int dw_spi_add_host(struct device *dev, struct dw_spi *dws)
+{
+	struct spi_master *master;
+	int ret;
+
+	BUG_ON(dws == NULL);
+
+	master = spi_alloc_master(dev, 0);
+	if (!master)
+		return -ENOMEM;
+
+	dws->master = master;
+	dws->type = SSI_MOTO_SPI;
+	dws->dma_inited = 0;
+	dws->dma_addr = (dma_addr_t)(dws->paddr + 0x60);
+	snprintf(dws->name, sizeof(dws->name), "dw_spi%d", dws->bus_num);
+
+	ret = devm_request_irq(dev, dws->irq, dw_spi_irq, IRQF_SHARED,
+			dws->name, master);
+	if (ret < 0) {
+		dev_err(&master->dev, "can not get IRQ\n");
+		goto err_free_master;
+	}
+
+	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP;
+	master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
+	master->bus_num = dws->bus_num;
+	master->num_chipselect = dws->num_cs;
+	master->setup = dw_spi_setup;
+	master->cleanup = dw_spi_cleanup;
+	master->set_cs = dw_spi_set_cs;
+	master->transfer_one = dw_spi_transfer_one;
+	master->handle_err = dw_spi_handle_err;
+	master->max_speed_hz = dws->max_freq;
+	master->dev.of_node = dev->of_node;
+
+	/* Basic HW init */
+	spi_hw_init(dev, dws);
+
+	if (dws->dma_ops && dws->dma_ops->dma_init) {
+		ret = dws->dma_ops->dma_init(dws);
+		if (ret) {
+			dev_warn(dev, "DMA init failed\n");
+			dws->dma_inited = 0;
+		} else {
+			master->can_dma = dws->dma_ops->can_dma;
+		}
+	}
+
+	spi_master_set_devdata(master, dws);
+	ret = devm_spi_register_master(dev, master);
+	if (ret) {
+		dev_err(&master->dev, "problem registering spi master\n");
+		goto err_dma_exit;
+	}
+
+	dw_spi_debugfs_init(dws);
+	return 0;
+
+err_dma_exit:
+	if (dws->dma_ops && dws->dma_ops->dma_exit)
+		dws->dma_ops->dma_exit(dws);
+	spi_enable_chip(dws, 0);
+err_free_master:
+	spi_master_put(master);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dw_spi_add_host);
+
+void dw_spi_remove_host(struct dw_spi *dws)
+{
+	if (!dws)
+		return;
+	dw_spi_debugfs_remove(dws);
+
+	if (dws->dma_ops && dws->dma_ops->dma_exit)
+		dws->dma_ops->dma_exit(dws);
+	spi_enable_chip(dws, 0);
+	/* Disable clk */
+	spi_set_clk(dws, 0);
+}
+EXPORT_SYMBOL_GPL(dw_spi_remove_host);
+
+int dw_spi_suspend_host(struct dw_spi *dws)
+{
+	int ret = 0;
+
+	ret = spi_master_suspend(dws->master);
+	if (ret)
+		return ret;
+	spi_enable_chip(dws, 0);
+	spi_set_clk(dws, 0);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dw_spi_suspend_host);
+
+int dw_spi_resume_host(struct dw_spi *dws)
+{
+	int ret;
+
+	spi_hw_init(&dws->master->dev, dws);
+	ret = spi_master_resume(dws->master);
+	if (ret)
+		dev_err(&dws->master->dev, "fail to start queue (%d)\n", ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dw_spi_resume_host);
+
+MODULE_AUTHOR("Feng Tang <feng.tang@intel.com>");
+MODULE_DESCRIPTION("Driver for DesignWare SPI controller core");
+MODULE_LICENSE("GPL v2");