--- /dev/null
+/*
+ * Xilinx SPI controller driver (master mode only)
+ *
+ * Author: MontaVista Software, Inc.
+ * source@mvista.com
+ *
+ * Copyright (c) 2010 Secret Lab Technologies, Ltd.
+ * Copyright (c) 2009 Intel Corporation
+ * 2002-2007 (c) MontaVista Software, Inc.
+
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/spi/xilinx_spi.h>
+#include <linux/io.h>
+
+#define XILINX_SPI_MAX_CS 32
+
+#define XILINX_SPI_NAME "xilinx_spi"
+
+/* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e)
+ * Product Specification", DS464
+ */
+#define XSPI_CR_OFFSET 0x60 /* Control Register */
+
+#define XSPI_CR_LOOP 0x01
+#define XSPI_CR_ENABLE 0x02
+#define XSPI_CR_MASTER_MODE 0x04
+#define XSPI_CR_CPOL 0x08
+#define XSPI_CR_CPHA 0x10
+#define XSPI_CR_MODE_MASK (XSPI_CR_CPHA | XSPI_CR_CPOL | \
+ XSPI_CR_LSB_FIRST | XSPI_CR_LOOP)
+#define XSPI_CR_TXFIFO_RESET 0x20
+#define XSPI_CR_RXFIFO_RESET 0x40
+#define XSPI_CR_MANUAL_SSELECT 0x80
+#define XSPI_CR_TRANS_INHIBIT 0x100
+#define XSPI_CR_LSB_FIRST 0x200
+
+#define XSPI_SR_OFFSET 0x64 /* Status Register */
+
+#define XSPI_SR_RX_EMPTY_MASK 0x01 /* Receive FIFO is empty */
+#define XSPI_SR_RX_FULL_MASK 0x02 /* Receive FIFO is full */
+#define XSPI_SR_TX_EMPTY_MASK 0x04 /* Transmit FIFO is empty */
+#define XSPI_SR_TX_FULL_MASK 0x08 /* Transmit FIFO is full */
+#define XSPI_SR_MODE_FAULT_MASK 0x10 /* Mode fault error */
+
+#define XSPI_TXD_OFFSET 0x68 /* Data Transmit Register */
+#define XSPI_RXD_OFFSET 0x6c /* Data Receive Register */
+
+#define XSPI_SSR_OFFSET 0x70 /* 32-bit Slave Select Register */
+
+/* Register definitions as per "OPB IPIF (v3.01c) Product Specification", DS414
+ * IPIF registers are 32 bit
+ */
+#define XIPIF_V123B_DGIER_OFFSET 0x1c /* IPIF global int enable reg */
+#define XIPIF_V123B_GINTR_ENABLE 0x80000000
+
+#define XIPIF_V123B_IISR_OFFSET 0x20 /* IPIF interrupt status reg */
+#define XIPIF_V123B_IIER_OFFSET 0x28 /* IPIF interrupt enable reg */
+
+#define XSPI_INTR_MODE_FAULT 0x01 /* Mode fault error */
+#define XSPI_INTR_SLAVE_MODE_FAULT 0x02 /* Selected as slave while
+ * disabled */
+#define XSPI_INTR_TX_EMPTY 0x04 /* TxFIFO is empty */
+#define XSPI_INTR_TX_UNDERRUN 0x08 /* TxFIFO was underrun */
+#define XSPI_INTR_RX_FULL 0x10 /* RxFIFO is full */
+#define XSPI_INTR_RX_OVERRUN 0x20 /* RxFIFO was overrun */
+#define XSPI_INTR_TX_HALF_EMPTY 0x40 /* TxFIFO is half empty */
+
+#define XIPIF_V123B_RESETR_OFFSET 0x40 /* IPIF reset register */
+#define XIPIF_V123B_RESET_MASK 0x0a /* the value to write */
+
+struct xilinx_spi {
+ /* bitbang has to be first */
+ struct spi_bitbang bitbang;
+ struct completion done;
+ void __iomem *regs; /* virt. address of the control registers */
+
+ int irq;
+
+ u8 *rx_ptr; /* pointer in the Tx buffer */
+ const u8 *tx_ptr; /* pointer in the Rx buffer */
+ u8 bytes_per_word;
+ int buffer_size; /* buffer size in words */
+ u32 cs_inactive; /* Level of the CS pins when inactive*/
+ unsigned int (*read_fn)(void __iomem *);
+ void (*write_fn)(u32, void __iomem *);
+};
+
+static void xspi_write32(u32 val, void __iomem *addr)
+{
+ iowrite32(val, addr);
+}
+
