--- /dev/null
+/*
+ * Copyright (C) 2011-2015 Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
+ * Copyright (C) 2016 Hauke Mehrtens <hauke@hauke-m.de>
+ *
+ * This program is free software; you can distribute 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/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/completion.h>
+#include <linux/spinlock.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/pm_runtime.h>
+#include <linux/spi/spi.h>
+
+#ifdef CONFIG_LANTIQ
+#include <lantiq_soc.h>
+#endif
+
+#define SPI_RX_IRQ_NAME "spi_rx"
+#define SPI_TX_IRQ_NAME "spi_tx"
+#define SPI_ERR_IRQ_NAME "spi_err"
+#define SPI_FRM_IRQ_NAME "spi_frm"
+
+#define SPI_CLC 0x00
+#define SPI_PISEL 0x04
+#define SPI_ID 0x08
+#define SPI_CON 0x10
+#define SPI_STAT 0x14
+#define SPI_WHBSTATE 0x18
+#define SPI_TB 0x20
+#define SPI_RB 0x24
+#define SPI_RXFCON 0x30
+#define SPI_TXFCON 0x34
+#define SPI_FSTAT 0x38
+#define SPI_BRT 0x40
+#define SPI_BRSTAT 0x44
+#define SPI_SFCON 0x60
+#define SPI_SFSTAT 0x64
+#define SPI_GPOCON 0x70
+#define SPI_GPOSTAT 0x74
+#define SPI_FPGO 0x78
+#define SPI_RXREQ 0x80
+#define SPI_RXCNT 0x84
+#define SPI_DMACON 0xec
+#define SPI_IRNEN 0xf4
+#define SPI_IRNICR 0xf8
+#define SPI_IRNCR 0xfc
+
+#define SPI_CLC_SMC_S 16 /* Clock divider for sleep mode */
+#define SPI_CLC_SMC_M (0xFF << SPI_CLC_SMC_S)
+#define SPI_CLC_RMC_S 8 /* Clock divider for normal run mode */
+#define SPI_CLC_RMC_M (0xFF << SPI_CLC_RMC_S)
+#define SPI_CLC_DISS BIT(1) /* Disable status bit */
+#define SPI_CLC_DISR BIT(0) /* Disable request bit */
+
+#define SPI_ID_TXFS_S 24 /* Implemented TX FIFO size */
+#define SPI_ID_TXFS_M (0x3F << SPI_ID_TXFS_S)
+#define SPI_ID_RXFS_S 16 /* Implemented RX FIFO size */
+#define SPI_ID_RXFS_M (0x3F << SPI_ID_RXFS_S)
+#define SPI_ID_MOD_S 8 /* Module ID */
+#define SPI_ID_MOD_M (0xff << SPI_ID_MOD_S)
+#define SPI_ID_CFG_S 5 /* DMA interface support */
+#define SPI_ID_CFG_M (1 << SPI_ID_CFG_S)
+#define SPI_ID_REV_M 0x1F /* Hardware revision number */
+
+#define SPI_CON_BM_S 16 /* Data width selection */
+#define SPI_CON_BM_M (0x1F << SPI_CON_BM_S)
+#define SPI_CON_EM BIT(24) /* Echo mode */
+#define SPI_CON_IDLE BIT(23) /* Idle bit value */
+#define SPI_CON_ENBV BIT(22) /* Enable byte valid control */
+#define SPI_CON_RUEN BIT(12) /* Receive underflow error enable */
+#define SPI_CON_TUEN BIT(11) /* Transmit underflow error enable */
+#define SPI_CON_AEN BIT(10) /* Abort error enable */
+#define SPI_CON_REN BIT(9) /* Receive overflow error enable */
+#define SPI_CON_TEN BIT(8) /* Transmit overflow error enable */
+#define SPI_CON_LB BIT(7) /* Loopback control */
+#define SPI_CON_PO BIT(6) /* Clock polarity control */
+#define SPI_CON_PH BIT(5) /* Clock phase control */
+#define SPI_CON_HB BIT(4) /* Heading control */
+#define SPI_CON_RXOFF BIT(1) /* Switch receiver off */
+#define SPI_CON_TXOFF BIT(0) /* Switch transmitter off */
+
+#define SPI_STAT_RXBV_S 28
+#define SPI_STAT_RXBV_M (0x7 << SPI_STAT_RXBV_S)
+#define SPI_STAT_BSY BIT(13) /* Busy flag */
+#define SPI_STAT_RUE BIT(12) /* Receive underflow error flag */
+#define SPI_STAT_TUE BIT(11) /* Transmit underflow error flag */
+#define SPI_STAT_AE BIT(10) /* Abort error flag */
+#define SPI_STAT_RE BIT(9) /* Receive error flag */
+#define SPI_STAT_TE BIT(8) /* Transmit error flag */
+#define SPI_STAT_ME BIT(7) /* Mode error flag */
+#define SPI_STAT_MS BIT(1) /* Master/slave select bit */
+#define SPI_STAT_EN BIT(0) /* Enable bit */
+#define SPI_STAT_ERRORS (SPI_STAT_ME | SPI_STAT_TE | SPI_STAT_RE | \
+ SPI_STAT_AE | SPI_STAT_TUE | SPI_STAT_RUE)
+
+#define SPI_WHBSTATE_SETTUE BIT(15) /* Set transmit underflow error flag */
+#define SPI_WHBSTATE_SETAE BIT(14) /* Set abort error flag */
+#define SPI_WHBSTATE_SETRE BIT(13) /* Set receive error flag */
+#define SPI_WHBSTATE_SETTE BIT(12) /* Set transmit error flag */
+#define SPI_WHBSTATE_CLRTUE BIT(11) /* Clear transmit underflow error flag */
+#define SPI_WHBSTATE_CLRAE BIT(10) /* Clear abort error flag */
+#define SPI_WHBSTATE_CLRRE BIT(9) /* Clear receive error flag */
+#define SPI_WHBSTATE_CLRTE BIT(8) /* Clear transmit error flag */
+#define SPI_WHBSTATE_SETME BIT(7) /* Set mode error flag */
+#define SPI_WHBSTATE_CLRME BIT(6) /* Clear mode error flag */
+#define SPI_WHBSTATE_SETRUE BIT(5) /* Set receive underflow error flag */
+#define SPI_WHBSTATE_CLRRUE BIT(4) /* Clear receive underflow error flag */
+#define SPI_WHBSTATE_SETMS BIT(3) /* Set master select bit */
+#define SPI_WHBSTATE_CLRMS BIT(2) /* Clear master select bit */
+#define SPI_WHBSTATE_SETEN BIT(1) /* Set enable bit (operational mode) */
+#define SPI_WHBSTATE_CLREN BIT(0) /* Clear enable bit (config mode */
+#define SPI_WHBSTATE_CLR_ERRORS (SPI_WHBSTATE_CLRRUE | SPI_WHBSTATE_CLRME | \
+ SPI_WHBSTATE_CLRTE | SPI_WHBSTATE_CLRRE | \
+ SPI_WHBSTATE_CLRAE | SPI_WHBSTATE_CLRTUE)
+
+#define SPI_RXFCON_RXFITL_S 8 /* FIFO interrupt trigger level */
+#define SPI_RXFCON_RXFITL_M (0x3F << SPI_RXFCON_RXFITL_S)
+#define SPI_RXFCON_RXFLU BIT(1) /* FIFO flush */
+#define SPI_RXFCON_RXFEN BIT(0) /* FIFO enable */
+
+#define SPI_TXFCON_TXFITL_S 8 /* FIFO interrupt trigger level */
+#define SPI_TXFCON_TXFITL_M (0x3F << SPI_TXFCON_TXFITL_S)
+#define SPI_TXFCON_TXFLU BIT(1) /* FIFO flush */
+#define SPI_TXFCON_TXFEN BIT(0) /* FIFO enable */
+
+#define SPI_FSTAT_RXFFL_S 0
+#define SPI_FSTAT_RXFFL_M (0x3f << SPI_FSTAT_RXFFL_S)
+#define SPI_FSTAT_TXFFL_S 8
+#define SPI_FSTAT_TXFFL_M (0x3f << SPI_FSTAT_TXFFL_S)
+
+#define SPI_GPOCON_ISCSBN_S 8
+#define SPI_GPOCON_INVOUTN_S 0
+
+#define SPI_FGPO_SETOUTN_S 8
+#define SPI_FGPO_CLROUTN_S 0
+
+#define SPI_RXREQ_RXCNT_M 0xFFFF /* Receive count value */
+#define SPI_RXCNT_TODO_M 0xFFFF /* Recevie to-do value */
+
+#define SPI_IRNEN_TFI BIT(4) /* TX finished interrupt */
+#define SPI_IRNEN_F BIT(3) /* Frame end interrupt request */
+#define SPI_IRNEN_E BIT(2) /* Error end interrupt request */
+#define SPI_IRNEN_T_XWAY BIT(1) /* Transmit end interrupt request */
+#define SPI_IRNEN_R_XWAY BIT(0) /* Receive end interrupt request */
+#define SPI_IRNEN_R_XRX BIT(1) /* Transmit end interrupt request */
+#define SPI_IRNEN_T_XRX BIT(0) /* Receive end interrupt request */
+#define SPI_IRNEN_ALL 0x1F
+
+struct lantiq_ssc_hwcfg {
+ unsigned int irnen_r;
+ unsigned int irnen_t;
+};
+
+struct lantiq_ssc_spi {
+ struct spi_master *master;
+ struct device *dev;
+ void __iomem *regbase;
+ struct clk *spi_clk;
+ struct clk *fpi_clk;
+ const struct lantiq_ssc_hwcfg *hwcfg;
+
+ spinlock_t lock;
+ struct workqueue_struct *wq;
+ struct work_struct work;
+
+ const u8 *tx;
+ u8 *rx;
+ unsigned int tx_todo;
+ unsigned int rx_todo;
+ unsigned int bits_per_word;
+ unsigned int speed_hz;
+ unsigned int tx_fifo_size;
+ unsigned int rx_fifo_size;
+ unsigned int base_cs;
+};
+
+static u32 lantiq_ssc_readl(const struct lantiq_ssc_spi *spi, u32 reg)
+{
+ return __raw_readl(spi->regbase + reg);
+}
+
+static void lantiq_ssc_writel(const struct lantiq_ssc_spi *spi, u32 val,
+ u32 reg)
+{
+ __raw_writel(val, spi->regbase + reg);
+}
+
+static void lantiq_ssc_maskl(const struct lantiq_ssc_spi *spi, u32 clr,
+ u32 set, u32 reg)
+{
+ u32 val = __raw_readl(spi->regbase + reg);
+
+ val &= ~clr;
+ val |= set;
+ __raw_writel(val, spi->regbase + reg);
+}
+
+static unsigned int tx_fifo_level(const struct lantiq_ssc_spi *spi)
+{
+ u32 fstat = lantiq_ssc_readl(spi, SPI_FSTAT);
+
+ return (fstat & SPI_FSTAT_TXFFL_M) >> SPI_FSTAT_TXFFL_S;
+}
+
+static unsigned int rx_fifo_level(const struct lantiq_ssc_spi *spi)
+{
+ u32 fstat = lantiq_ssc_readl(spi, SPI_FSTAT);
+
+ return fstat & SPI_FSTAT_RXFFL_M;
+}
+
+static unsigned int tx_fifo_free(const struct lantiq_ssc_spi *spi)
+{
+ return spi->tx_fifo_size - tx_fifo_level(spi);
+}
+
+static void rx_fifo_reset(const struct lantiq_ssc_spi *spi)
+{
+ u32 val = spi->rx_fifo_size << SPI_RXFCON_RXFITL_S;
+
+ val |= SPI_RXFCON_RXFEN | SPI_RXFCON_RXFLU;
+ lantiq_ssc_writel(spi, val, SPI_RXFCON);
+}
+
+static void tx_fifo_reset(const struct lantiq_ssc_spi *spi)
+{
+ u32 val = 1 << SPI_TXFCON_TXFITL_S;
+
+ val |= SPI_TXFCON_TXFEN | SPI_TXFCON_TXFLU;
+ lantiq_ssc_writel(spi, val, SPI_TXFCON);
+}
+
+static void rx_fifo_flush(const struct lantiq_ssc_spi *spi)
+{
+ lantiq_ssc_maskl(spi, 0, SPI_RXFCON_RXFLU, SPI_RXFCON);
+}
+
+static void tx_fifo_flush(const struct lantiq_ssc_spi *spi)
+{
+ lantiq_ssc_maskl(spi, 0, SPI_TXFCON_TXFLU, SPI_TXFCON);
+}
+
+static void hw_enter_config_mode(const struct lantiq_ssc_spi *spi)
+{
+ lantiq_ssc_writel(spi, SPI_WHBSTATE_CLREN, SPI_WHBSTATE);
+}
+
+static void hw_enter_active_mode(const struct lantiq_ssc_spi *spi)
+{
+ lantiq_ssc_writel(spi, SPI_WHBSTATE_SETEN, SPI_WHBSTATE);
+}
+
+static void hw_setup_speed_hz(const struct lantiq_ssc_spi *spi,
+ unsigned int max_speed_hz)
+{
+ u32 spi_clk, brt;
+
+ /*
+ * SPI module clock is derived from FPI bus clock dependent on
+ * divider value in CLC.RMS which is always set to 1.
+ *
+ * f_SPI
+ * baudrate = --------------
+ * 2 * (BR + 1)
+ */
+ spi_clk = clk_get_rate(spi->fpi_clk) / 2;
+
+ if (max_speed_hz > spi_clk)
+ brt = 0;
+ else
+ brt = spi_clk / max_speed_hz - 1;
+
+ if (brt > 0xFFFF)
+ brt = 0xFFFF;
+
+ dev_dbg(spi->dev, "spi_clk %u, max_speed_hz %u, brt %u\n",
+ spi_clk, max_speed_hz, brt);
+
+ lantiq_ssc_writel(spi, brt, SPI_BRT);
+}
+
+static void hw_setup_bits_per_word(const struct lantiq_ssc_spi *spi,
+ unsigned int bits_per_word)
+{
+ u32 bm;
+
+ /* CON.BM value = bits_per_word - 1 */
+ bm = (bits_per_word - 1) << SPI_CON_BM_S;
+
+ lantiq_ssc_maskl(spi, SPI_CON_BM_M, bm, SPI_CON);
+}
+
+static void hw_setup_clock_mode(const struct lantiq_ssc_spi *spi,
+ unsigned int mode)
+{
+ u32 con_set = 0, con_clr = 0;
+
+ /*
+ * SPI mode mapping in CON register:
+ * Mode CPOL CPHA CON.PO CON.PH
+ * 0 0 0 0 1
+ * 1 0 1 0 0
+ * 2 1 0 1 1
+ * 3 1 1 1 0
+ */
+ if (mode & SPI_CPHA)
+ con_clr |= SPI_CON_PH;
+ else
+ con_set |= SPI_CON_PH;
+
+ if (mode & SPI_CPOL)
+ con_set |= SPI_CON_PO | SPI_CON_IDLE;
+ else
+ con_clr |= SPI_CON_PO | SPI_CON_IDLE;
+
+ /* Set heading control */
+ if (mode & SPI_LSB_FIRST)
+ con_clr |= SPI_CON_HB;
+ else
+ con_set |= SPI_CON_HB;
+
+ /* Set loopback mode */
+ if (mode & SPI_LOOP)
+ con_set |= SPI_CON_LB;
+ else
+ con_clr |= SPI_CON_LB;
+
+ lantiq_ssc_maskl(spi, con_clr, con_set, SPI_CON);
+}
+
+static void lantiq_ssc_hw_init(const struct lantiq_ssc_spi *spi)
+{
+ const struct lantiq_ssc_hwcfg *hwcfg = spi->hwcfg;
+
+ /*
+ * Set clock divider for run mode to 1 to
+ * run at same frequency as FPI bus
+ */
+ lantiq_ssc_writel(spi, 1 << SPI_CLC_RMC_S, SPI_CLC);
+
+ /* Put controller into config mode */
+ hw_enter_config_mode(spi);
+
+ /* Clear error flags */
+ lantiq_ssc_maskl(spi, 0, SPI_WHBSTATE_CLR_ERRORS, SPI_WHBSTATE);
+
+ /* Enable error checking, disable TX/RX */
+ lantiq_ssc_writel(spi, SPI_CON_RUEN | SPI_CON_AEN | SPI_CON_TEN |
+ SPI_CON_REN | SPI_CON_TXOFF | SPI_CON_RXOFF, SPI_CON);
+
+ /* Setup default SPI mode */
+ hw_setup_bits_per_word(spi, spi->bits_per_word);
+ hw_setup_clock_mode(spi, SPI_MODE_0);
+
+ /* Enable master mode and clear error flags */
+ lantiq_ssc_writel(spi, SPI_WHBSTATE_SETMS | SPI_WHBSTATE_CLR_ERRORS,
+ SPI_WHBSTATE);
+
+ /* Reset GPIO/CS registers */
+ lantiq_ssc_writel(spi, 0, SPI_GPOCON);
+ lantiq_ssc_writel(spi, 0xFF00, SPI_FPGO);
+
+ /* Enable and flush FIFOs */
+ rx_fifo_reset(spi);
+ tx_fifo_reset(spi);
+
+ /* Enable interrupts */
+ lantiq_ssc_writel(spi, hwcfg->irnen_t | hwcfg->irnen_r | SPI_IRNEN_E,
+ SPI_IRNEN);
+}
+
+static int lantiq_ssc_setup(struct spi_device *spidev)
+{
+ struct spi_master *master = spidev->master;
+ struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
+ unsigned int cs = spidev->chip_select;
+ u32 gpocon;
+
+ /* GPIOs are used for CS */
+ if (gpio_is_valid(spidev->cs_gpio))
+ return 0;
+
+ dev_dbg(spi->dev, "using internal chipselect %u\n", cs);
+
+ if (cs < spi->base_cs) {
+ dev_err(spi->dev,
+ "chipselect %i too small (min %i)\n", cs, spi->base_cs);
+ return -EINVAL;
+ }
+
+ /* set GPO pin to CS mode */
+ gpocon = 1 << ((cs - spi->base_cs) + SPI_GPOCON_ISCSBN_S);
+
+ /* invert GPO pin */
+ if (spidev->mode & SPI_CS_HIGH)
+ gpocon |= 1 << (cs - spi->base_cs);
+
+ lantiq_ssc_maskl(spi, 0, gpocon, SPI_GPOCON);
+
+ return 0;
+}
+
+static int lantiq_ssc_prepare_message(struct spi_master *master,
+ struct spi_message *message)
+{
+ struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
+
+ hw_enter_config_mode(spi);
+ hw_setup_clock_mode(spi, message->spi->mode);
+ hw_enter_active_mode(spi);
+
+ return 0;
+}
+
+static void hw_setup_transfer(struct lantiq_ssc_spi *spi,
+ struct spi_device *spidev, struct spi_transfer *t)
+{
+ unsigned int speed_hz = t->speed_hz;
+ unsigned int bits_per_word = t->bits_per_word;
+ u32 con;
+
+ if (bits_per_word != spi->bits_per_word ||
+ speed_hz != spi->speed_hz) {
+ hw_enter_config_mode(spi);
+ hw_setup_speed_hz(spi, speed_hz);
+ hw_setup_bits_per_word(spi, bits_per_word);
+ hw_enter_active_mode(spi);
+
+ spi->speed_hz = speed_hz;
+ spi->bits_per_word = bits_per_word;
+ }
+
+ /* Configure transmitter and receiver */
+ con = lantiq_ssc_readl(spi, SPI_CON);
+ if (t->tx_buf)
+ con &= ~SPI_CON_TXOFF;
+ else
+ con |= SPI_CON_TXOFF;
+
+ if (t->rx_buf)
+ con &= ~SPI_CON_RXOFF;
+ else
+ con |= SPI_CON_RXOFF;
+
+ lantiq_ssc_writel(spi, con, SPI_CON);
+}
+
+static int lantiq_ssc_unprepare_message(struct spi_master *master,
+ struct spi_message *message)
+{
+ struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
+
+ flush_workqueue(spi->wq);
+
+ /* Disable transmitter and receiver while idle */
+ lantiq_ssc_maskl(spi, 0, SPI_CON_TXOFF | SPI_CON_RXOFF, SPI_CON);
+
+ return 0;
+}
+
+static void tx_fifo_write(struct lantiq_ssc_spi *spi)
+{
+ const u8 *tx8;
+ const u16 *tx16;
+ const u32 *tx32;
+ u32 data;
+ unsigned int tx_free = tx_fifo_free(spi);
+
+ while (spi->tx_todo && tx_free) {
+ switch (spi->bits_per_word) {
+ case 2 ... 8:
+ tx8 = spi->tx;
+ data = *tx8;
+ spi->tx_todo--;
+ spi->tx++;
+ break;
+ case 16:
+ tx16 = (u16 *) spi->tx;
+ data = *tx16;
+ spi->tx_todo -= 2;
+ spi->tx += 2;
+ break;
+ case 32:
+ tx32 = (u32 *) spi->tx;
+ data = *tx32;
+ spi->tx_todo -= 4;
+ spi->tx += 4;
+ break;
+ default:
+ WARN_ON(1);
+ data = 0;
+ break;
+ }
+
+ lantiq_ssc_writel(spi, data, SPI_TB);
+ tx_free--;
+ }
+}
+
+static void rx_fifo_read_full_duplex(struct lantiq_ssc_spi *spi)
+{
+ u8 *rx8;
+ u16 *rx16;
+ u32 *rx32;
+ u32 data;
+ unsigned int rx_fill = rx_fifo_level(spi);
+
+ while (rx_fill) {
+ data = lantiq_ssc_readl(spi, SPI_RB);
+
+ switch (spi->bits_per_word) {
+ case 2 ... 8:
+ rx8 = spi->rx;
+ *rx8 = data;
+ spi->rx_todo--;
+ spi->rx++;
+ break;
+ case 16:
+ rx16 = (u16 *) spi->rx;
+ *rx16 = data;
+ spi->rx_todo -= 2;
+ spi->rx += 2;
+ break;
+ case 32:
+ rx32 = (u32 *) spi->rx;
+ *rx32 = data;
+ spi->rx_todo -= 4;
+ spi->rx += 4;
+ break;
+ default:
+ WARN_ON(1);
+ break;
+ }
+
+ rx_fill--;
+ }
+}
+
+static void rx_fifo_read_half_duplex(struct lantiq_ssc_spi *spi)
+{
+ u32 data, *rx32;
+ u8 *rx8;
+ unsigned int rxbv, shift;
+ unsigned int rx_fill = rx_fifo_level(spi);
+
+ /*
+ * In RX-only mode the bits per word value is ignored by HW. A value
+ * of 32 is used instead. Thus all 4 bytes per FIFO must be read.
+ * If remaining RX bytes are less than 4, the FIFO must be read
+ * differently. The amount of received and valid bytes is indicated
+ * by STAT.RXBV register value.
+ */
+ while (rx_fill) {
+ if (spi->rx_todo < 4) {
+ rxbv = (lantiq_ssc_readl(spi, SPI_STAT) &
+ SPI_STAT_RXBV_M) >> SPI_STAT_RXBV_S;
+ data = lantiq_ssc_readl(spi, SPI_RB);
+
+ shift = (rxbv - 1) * 8;
+ rx8 = spi->rx;
+
+ while (rxbv) {
+ *rx8++ = (data >> shift) & 0xFF;
+ rxbv--;
+ shift -= 8;
+ spi->rx_todo--;
+ spi->rx++;
+ }
+ } else {
+ data = lantiq_ssc_readl(spi, SPI_RB);
+ rx32 = (u32 *) spi->rx;
+
+ *rx32++ = data;
+ spi->rx_todo -= 4;
+ spi->rx += 4;
+ }
+ rx_fill--;
+ }
+}
+
+static void rx_request(struct lantiq_ssc_spi *spi)
+{
+ unsigned int rxreq, rxreq_max;
+
+ /*
+ * To avoid receive overflows at high clocks it is better to request
+ * only the amount of bytes that fits into all FIFOs. This value
+ * depends on the FIFO size implemented in hardware.
+ */
+ rxreq = spi->rx_todo;
+ rxreq_max = spi->rx_fifo_size * 4;
+ if (rxreq > rxreq_max)
+ rxreq = rxreq_max;
+
+ lantiq_ssc_writel(spi, rxreq, SPI_RXREQ);
+}
+
+static irqreturn_t lantiq_ssc_xmit_interrupt(int irq, void *data)
+{
+ struct lantiq_ssc_spi *spi = data;
+
+ if (spi->tx) {
+ if (spi->rx && spi->rx_todo)
+ rx_fifo_read_full_duplex(spi);
+
+ if (spi->tx_todo)
+ tx_fifo_write(spi);
+ else if (!tx_fifo_level(spi))
+ goto completed;
+ } else if (spi->rx) {
+ if (spi->rx_todo) {
+ rx_fifo_read_half_duplex(spi);
+
+ if (spi->rx_todo)
+ rx_request(spi);
+ else
+ goto completed;
+ } else {
+ goto completed;
+ }
+ }
+
+ return IRQ_HANDLED;
+
+completed:
+ queue_work(spi->wq, &spi->work);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t lantiq_ssc_err_interrupt(int irq, void *data)
+{
+ struct lantiq_ssc_spi *spi = data;
+ u32 stat = lantiq_ssc_readl(spi, SPI_STAT);
+
+ if (!(stat & SPI_STAT_ERRORS))
+ return IRQ_NONE;
+
+ if (stat & SPI_STAT_RUE)
+ dev_err(spi->dev, "receive underflow error\n");
+ if (stat & SPI_STAT_TUE)
+ dev_err(spi->dev, "transmit underflow error\n");
+ if (stat & SPI_STAT_AE)
+ dev_err(spi->dev, "abort error\n");
+ if (stat & SPI_STAT_RE)
+ dev_err(spi->dev, "receive overflow error\n");
+ if (stat & SPI_STAT_TE)
+ dev_err(spi->dev, "transmit overflow error\n");
+ if (stat & SPI_STAT_ME)
+ dev_err(spi->dev, "mode error\n");
+
+ /* Clear error flags */
+ lantiq_ssc_maskl(spi, 0, SPI_WHBSTATE_CLR_ERRORS, SPI_WHBSTATE);
+
+ /* set bad status so it can be retried */
+ if (spi->master->cur_msg)
+ spi->master->cur_msg->status = -EIO;
+ queue_work(spi->wq, &spi->work);
+
+ return IRQ_HANDLED;
+}
+
+static int transfer_start(struct lantiq_ssc_spi *spi, struct spi_device *spidev,
+ struct spi_transfer *t)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&spi->lock, flags);
+
+ spi->tx = t->tx_buf;
+ spi->rx = t->rx_buf;
+
+ if (t->tx_buf) {
+ spi->tx_todo = t->len;
+
+ /* initially fill TX FIFO */
+ tx_fifo_write(spi);
+ }
+
+ if (spi->rx) {
+ spi->rx_todo = t->len;
+
+ /* start shift clock in RX-only mode */
+ if (!spi->tx)
+ rx_request(spi);
+ }
+
+ spin_unlock_irqrestore(&spi->lock, flags);
+
+ return t->len;
+}
+
+/*
+ * The driver only gets an interrupt when the FIFO is empty, but there
+ * is an additional shift register from which the data is written to
+ * the wire. We get the last interrupt when the controller starts to
+ * write the last word to the wire, not when it is finished. Do busy
+ * waiting till it finishes.
+ */
+static void lantiq_ssc_bussy_work(struct work_struct *work)
+{
+ struct lantiq_ssc_spi *spi;
+ unsigned long long timeout = 8LL * 1000LL;
+ unsigned long end;
+
+ spi = container_of(work, typeof(*spi), work);
+
+ do_div(timeout, spi->speed_hz);
+ timeout += timeout + 100; /* some tolerance */
+
+ end = jiffies + msecs_to_jiffies(timeout);
+ do {
+ u32 stat = lantiq_ssc_readl(spi, SPI_STAT);
+
+ if (!(stat & SPI_STAT_BSY)) {
+ spi_finalize_current_transfer(spi->master);
+ return;
+ }
+
+ cond_resched();
+ } while (!time_after_eq(jiffies, end));
+
+ if (spi->master->cur_msg)
+ spi->master->cur_msg->status = -EIO;
+ spi_finalize_current_transfer(spi->master);
+}
+
+static void lantiq_ssc_handle_err(struct spi_master *master,
+ struct spi_message *message)
+{
+ struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
+
+ /* flush FIFOs on timeout */
+ rx_fifo_flush(spi);
+ tx_fifo_flush(spi);
+}
+
+static void lantiq_ssc_set_cs(struct spi_device *spidev, bool enable)
+{
+ struct lantiq_ssc_spi *spi = spi_master_get_devdata(spidev->master);
+ unsigned int cs = spidev->chip_select;
+ u32 fgpo;
+
+ if (!!(spidev->mode & SPI_CS_HIGH) == enable)
+ fgpo = (1 << (cs - spi->base_cs));
+ else
+ fgpo = (1 << (cs - spi->base_cs + SPI_FGPO_SETOUTN_S));
+
+ lantiq_ssc_writel(spi, fgpo, SPI_FPGO);
+}
+
+static int lantiq_ssc_transfer_one(struct spi_master *master,
+ struct spi_device *spidev,
+ struct spi_transfer *t)
+{
+ struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
+
+ hw_setup_transfer(spi, spidev, t);
+
+ return transfer_start(spi, spidev, t);
+}
+
+static const struct lantiq_ssc_hwcfg lantiq_ssc_xway = {
+ .irnen_r = SPI_IRNEN_R_XWAY,
+ .irnen_t = SPI_IRNEN_T_XWAY,
+};
+
+static const struct lantiq_ssc_hwcfg lantiq_ssc_xrx = {
+ .irnen_r = SPI_IRNEN_R_XRX,
+ .irnen_t = SPI_IRNEN_T_XRX,
+};
+
+static const struct of_device_id lantiq_ssc_match[] = {
+ { .compatible = "lantiq,ase-spi", .data = &lantiq_ssc_xway, },
+ { .compatible = "lantiq,falcon-spi", .data = &lantiq_ssc_xrx, },
+ { .compatible = "lantiq,xrx100-spi", .data = &lantiq_ssc_xrx, },
+ {},
+};
+MODULE_DEVICE_TABLE(of, lantiq_ssc_match);
+
+static int lantiq_ssc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct spi_master *master;
+ struct resource *res;
+ struct lantiq_ssc_spi *spi;
+ const struct lantiq_ssc_hwcfg *hwcfg;
+ const struct of_device_id *match;
+ int err, rx_irq, tx_irq, err_irq;
+ u32 id, supports_dma, revision;
+ unsigned int num_cs;
+
+ match = of_match_device(lantiq_ssc_match, dev);
+ if (!match) {
+ dev_err(dev, "no device match\n");
+ return -EINVAL;
+ }
+ hwcfg = match->data;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(dev, "failed to get resources\n");
+ return -ENXIO;
+ }
+
+ rx_irq = platform_get_irq_byname(pdev, SPI_RX_IRQ_NAME);
+ if (rx_irq < 0) {
+ dev_err(dev, "failed to get %s\n", SPI_RX_IRQ_NAME);
+ return -ENXIO;
+ }
+
+ tx_irq = platform_get_irq_byname(pdev, SPI_TX_IRQ_NAME);
+ if (tx_irq < 0) {
+ dev_err(dev, "failed to get %s\n", SPI_TX_IRQ_NAME);
+ return -ENXIO;
+ }
+
+ err_irq = platform_get_irq_byname(pdev, SPI_ERR_IRQ_NAME);
+ if (err_irq < 0) {
+ dev_err(dev, "failed to get %s\n", SPI_ERR_IRQ_NAME);
+ return -ENXIO;
+ }
+
+ master = spi_alloc_master(dev, sizeof(struct lantiq_ssc_spi));
+ if (!master)
+ return -ENOMEM;
+
+ spi = spi_master_get_devdata(master);
+ spi->master = master;
+ spi->dev = dev;
+ spi->hwcfg = hwcfg;
+ platform_set_drvdata(pdev, spi);
+
+ spi->regbase = devm_ioremap_resource(dev, res);
+ if (IS_ERR(spi->regbase)) {
+ err = PTR_ERR(spi->regbase);
+ goto err_master_put;
+ }
+
+ err = devm_request_irq(dev, rx_irq, lantiq_ssc_xmit_interrupt,
+ 0, SPI_RX_IRQ_NAME, spi);
+ if (err)
+ goto err_master_put;
+
+ err = devm_request_irq(dev, tx_irq, lantiq_ssc_xmit_interrupt,
+ 0, SPI_TX_IRQ_NAME, spi);
+ if (err)
+ goto err_master_put;
+
+ err = devm_request_irq(dev, err_irq, lantiq_ssc_err_interrupt,
+ 0, SPI_ERR_IRQ_NAME, spi);
+ if (err)
+ goto err_master_put;
+
+ spi->spi_clk = devm_clk_get(dev, "gate");
+ if (IS_ERR(spi->spi_clk)) {
+ err = PTR_ERR(spi->spi_clk);
+ goto err_master_put;
+ }
+ err = clk_prepare_enable(spi->spi_clk);
+ if (err)
+ goto err_master_put;
+
+ /*
+ * Use the old clk_get_fpi() function on Lantiq platform, till it
+ * supports common clk.
+ */
+#if defined(CONFIG_LANTIQ) && !defined(CONFIG_COMMON_CLK)
+ spi->fpi_clk = clk_get_fpi();
+#else
+ spi->fpi_clk = clk_get(dev, "freq");
+#endif
+ if (IS_ERR(spi->fpi_clk)) {
+ err = PTR_ERR(spi->fpi_clk);
+ goto err_clk_disable;
+ }
+
+ num_cs = 8;
+ of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs);
+
+ spi->base_cs = 1;
+ of_property_read_u32(pdev->dev.of_node, "base-cs", &spi->base_cs);
+
+ spin_lock_init(&spi->lock);
+ spi->bits_per_word = 8;
+ spi->speed_hz = 0;
+
+ master->dev.of_node = pdev->dev.of_node;
+ master->num_chipselect = num_cs;
+ master->setup = lantiq_ssc_setup;
+ master->set_cs = lantiq_ssc_set_cs;
+ master->handle_err = lantiq_ssc_handle_err;
+ master->prepare_message = lantiq_ssc_prepare_message;
+ master->unprepare_message = lantiq_ssc_unprepare_message;
+ master->transfer_one = lantiq_ssc_transfer_one;
+ master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_CS_HIGH |
+ SPI_LOOP;
+ master->bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 8) |
+ SPI_BPW_MASK(16) | SPI_BPW_MASK(32);
+
+ spi->wq = alloc_ordered_workqueue(dev_name(dev), 0);
+ if (!spi->wq) {
+ err = -ENOMEM;
+ goto err_clk_put;
+ }
+ INIT_WORK(&spi->work, lantiq_ssc_bussy_work);
+
+ id = lantiq_ssc_readl(spi, SPI_ID);
+ spi->tx_fifo_size = (id & SPI_ID_TXFS_M) >> SPI_ID_TXFS_S;
+ spi->rx_fifo_size = (id & SPI_ID_RXFS_M) >> SPI_ID_RXFS_S;
+ supports_dma = (id & SPI_ID_CFG_M) >> SPI_ID_CFG_S;
+ revision = id & SPI_ID_REV_M;
+
+ lantiq_ssc_hw_init(spi);
+
+ dev_info(dev,
+ "Lantiq SSC SPI controller (Rev %i, TXFS %u, RXFS %u, DMA %u)\n",
+ revision, spi->tx_fifo_size, spi->rx_fifo_size, supports_dma);
+
+ err = devm_spi_register_master(dev, master);
+ if (err) {
+ dev_err(dev, "failed to register spi_master\n");
+ goto err_wq_destroy;
+ }
+
+ return 0;
+
+err_wq_destroy:
+ destroy_workqueue(spi->wq);
+err_clk_put:
+ clk_put(spi->fpi_clk);
+err_clk_disable:
+ clk_disable_unprepare(spi->spi_clk);
+err_master_put:
+ spi_master_put(master);
+
+ return err;
+}
+
+static int lantiq_ssc_remove(struct platform_device *pdev)
+{
+ struct lantiq_ssc_spi *spi = platform_get_drvdata(pdev);
+
+ lantiq_ssc_writel(spi, 0, SPI_IRNEN);
+ lantiq_ssc_writel(spi, 0, SPI_CLC);
+ rx_fifo_flush(spi);
+ tx_fifo_flush(spi);
+ hw_enter_config_mode(spi);
+
+ destroy_workqueue(spi->wq);
+ clk_disable_unprepare(spi->spi_clk);
+ clk_put(spi->fpi_clk);
+
+ return 0;
+}
+
+static struct platform_driver lantiq_ssc_driver = {
+ .probe = lantiq_ssc_probe,
+ .remove = lantiq_ssc_remove,
+ .driver = {
+ .name = "spi-lantiq-ssc",
+ .owner = THIS_MODULE,
+ .of_match_table = lantiq_ssc_match,
+ },
+};
+module_platform_driver(lantiq_ssc_driver);
+
+MODULE_DESCRIPTION("Lantiq SSC SPI controller driver");
+MODULE_AUTHOR("Daniel Schwierzeck <daniel.schwierzeck@gmail.com>");
+MODULE_AUTHOR("Hauke Mehrtens <hauke@hauke-m.de>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:spi-lantiq-ssc");
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