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linux-sg2042/drivers/spi/spi-lantiq-ssc.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2011-2015 Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
* Copyright (C) 2016 Hauke Mehrtens <hauke@hauke-m.de>
*/
#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 LTQ_SPI_RX_IRQ_NAME "spi_rx"
#define LTQ_SPI_TX_IRQ_NAME "spi_tx"
#define LTQ_SPI_ERR_IRQ_NAME "spi_err"
#define LTQ_SPI_FRM_IRQ_NAME "spi_frm"
#define LTQ_SPI_CLC 0x00
#define LTQ_SPI_PISEL 0x04
#define LTQ_SPI_ID 0x08
#define LTQ_SPI_CON 0x10
#define LTQ_SPI_STAT 0x14
#define LTQ_SPI_WHBSTATE 0x18
#define LTQ_SPI_TB 0x20
#define LTQ_SPI_RB 0x24
#define LTQ_SPI_RXFCON 0x30
#define LTQ_SPI_TXFCON 0x34
#define LTQ_SPI_FSTAT 0x38
#define LTQ_SPI_BRT 0x40
#define LTQ_SPI_BRSTAT 0x44
#define LTQ_SPI_SFCON 0x60
#define LTQ_SPI_SFSTAT 0x64
#define LTQ_SPI_GPOCON 0x70
#define LTQ_SPI_GPOSTAT 0x74
#define LTQ_SPI_FPGO 0x78
#define LTQ_SPI_RXREQ 0x80
#define LTQ_SPI_RXCNT 0x84
#define LTQ_SPI_DMACON 0xec
#define LTQ_SPI_IRNEN 0xf4
#define LTQ_SPI_IRNICR 0xf8
#define LTQ_SPI_IRNCR 0xfc
#define LTQ_SPI_CLC_SMC_S 16 /* Clock divider for sleep mode */
#define LTQ_SPI_CLC_SMC_M (0xFF << LTQ_SPI_CLC_SMC_S)
#define LTQ_SPI_CLC_RMC_S 8 /* Clock divider for normal run mode */
#define LTQ_SPI_CLC_RMC_M (0xFF << LTQ_SPI_CLC_RMC_S)
#define LTQ_SPI_CLC_DISS BIT(1) /* Disable status bit */
#define LTQ_SPI_CLC_DISR BIT(0) /* Disable request bit */
#define LTQ_SPI_ID_TXFS_S 24 /* Implemented TX FIFO size */
#define LTQ_SPI_ID_TXFS_M (0x3F << LTQ_SPI_ID_TXFS_S)
#define LTQ_SPI_ID_RXFS_S 16 /* Implemented RX FIFO size */
#define LTQ_SPI_ID_RXFS_M (0x3F << LTQ_SPI_ID_RXFS_S)
#define LTQ_SPI_ID_MOD_S 8 /* Module ID */
#define LTQ_SPI_ID_MOD_M (0xff << LTQ_SPI_ID_MOD_S)
#define LTQ_SPI_ID_CFG_S 5 /* DMA interface support */
#define LTQ_SPI_ID_CFG_M (1 << LTQ_SPI_ID_CFG_S)
#define LTQ_SPI_ID_REV_M 0x1F /* Hardware revision number */
#define LTQ_SPI_CON_BM_S 16 /* Data width selection */
#define LTQ_SPI_CON_BM_M (0x1F << LTQ_SPI_CON_BM_S)
#define LTQ_SPI_CON_EM BIT(24) /* Echo mode */
#define LTQ_SPI_CON_IDLE BIT(23) /* Idle bit value */
#define LTQ_SPI_CON_ENBV BIT(22) /* Enable byte valid control */
#define LTQ_SPI_CON_RUEN BIT(12) /* Receive underflow error enable */
#define LTQ_SPI_CON_TUEN BIT(11) /* Transmit underflow error enable */
#define LTQ_SPI_CON_AEN BIT(10) /* Abort error enable */
#define LTQ_SPI_CON_REN BIT(9) /* Receive overflow error enable */
#define LTQ_SPI_CON_TEN BIT(8) /* Transmit overflow error enable */
#define LTQ_SPI_CON_LB BIT(7) /* Loopback control */
#define LTQ_SPI_CON_PO BIT(6) /* Clock polarity control */
#define LTQ_SPI_CON_PH BIT(5) /* Clock phase control */
#define LTQ_SPI_CON_HB BIT(4) /* Heading control */
#define LTQ_SPI_CON_RXOFF BIT(1) /* Switch receiver off */
#define LTQ_SPI_CON_TXOFF BIT(0) /* Switch transmitter off */
#define LTQ_SPI_STAT_RXBV_S 28
#define LTQ_SPI_STAT_RXBV_M (0x7 << LTQ_SPI_STAT_RXBV_S)
#define LTQ_SPI_STAT_BSY BIT(13) /* Busy flag */
#define LTQ_SPI_STAT_RUE BIT(12) /* Receive underflow error flag */
#define LTQ_SPI_STAT_TUE BIT(11) /* Transmit underflow error flag */
#define LTQ_SPI_STAT_AE BIT(10) /* Abort error flag */
#define LTQ_SPI_STAT_RE BIT(9) /* Receive error flag */
#define LTQ_SPI_STAT_TE BIT(8) /* Transmit error flag */
#define LTQ_SPI_STAT_ME BIT(7) /* Mode error flag */
#define LTQ_SPI_STAT_MS BIT(1) /* Master/slave select bit */
#define LTQ_SPI_STAT_EN BIT(0) /* Enable bit */
#define LTQ_SPI_STAT_ERRORS (LTQ_SPI_STAT_ME | LTQ_SPI_STAT_TE | \
LTQ_SPI_STAT_RE | LTQ_SPI_STAT_AE | \
LTQ_SPI_STAT_TUE | LTQ_SPI_STAT_RUE)
#define LTQ_SPI_WHBSTATE_SETTUE BIT(15) /* Set transmit underflow error flag */
#define LTQ_SPI_WHBSTATE_SETAE BIT(14) /* Set abort error flag */
#define LTQ_SPI_WHBSTATE_SETRE BIT(13) /* Set receive error flag */
#define LTQ_SPI_WHBSTATE_SETTE BIT(12) /* Set transmit error flag */
#define LTQ_SPI_WHBSTATE_CLRTUE BIT(11) /* Clear transmit underflow error flag */
#define LTQ_SPI_WHBSTATE_CLRAE BIT(10) /* Clear abort error flag */
#define LTQ_SPI_WHBSTATE_CLRRE BIT(9) /* Clear receive error flag */
#define LTQ_SPI_WHBSTATE_CLRTE BIT(8) /* Clear transmit error flag */
#define LTQ_SPI_WHBSTATE_SETME BIT(7) /* Set mode error flag */
#define LTQ_SPI_WHBSTATE_CLRME BIT(6) /* Clear mode error flag */
#define LTQ_SPI_WHBSTATE_SETRUE BIT(5) /* Set receive underflow error flag */
#define LTQ_SPI_WHBSTATE_CLRRUE BIT(4) /* Clear receive underflow error flag */
#define LTQ_SPI_WHBSTATE_SETMS BIT(3) /* Set master select bit */
#define LTQ_SPI_WHBSTATE_CLRMS BIT(2) /* Clear master select bit */
#define LTQ_SPI_WHBSTATE_SETEN BIT(1) /* Set enable bit (operational mode) */
#define LTQ_SPI_WHBSTATE_CLREN BIT(0) /* Clear enable bit (config mode */
#define LTQ_SPI_WHBSTATE_CLR_ERRORS (LTQ_SPI_WHBSTATE_CLRRUE | \
LTQ_SPI_WHBSTATE_CLRME | \
LTQ_SPI_WHBSTATE_CLRTE | \
LTQ_SPI_WHBSTATE_CLRRE | \
LTQ_SPI_WHBSTATE_CLRAE | \
LTQ_SPI_WHBSTATE_CLRTUE)
#define LTQ_SPI_RXFCON_RXFITL_S 8 /* FIFO interrupt trigger level */
#define LTQ_SPI_RXFCON_RXFITL_M (0x3F << LTQ_SPI_RXFCON_RXFITL_S)
#define LTQ_SPI_RXFCON_RXFLU BIT(1) /* FIFO flush */
#define LTQ_SPI_RXFCON_RXFEN BIT(0) /* FIFO enable */
#define LTQ_SPI_TXFCON_TXFITL_S 8 /* FIFO interrupt trigger level */
#define LTQ_SPI_TXFCON_TXFITL_M (0x3F << LTQ_SPI_TXFCON_TXFITL_S)
#define LTQ_SPI_TXFCON_TXFLU BIT(1) /* FIFO flush */
#define LTQ_SPI_TXFCON_TXFEN BIT(0) /* FIFO enable */
#define LTQ_SPI_FSTAT_RXFFL_S 0
#define LTQ_SPI_FSTAT_RXFFL_M (0x3f << LTQ_SPI_FSTAT_RXFFL_S)
#define LTQ_SPI_FSTAT_TXFFL_S 8
#define LTQ_SPI_FSTAT_TXFFL_M (0x3f << LTQ_SPI_FSTAT_TXFFL_S)
#define LTQ_SPI_GPOCON_ISCSBN_S 8
#define LTQ_SPI_GPOCON_INVOUTN_S 0
#define LTQ_SPI_FGPO_SETOUTN_S 8
#define LTQ_SPI_FGPO_CLROUTN_S 0
#define LTQ_SPI_RXREQ_RXCNT_M 0xFFFF /* Receive count value */
#define LTQ_SPI_RXCNT_TODO_M 0xFFFF /* Recevie to-do value */
#define LTQ_SPI_IRNEN_TFI BIT(4) /* TX finished interrupt */
#define LTQ_SPI_IRNEN_F BIT(3) /* Frame end interrupt request */
#define LTQ_SPI_IRNEN_E BIT(2) /* Error end interrupt request */
#define LTQ_SPI_IRNEN_T_XWAY BIT(1) /* Transmit end interrupt request */
#define LTQ_SPI_IRNEN_R_XWAY BIT(0) /* Receive end interrupt request */
#define LTQ_SPI_IRNEN_R_XRX BIT(1) /* Transmit end interrupt request */
#define LTQ_SPI_IRNEN_T_XRX BIT(0) /* Receive end interrupt request */
#define LTQ_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, LTQ_SPI_FSTAT);
return (fstat & LTQ_SPI_FSTAT_TXFFL_M) >> LTQ_SPI_FSTAT_TXFFL_S;
}
static unsigned int rx_fifo_level(const struct lantiq_ssc_spi *spi)
{
u32 fstat = lantiq_ssc_readl(spi, LTQ_SPI_FSTAT);
return fstat & LTQ_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 << LTQ_SPI_RXFCON_RXFITL_S;
val |= LTQ_SPI_RXFCON_RXFEN | LTQ_SPI_RXFCON_RXFLU;
lantiq_ssc_writel(spi, val, LTQ_SPI_RXFCON);
}
static void tx_fifo_reset(const struct lantiq_ssc_spi *spi)
{
u32 val = 1 << LTQ_SPI_TXFCON_TXFITL_S;
val |= LTQ_SPI_TXFCON_TXFEN | LTQ_SPI_TXFCON_TXFLU;
lantiq_ssc_writel(spi, val, LTQ_SPI_TXFCON);
}
static void rx_fifo_flush(const struct lantiq_ssc_spi *spi)
{
lantiq_ssc_maskl(spi, 0, LTQ_SPI_RXFCON_RXFLU, LTQ_SPI_RXFCON);
}
static void tx_fifo_flush(const struct lantiq_ssc_spi *spi)
{
lantiq_ssc_maskl(spi, 0, LTQ_SPI_TXFCON_TXFLU, LTQ_SPI_TXFCON);
}
static void hw_enter_config_mode(const struct lantiq_ssc_spi *spi)
{
lantiq_ssc_writel(spi, LTQ_SPI_WHBSTATE_CLREN, LTQ_SPI_WHBSTATE);
}
static void hw_enter_active_mode(const struct lantiq_ssc_spi *spi)
{
lantiq_ssc_writel(spi, LTQ_SPI_WHBSTATE_SETEN, LTQ_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, LTQ_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) << LTQ_SPI_CON_BM_S;
lantiq_ssc_maskl(spi, LTQ_SPI_CON_BM_M, bm, LTQ_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 |= LTQ_SPI_CON_PH;
else
con_set |= LTQ_SPI_CON_PH;
if (mode & SPI_CPOL)
con_set |= LTQ_SPI_CON_PO | LTQ_SPI_CON_IDLE;
else
con_clr |= LTQ_SPI_CON_PO | LTQ_SPI_CON_IDLE;
/* Set heading control */
if (mode & SPI_LSB_FIRST)
con_clr |= LTQ_SPI_CON_HB;
else
con_set |= LTQ_SPI_CON_HB;
/* Set loopback mode */
if (mode & SPI_LOOP)
con_set |= LTQ_SPI_CON_LB;
else
con_clr |= LTQ_SPI_CON_LB;
lantiq_ssc_maskl(spi, con_clr, con_set, LTQ_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 << LTQ_SPI_CLC_RMC_S, LTQ_SPI_CLC);
/* Put controller into config mode */
hw_enter_config_mode(spi);
/* Clear error flags */
lantiq_ssc_maskl(spi, 0, LTQ_SPI_WHBSTATE_CLR_ERRORS, LTQ_SPI_WHBSTATE);
/* Enable error checking, disable TX/RX */
lantiq_ssc_writel(spi, LTQ_SPI_CON_RUEN | LTQ_SPI_CON_AEN |
LTQ_SPI_CON_TEN | LTQ_SPI_CON_REN | LTQ_SPI_CON_TXOFF |
LTQ_SPI_CON_RXOFF, LTQ_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, LTQ_SPI_WHBSTATE_SETMS |
LTQ_SPI_WHBSTATE_CLR_ERRORS,
LTQ_SPI_WHBSTATE);
/* Reset GPIO/CS registers */
lantiq_ssc_writel(spi, 0, LTQ_SPI_GPOCON);
lantiq_ssc_writel(spi, 0xFF00, LTQ_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 |