+static unsigned int xspi_read32(void __iomem *addr)
+{
+ return ioread32(addr);
+}
+
+static void xspi_write32_be(u32 val, void __iomem *addr)
+{
+ iowrite32be(val, addr);
+}
+
+static unsigned int xspi_read32_be(void __iomem *addr)
+{
+ return ioread32be(addr);
+}
+
+static void xilinx_spi_tx(struct xilinx_spi *xspi)
+{
+ u32 data = 0;
+
+ if (!xspi->tx_ptr) {
+ xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
+ return;
+ }
+
+ switch (xspi->bytes_per_word) {
+ case 1:
+ data = *(u8 *)(xspi->tx_ptr);
+ break;
+ case 2:
+ data = *(u16 *)(xspi->tx_ptr);
+ break;
+ case 4:
+ data = *(u32 *)(xspi->tx_ptr);
+ break;
+ }
+
+ xspi->write_fn(data, xspi->regs + XSPI_TXD_OFFSET);
+ xspi->tx_ptr += xspi->bytes_per_word;
+}
+
+static void xilinx_spi_rx(struct xilinx_spi *xspi)
+{
+ u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
+
+ if (!xspi->rx_ptr)
+ return;
+
+ switch (xspi->bytes_per_word) {
+ case 1:
+ *(u8 *)(xspi->rx_ptr) = data;
+ break;
+ case 2:
+ *(u16 *)(xspi->rx_ptr) = data;
+ break;
+ case 4:
+ *(u32 *)(xspi->rx_ptr) = data;
+ break;
+ }
+
+ xspi->rx_ptr += xspi->bytes_per_word;
+}
+
+static void xspi_init_hw(struct xilinx_spi *xspi)
+{
+ void __iomem *regs_base = xspi->regs;
+
+ /* Reset the SPI device */
+ xspi->write_fn(XIPIF_V123B_RESET_MASK,
+ regs_base + XIPIF_V123B_RESETR_OFFSET);
+ /* Enable the transmit empty interrupt, which we use to determine
+ * progress on the transmission.
+ */
+ xspi->write_fn(XSPI_INTR_TX_EMPTY,
+ regs_base + XIPIF_V123B_IIER_OFFSET);
+ /* Disable the global IPIF interrupt */
+ xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET);
+ /* Deselect the slave on the SPI bus */
+ xspi->write_fn(0xffff, regs_base + XSPI_SSR_OFFSET);
+ /* Disable the transmitter, enable Manual Slave Select Assertion,
+ * put SPI controller into master mode, and enable it */
+ xspi->write_fn(XSPI_CR_MANUAL_SSELECT | XSPI_CR_MASTER_MODE |
+ XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET | XSPI_CR_RXFIFO_RESET,
+ regs_base + XSPI_CR_OFFSET);
+}
+
+static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
+{
+ struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
+ u16 cr;
+ u32 cs;
+
+ if (is_on == BITBANG_CS_INACTIVE) {
+ /* Deselect the slave on the SPI bus */
+ xspi->write_fn(xspi->cs_inactive, xspi->regs + XSPI_SSR_OFFSET);
+ return;
+ }
+
+ /* Set the SPI clock phase and polarity */
+ cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) & ~XSPI_CR_MODE_MASK;
+ if (spi->mode & SPI_CPHA)
+ cr |= XSPI_CR_CPHA;
+ if (spi->mode & SPI_CPOL)
+ cr |= XSPI_CR_CPOL;
+ if (spi->mode & SPI_LSB_FIRST)
+ cr |= XSPI_CR_LSB_FIRST;
+ if (spi->mode & SPI_LOOP)
+ cr |= XSPI_CR_LOOP;
+ xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
+
+ /* We do not check spi->max_speed_hz here as the SPI clock
+ * frequency is not software programmable (the IP block design
+ * parameter)
+ */
+
+ cs = xspi->cs_inactive;
+ cs ^= BIT(spi->chip_select);
+
+ /* Activate the chip select */
+ xspi->write_fn(cs, xspi->regs + XSPI_SSR_OFFSET);
+}
+
+/* spi_bitbang requires custom setup_transfer() to be defined if there is a
+ * custom txrx_bufs().
+ */
+static int xilinx_spi_setup_transfer(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
+
+ if (spi->mode & SPI_CS_HIGH)
+ xspi->cs_inactive &= ~BIT(spi->chip_select);
+ else
+ xspi->cs_inactive |= BIT(spi->chip_select);
+
+ return 0;
+}
+
+static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
+{
+ struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
+ int remaining_words; /* the number of words left to transfer */
+ bool use_irq = false;
+ u16 cr = 0;
+
+ /* We get here with transmitter inhibited */
+
+ xspi->tx_ptr = t->tx_buf;
+ xspi->rx_ptr = t->rx_buf;
+ remaining_words = t->len / xspi->bytes_per_word;
+ reinit_completion(&xspi->done);
+
+ if (xspi->irq >= 0 && remaining_words > xspi->buffer_size) {
+ use_irq = true;
+ xspi->write_fn(XSPI_INTR_TX_EMPTY,
+ xspi->regs + XIPIF_V123B_IISR_OFFSET);
+ /* Enable the global IPIF interrupt */
+ xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
+ xspi->regs + XIPIF_V123B_DGIER_OFFSET);
+ /* Inhibit irq to avoid spurious irqs on tx_empty*/
+ cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
+ xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
+ xspi->regs + XSPI_CR_OFFSET);
+ }
+
+ while (remaining_words) {
+ int n_words, tx_words, rx_words;
+
+ n_words = min(remaining_words, xspi->buffer_size);
+
+ tx_words = n_words;
+ while (tx_words--)
+ xilinx_spi_tx(xspi);
+
+ /* Start the transfer by not inhibiting the transmitter any
+ * longer
+ */
+
+ if (use_irq) {
+ xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
+ wait_for_completion(&xspi->done);
+ } else
+ while (!(xspi->read_fn(xspi->regs + XSPI_SR_OFFSET) &
+ XSPI_SR_TX_EMPTY_MASK))
+ ;
+
+ /* A transmit has just completed. Process received data and
+ * check for more data to transmit. Always inhibit the
+ * transmitter while the Isr refills the transmit register/FIFO,
+ * or make sure it is stopped if we're done.
+ */
+ if (use_irq)
+ xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
+ xspi->regs + XSPI_CR_OFFSET);
+
+ /* Read out all the data from the Rx FIFO */
+ rx_words = n_words;
+ while (rx_words--)
+ xilinx_spi_rx(xspi);
+
+ remaining_words -= n_words;
+ }
+
+ if (use_irq)
+ xspi->write_fn(0, xspi->regs + XIPIF_V123B_DGIER_OFFSET);
+
+ return t->len;
+}
+
+
+/* This driver supports single master mode only. Hence Tx FIFO Empty
+ * is the only interrupt we care about.
+ * Receive FIFO Overrun, Transmit FIFO Underrun, Mode Fault, and Slave Mode
+ * Fault are not to happen.
+ */
+static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
+{
+ struct xilinx_spi *xspi = dev_id;
+ u32 ipif_isr;
+
+ /* Get the IPIF interrupts, and clear them immediately */
+ ipif_isr = xspi->read_fn(xspi->regs + XIPIF_V123B_IISR_OFFSET);
+ xspi->write_fn(ipif_isr, xspi->regs + XIPIF_V123B_IISR_OFFSET);
+
+ if (ipif_isr & XSPI_INTR_TX_EMPTY) { /* Transmission completed */
+ complete(&xspi->done);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int xilinx_spi_find_buffer_size(struct xilinx_spi *xspi)
+{
+ u8 sr;
+ int n_words = 0;
+
+ /*
+ * Before the buffer_size detection we reset the core
+ * to make sure we start with a clean state.
+ */
+ xspi->write_fn(XIPIF_V123B_RESET_MASK,
+ xspi->regs + XIPIF_V123B_RESETR_OFFSET);
+
+ /* Fill the Tx FIFO with as many words as possible */
+ do {
+ xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
+ sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
+ n_words++;
+ } while (!(sr & XSPI_SR_TX_FULL_MASK));
+
+ return n_words;
+}
+
+static const struct of_device_id xilinx_spi_of_match[] = {
+ { .compatible = "xlnx,xps-spi-2.00.a", },
+ { .compatible = "xlnx,xps-spi-2.00.b", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, xilinx_spi_of_match);
+
+static int xilinx_spi_probe(struct platform_device *pdev)
+{
+ struct xilinx_spi *xspi;
+ struct xspi_platform_data *pdata;
+ struct resource *res;
+ int ret, num_cs = 0, bits_per_word = 8;
+ struct spi_master *master;
+ u32 tmp;
+ u8 i;
+
+ pdata = dev_get_platdata(&pdev->dev);
+ if (pdata) {
+ num_cs = pdata->num_chipselect;
+ bits_per_word = pdata->bits_per_word;
+ } else {
+ of_property_read_u32(pdev->dev.of_node, "xlnx,num-ss-bits",
+ &num_cs);
+ }
+
+ if (!num_cs) {
+ dev_err(&pdev->dev,
+ "Missing slave select configuration data\n");
+ return -EINVAL;
+ }
+
+ if (num_cs > XILINX_SPI_MAX_CS) {
+ dev_err(&pdev->dev, "Invalid number of spi slaves\n");
+ return -EINVAL;
+ }
+
+ master = spi_alloc_master(&pdev->dev, sizeof(struct xilinx_spi));
+ if (!master)
+ return -ENODEV;
+
+ /* the spi->mode bits understood by this driver: */
+ master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_LOOP |
+ SPI_CS_HIGH;
+
+ xspi = spi_master_get_devdata(master);
+ xspi->cs_inactive = 0xffffffff;
+ xspi->bitbang.master = master;
+ xspi->bitbang.chipselect = xilinx_spi_chipselect;
+ xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer;
+ xspi->bitbang.txrx_bufs = xilinx_spi_txrx_bufs;
+ init_completion(&xspi->done);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ xspi->regs = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(xspi->regs)) {
+ ret = PTR_ERR(xspi->regs);
+ goto put_master;
+ }
+
+ master->bus_num = pdev->id;
+ master->num_chipselect = num_cs;
+ master->dev.of_node = pdev->dev.of_node;
+
+ /*
+ * Detect endianess on the IP via loop bit in CR. Detection
+ * must be done before reset is sent because incorrect reset
+ * value generates error interrupt.
+ * Setup little endian helper functions first and try to use them
+ * and check if bit was correctly setup or not.
+ */
+ xspi->read_fn = xspi_read32;
+ xspi->write_fn = xspi_write32;
+
+ xspi->write_fn(XSPI_CR_LOOP, xspi->regs + XSPI_CR_OFFSET);
+ tmp = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
+ tmp &= XSPI_CR_LOOP;
+ if (tmp != XSPI_CR_LOOP) {
+ xspi->read_fn = xspi_read32_be;
+ xspi->write_fn = xspi_write32_be;
+ }
+
+ master->bits_per_word_mask = SPI_BPW_MASK(bits_per_word);
+ xspi->bytes_per_word = bits_per_word / 8;
+ xspi->buffer_size = xilinx_spi_find_buffer_size(xspi);
+
+ xspi->irq = platform_get_irq(pdev, 0);
+ if (xspi->irq >= 0) {
+ /* Register for SPI Interrupt */
+ ret = devm_request_irq(&pdev->dev, xspi->irq, xilinx_spi_irq, 0,
+ dev_name(&pdev->dev), xspi);
+ if (ret)
+ goto put_master;
+ }
+
+ /* SPI controller initializations */
+ xspi_init_hw(xspi);
+
+ ret = spi_bitbang_start(&xspi->bitbang);
+ if (ret) {
+ dev_err(&pdev->dev, "spi_bitbang_start FAILED\n");
+ goto put_master;
+ }
+
+ dev_info(&pdev->dev, "at 0x%08llX mapped to 0x%p, irq=%d\n",
+ (unsigned long long)res->start, xspi->regs, xspi->irq);
+
+ if (pdata) {
+ for (i = 0; i < pdata->num_devices; i++)
+ spi_new_device(master, pdata->devices + i);
+ }
+
+ platform_set_drvdata(pdev, master);
+ return 0;
+
+put_master:
+ spi_master_put(master);
+
+ return ret;
+}
+
+static int xilinx_spi_remove(struct platform_device *pdev)
+{
+ struct spi_master *master = platform_get_drvdata(pdev);
+ struct xilinx_spi *xspi = spi_master_get_devdata(master);
+ void __iomem *regs_base = xspi->regs;
+
+ spi_bitbang_stop(&xspi->bitbang);
+
+ /* Disable all the interrupts just in case */
+ xspi->write_fn(0, regs_base + XIPIF_V123B_IIER_OFFSET);
+ /* Disable the global IPIF interrupt */
+ xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET);
+
+ spi_master_put(xspi->bitbang.master);
+
+ return 0;
+}
+
+/* work with hotplug and coldplug */
+MODULE_ALIAS("platform:" XILINX_SPI_NAME);
+
+static struct platform_driver xilinx_spi_driver = {
+ .probe = xilinx_spi_probe,
+ .remove = xilinx_spi_remove,
+ .driver = {
+ .name = XILINX_SPI_NAME,
+ .of_match_table = xilinx_spi_of_match,
+ },
+};
+module_platform_driver(xilinx_spi_driver);
+
+MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
+MODULE_DESCRIPTION("Xilinx SPI driver");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff