--- /dev/null
+/*
+ * xilinx_spi.c
+ *
+ * Xilinx SPI controller driver (master mode only)
+ *
+ * Author: MontaVista Software, Inc.
+ * source@mvista.com
+ *
+ * 2002-2007 (c) MontaVista Software, Inc. This file is licensed under the
+ * terms of the GNU General Public License version 2. This program is licensed
+ * "as is" without any warranty of any kind, whether express or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/io.h>
+
+#include <syslib/virtex_devices.h>
+
+#define XILINX_SPI_NAME "xspi"
+
+/* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e)
+ * Product Specification", DS464
+ */
+#define XSPI_CR_OFFSET 0x62 /* 16-bit Control Register */
+
+#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)
+#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_SR_OFFSET 0x67 /* 8-bit 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 0x6b /* 8-bit Data Transmit Register */
+#define XSPI_RXD_OFFSET 0x6f /* 8-bit 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 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 */
+
+ u32 irq;
+
+ u32 speed_hz; /* SCK has a fixed frequency of speed_hz Hz */
+
+ u8 *rx_ptr; /* pointer in the Tx buffer */
+ const u8 *tx_ptr; /* pointer in the Rx buffer */
+ int remaining_bytes; /* the number of bytes left to transfer */
+};
+
+static void xspi_init_hw(void __iomem *regs_base)
+{
+ /* Reset the SPI device */
+ out_be32(regs_base + XIPIF_V123B_RESETR_OFFSET,
+ XIPIF_V123B_RESET_MASK);
+ /* Disable all the interrupts just in case */
+ out_be32(regs_base + XIPIF_V123B_IIER_OFFSET, 0);
+ /* Enable the global IPIF interrupt */
+ out_be32(regs_base + XIPIF_V123B_DGIER_OFFSET,
+ XIPIF_V123B_GINTR_ENABLE);
+ /* Deselect the slave on the SPI bus */
+ out_be32(regs_base + XSPI_SSR_OFFSET, 0xffff);
+ /* Disable the transmitter, enable Manual Slave Select Assertion,
+ * put SPI controller into master mode, and enable it */
+ out_be16(regs_base + XSPI_CR_OFFSET,
+ XSPI_CR_TRANS_INHIBIT | XSPI_CR_MANUAL_SSELECT
+ | XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE);
+}
+
+static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
+{
+ struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
+
+ if (is_on == BITBANG_CS_INACTIVE) {
+ /* Deselect the slave on the SPI bus */
+ out_be32(xspi->regs + XSPI_SSR_OFFSET, 0xffff);
+ } else if (is_on == BITBANG_CS_ACTIVE) {
+ /* Set the SPI clock phase and polarity */
+ u16 cr = in_be16(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;
+ out_be16(xspi->regs + XSPI_CR_OFFSET, cr);
+
+ /* We do not check spi->max_speed_hz here as the SPI clock
+ * frequency is not software programmable (the IP block design
+ * parameter)
+ */
+
+ /* Activate the chip select */
+ out_be32(xspi->regs + XSPI_SSR_OFFSET,
+ ~(0x0001 << spi->chip_select));
+ }
+}
+
+/* spi_bitbang requires custom setup_transfer() to be defined if there is a
+ * custom txrx_bufs(). We have nothing to setup here as the SPI IP block
+ * supports just 8 bits per word, and SPI clock can't be changed in software.
+ * Check for 8 bits per word. Chip select delay calculations could be
+ * added here as soon as bitbang_work() can be made aware of the delay value.