LTQ_SPI_IRNEN_E, LTQ_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) + LTQ_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, LTQ_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, LTQ_SPI_CON);
if (t->tx_buf)
con &= ~LTQ_SPI_CON_TXOFF;
else
con |= LTQ_SPI_CON_TXOFF;
if (t->rx_buf)
con &= ~LTQ_SPI_CON_RXOFF;
else
con |= LTQ_SPI_CON_RXOFF;
lantiq_ssc_writel(spi, con, LTQ_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, LTQ_SPI_CON_TXOFF | LTQ_SPI_CON_RXOFF,
LTQ_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, LTQ_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, LTQ_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, LTQ_SPI_STAT) &
LTQ_SPI_STAT_RXBV_M) >> LTQ_SPI_STAT_RXBV_S;
data = lantiq_ssc_readl(spi, LTQ_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, LTQ_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, LTQ_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, LTQ_SPI_STAT);
if (!(stat & LTQ_SPI_STAT_ERRORS))
return IRQ_NONE;
if (stat & LTQ_SPI_STAT_RUE)
dev_err(spi->dev, "receive underflow error\n");
if (stat & LTQ_SPI_STAT_TUE)
dev_err(spi->dev, "transmit underflow error\n");
if (stat & LTQ_SPI_STAT_AE)
dev_err(spi->dev, "abort error\n");
if (stat & LTQ_SPI_STAT_RE)
dev_err(spi->dev, "receive overflow error\n");
if (stat & LTQ_SPI_STAT_TE)
dev_err(spi->dev, "transmit overflow error\n");
if (stat & LTQ_SPI_STAT_ME)
dev_err(spi->dev, "mode error\n");
/* Clear error flags */
lantiq_ssc_maskl(spi, 0, LTQ_SPI_WHBSTATE_CLR_ERRORS, LTQ_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, LTQ_SPI_STAT);
if (!(stat & LTQ_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 + LTQ_SPI_FGPO_SETOUTN_S));
lantiq_ssc_writel(spi, fgpo, LTQ_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 = LTQ_SPI_IRNEN_R_XWAY,
.irnen_t = LTQ_SPI_IRNEN_T_XWAY,
};
static const struct lantiq_ssc_hwcfg lantiq_ssc_xrx = {
.irnen_r = LTQ_SPI_IRNEN_R_XRX,
.irnen_t = LTQ_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, LTQ_SPI_RX_IRQ_NAME);
if (rx_irq < 0)
return -ENXIO;
tx_irq = platform_get_irq_byname(pdev, LTQ_SPI_TX_IRQ_NAME);
if (tx_irq < 0)
return -ENXIO;
err_irq = platform_get_irq_byname(pdev, LTQ_SPI_ERR_IRQ_NAME);
if (err_irq < 0)
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, LTQ_SPI_RX_IRQ_NAME, spi);
if (err)
goto err_master_put;
err = devm_request_irq(dev, tx_irq, lantiq_ssc_xmit_interrupt,
0, LTQ_SPI_TX_IRQ_NAME, spi);
if (err)
goto err_master_put;
err = devm_request_irq(dev, err_irq, lantiq_ssc_err_interrupt,
0, LTQ_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, LTQ_SPI_ID);
spi->tx_fifo_size = (id & LTQ_SPI_ID_TXFS_M) >> LTQ_SPI_ID_TXFS_S;
spi->rx_fifo_size = (id & LTQ_SPI_ID_RXFS_M) >> LTQ_SPI_ID_RXFS_S;
supports_dma = (id & LTQ_SPI_ID_CFG_M) >> LTQ_SPI_ID_CFG_S;
revision = id & LTQ_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, LTQ_SPI_IRNEN);
lantiq_ssc_writel(spi, 0, LTQ_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",
.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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