+ */
+static int xilinx_spi_setup_transfer(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ u8 bits_per_word;
+ u32 hz;
+ struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
+
+ bits_per_word = (t) ? t->bits_per_word : spi->bits_per_word;
+ hz = (t) ? t->speed_hz : spi->max_speed_hz;
+ if (bits_per_word != 8) {
+ dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
+ __FUNCTION__, bits_per_word);
+ return -EINVAL;
+ }
+
+ if (hz && xspi->speed_hz > hz) {
+ dev_err(&spi->dev, "%s, unsupported clock rate %uHz\n",
+ __FUNCTION__, hz);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/* the spi->mode bits understood by this driver: */
+#define MODEBITS (SPI_CPOL | SPI_CPHA)
+
+static int xilinx_spi_setup(struct spi_device *spi)
+{
+ struct spi_bitbang *bitbang;
+ struct xilinx_spi *xspi;
+ int retval;
+
+ xspi = spi_master_get_devdata(spi->master);
+ bitbang = &xspi->bitbang;
+
+ if (!spi->bits_per_word)
+ spi->bits_per_word = 8;
+
+ if (spi->mode & ~MODEBITS) {
+ dev_err(&spi->dev, "%s, unsupported mode bits %x\n",
+ __FUNCTION__, spi->mode & ~MODEBITS);
+ return -EINVAL;
+ }
+
+ retval = xilinx_spi_setup_transfer(spi, NULL);
+ if (retval < 0)
+ return retval;
+
+ dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec/bit\n",
+ __FUNCTION__, spi->mode & MODEBITS, spi->bits_per_word, 0);
+
+ return 0;
+}
+
+static void xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi)
+{
+ u8 sr;
+
+ /* Fill the Tx FIFO with as many bytes as possible */
+ sr = in_8(xspi->regs + XSPI_SR_OFFSET);
+ while ((sr & XSPI_SR_TX_FULL_MASK) == 0 && xspi->remaining_bytes > 0) {
+ if (xspi->tx_ptr) {
+ out_8(xspi->regs + XSPI_TXD_OFFSET, *xspi->tx_ptr++);
+ } else {
+ out_8(xspi->regs + XSPI_TXD_OFFSET, 0);
+ }
+ xspi->remaining_bytes--;
+ sr = in_8(xspi->regs + XSPI_SR_OFFSET);
+ }
+}
+
+static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
+{
+ struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
+ u32 ipif_ier;
+ u16 cr;
+
+ /* We get here with transmitter inhibited */
+
+ xspi->tx_ptr = t->tx_buf;
+ xspi->rx_ptr = t->rx_buf;
+ xspi->remaining_bytes = t->len;
+ INIT_COMPLETION(xspi->done);
+
+ xilinx_spi_fill_tx_fifo(xspi);
+
+ /* Enable the transmit empty interrupt, which we use to determine
+ * progress on the transmission.
+ */
+ ipif_ier = in_be32(xspi->regs + XIPIF_V123B_IIER_OFFSET);
+ out_be32(xspi->regs + XIPIF_V123B_IIER_OFFSET,
+ ipif_ier | XSPI_INTR_TX_EMPTY);
+
+ /* Start the transfer by not inhibiting the transmitter any longer */
+ cr = in_be16(xspi->regs + XSPI_CR_OFFSET) & ~XSPI_CR_TRANS_INHIBIT;
+ out_be16(xspi->regs + XSPI_CR_OFFSET, cr);
+
+ wait_for_completion(&xspi->done);
+
+ /* Disable the transmit empty interrupt */
+ out_be32(xspi->regs + XIPIF_V123B_IIER_OFFSET, ipif_ier);
+
+ return t->len - xspi->remaining_bytes;
+}
+
+
+/* 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 = in_be32(xspi->regs + XIPIF_V123B_IISR_OFFSET);
+ out_be32(xspi->regs + XIPIF_V123B_IISR_OFFSET, ipif_isr);
+
+ if (ipif_isr & XSPI_INTR_TX_EMPTY) { /* Transmission completed */
+ u16 cr;
+ u8 sr;
+
+ /* 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.
+ */
+ cr = in_be16(xspi->regs + XSPI_CR_OFFSET);
+ out_be16(xspi->regs + XSPI_CR_OFFSET,
+ cr | XSPI_CR_TRANS_INHIBIT);
+
+ /* Read out all the data from the Rx FIFO */
+ sr = in_8(xspi->regs + XSPI_SR_OFFSET);
+ while ((sr & XSPI_SR_RX_EMPTY_MASK) == 0) {
+ u8 data;
+
+ data = in_8(xspi->regs + XSPI_RXD_OFFSET);
+ if (xspi->rx_ptr) {
+ *xspi->rx_ptr++ = data;
+ }
+ sr = in_8(xspi->regs + XSPI_SR_OFFSET);
+ }
+
+ /* See if there is more data to send */
+ if (xspi->remaining_bytes > 0) {
+ xilinx_spi_fill_tx_fifo(xspi);
+ /* Start the transfer by not inhibiting the
+ * transmitter any longer
+ */
+ out_be16(xspi->regs + XSPI_CR_OFFSET, cr);
+ } else {
+ /* No more data to send.
+ * Indicate the transfer is completed.
+ */
+ complete(&xspi->done);
+ }
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int __init xilinx_spi_probe(struct platform_device *dev)
+{
+ int ret = 0;
+ struct spi_master *master;
+ struct xilinx_spi *xspi;
+ struct xspi_platform_data *pdata;
+ struct resource *r;
+
+ /* Get resources(memory, IRQ) associated with the device */
+ master = spi_alloc_master(&dev->dev, sizeof(struct xilinx_spi));
+
+ if (master == NULL) {
+ return -ENOMEM;
+ }
+
+ platform_set_drvdata(dev, master);
+ pdata = dev->dev.platform_data;
+
+ if (pdata == NULL) {
+ ret = -ENODEV;
+ goto put_master;
+ }
+
+ r = platform_get_resource(dev, IORESOURCE_MEM, 0);
+ if (r == NULL) {
+ ret = -ENODEV;
+ goto put_master;
+ }
+
+ xspi = spi_master_get_devdata(master);
+ xspi->bitbang.master = spi_master_get(master);
+ xspi->bitbang.chipselect = xilinx_spi_chipselect;
+ xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer;
+ xspi->bitbang.txrx_bufs = xilinx_spi_txrx_bufs;
+ xspi->bitbang.master->setup = xilinx_spi_setup;
+ init_completion(&xspi->done);
+
+ if (!request_mem_region(r->start,
+ r->end - r->start + 1, XILINX_SPI_NAME)) {
+ ret = -ENXIO;
+ goto put_master;
+ }
+
+ xspi->regs = ioremap(r->start, r->end - r->start + 1);
+ if (xspi->regs == NULL) {
+ ret = -ENOMEM;
+ goto put_master;
+ }
+
+ xspi->irq = platform_get_irq(dev, 0);
+ if (xspi->irq < 0) {
+ ret = -ENXIO;
+ goto unmap_io;
+ }
+
+ master->bus_num = pdata->bus_num;
+ master->num_chipselect = pdata->num_chipselect;
+ xspi->speed_hz = pdata->speed_hz;
+
+ /* SPI controller initializations */
+ xspi_init_hw(xspi->regs);
+
+ /* Register for SPI Interrupt */
+ ret = request_irq(xspi->irq, xilinx_spi_irq, 0, XILINX_SPI_NAME, xspi);
+ if (ret != 0)
+ goto unmap_io;
+
+ ret = spi_bitbang_start(&xspi->bitbang);
+ if (ret != 0) {
+ dev_err(&dev->dev, "spi_bitbang_start FAILED\n");
+ goto free_irq;
+ }
+
+ dev_info(&dev->dev, "at 0x%08X mapped to 0x%08X, irq=%d\n",
+ r->start, (u32)xspi->regs, xspi->irq);
+
+ return ret;
+
+free_irq:
+ free_irq(xspi->irq, xspi);
+unmap_io:
+ iounmap(xspi->regs);
+put_master:
+ spi_master_put(master);
+ return ret;
+}
+
+static int __devexit xilinx_spi_remove(struct platform_device *dev)
+{
+ struct xilinx_spi *xspi;
+ struct spi_master *master;
+
+ master = platform_get_drvdata(dev);
+ xspi = spi_master_get_devdata(master);
+
+ spi_bitbang_stop(&xspi->bitbang);
+ free_irq(xspi->irq, xspi);
+ iounmap(xspi->regs);
+ platform_set_drvdata(dev, 0);
+ spi_master_put(xspi->bitbang.master);
+
+ return 0;
+}
+
+static struct platform_driver xilinx_spi_driver = {
+ .probe = xilinx_spi_probe,
+ .remove = __devexit_p(xilinx_spi_remove),
+ .driver = {
+ .name = XILINX_SPI_NAME,
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init xilinx_spi_init(void)
+{
+ return platform_driver_register(&xilinx_spi_driver);
+}
+module_init(xilinx_spi_init);
+
+static void __exit xilinx_spi_exit(void)
+{
+ platform_driver_unregister(&xilinx_spi_driver);
+}
+module_exit(xilinx_spi_exit);
+
+MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
+MODULE_DESCRIPTION("Xilinx SPI driver");
+MODULE_LICENSE("GPL");
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff