linux/drivers/spi/spi-dw-core.c
Andy Shevchenko 27b6965ccb
spi: dw: Propagate firmware node
Propagate firmware node by using a specific API call, i.e. device_set_node().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Serge Semin <fancer.lancer@gmail.com>
Acked-by: Serge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20211222155739.7699-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2021-12-23 13:38:39 +00:00

1011 lines
27 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Designware SPI core controller driver (refer pxa2xx_spi.c)
*
* Copyright (c) 2009, Intel Corporation.
*/
#include <linux/bitfield.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/preempt.h>
#include <linux/highmem.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi-mem.h>
#include <linux/string.h>
#include <linux/of.h>
#include "spi-dw.h"
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>
#endif
/* Slave spi_device related */
struct dw_spi_chip_data {
u32 cr0;
u32 rx_sample_dly; /* RX sample delay */
};
#ifdef CONFIG_DEBUG_FS
#define DW_SPI_DBGFS_REG(_name, _off) \
{ \
.name = _name, \
.offset = _off, \
}
static const struct debugfs_reg32 dw_spi_dbgfs_regs[] = {
DW_SPI_DBGFS_REG("CTRLR0", DW_SPI_CTRLR0),
DW_SPI_DBGFS_REG("CTRLR1", DW_SPI_CTRLR1),
DW_SPI_DBGFS_REG("SSIENR", DW_SPI_SSIENR),
DW_SPI_DBGFS_REG("SER", DW_SPI_SER),
DW_SPI_DBGFS_REG("BAUDR", DW_SPI_BAUDR),
DW_SPI_DBGFS_REG("TXFTLR", DW_SPI_TXFTLR),
DW_SPI_DBGFS_REG("RXFTLR", DW_SPI_RXFTLR),
DW_SPI_DBGFS_REG("TXFLR", DW_SPI_TXFLR),
DW_SPI_DBGFS_REG("RXFLR", DW_SPI_RXFLR),
DW_SPI_DBGFS_REG("SR", DW_SPI_SR),
DW_SPI_DBGFS_REG("IMR", DW_SPI_IMR),
DW_SPI_DBGFS_REG("ISR", DW_SPI_ISR),
DW_SPI_DBGFS_REG("DMACR", DW_SPI_DMACR),
DW_SPI_DBGFS_REG("DMATDLR", DW_SPI_DMATDLR),
DW_SPI_DBGFS_REG("DMARDLR", DW_SPI_DMARDLR),
DW_SPI_DBGFS_REG("RX_SAMPLE_DLY", DW_SPI_RX_SAMPLE_DLY),
};
static int dw_spi_debugfs_init(struct dw_spi *dws)
{
char name[32];
snprintf(name, 32, "dw_spi%d", dws->master->bus_num);
dws->debugfs = debugfs_create_dir(name, NULL);
if (!dws->debugfs)
return -ENOMEM;
dws->regset.regs = dw_spi_dbgfs_regs;
dws->regset.nregs = ARRAY_SIZE(dw_spi_dbgfs_regs);
dws->regset.base = dws->regs;
debugfs_create_regset32("registers", 0400, dws->debugfs, &dws->regset);
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 */
void dw_spi_set_cs(struct spi_device *spi, bool enable)
{
struct dw_spi *dws = spi_controller_get_devdata(spi->controller);
bool cs_high = !!(spi->mode & SPI_CS_HIGH);
/*
* DW SPI controller demands any native CS being set in order to
* proceed with data transfer. So in order to activate the SPI
* communications we must set a corresponding bit in the Slave
* Enable register no matter whether the SPI core is configured to
* support active-high or active-low CS level.
*/
if (cs_high == enable)
dw_writel(dws, DW_SPI_SER, BIT(spi->chip_select));
else
dw_writel(dws, DW_SPI_SER, 0);
}
EXPORT_SYMBOL_NS_GPL(dw_spi_set_cs, SPI_DW_CORE);
/* Return the max entries we can fill into tx fifo */
static inline u32 dw_spi_tx_max(struct dw_spi *dws)
{
u32 tx_room, rxtx_gap;
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->fifo_len - (dws->rx_len - dws->tx_len);
return min3((u32)dws->tx_len, tx_room, rxtx_gap);
}
/* Return the max entries we should read out of rx fifo */
static inline u32 dw_spi_rx_max(struct dw_spi *dws)
{
return min_t(u32, dws->rx_len, dw_readl(dws, DW_SPI_RXFLR));
}
static void dw_writer(struct dw_spi *dws)
{
u32 max = dw_spi_tx_max(dws);
u32 txw = 0;
while (max--) {
if (dws->tx) {
if (dws->n_bytes == 1)
txw = *(u8 *)(dws->tx);
else if (dws->n_bytes == 2)
txw = *(u16 *)(dws->tx);
else
txw = *(u32 *)(dws->tx);
dws->tx += dws->n_bytes;
}
dw_write_io_reg(dws, DW_SPI_DR, txw);
--dws->tx_len;
}
}
static void dw_reader(struct dw_spi *dws)
{
u32 max = dw_spi_rx_max(dws);
u32 rxw;
while (max--) {
rxw = dw_read_io_reg(dws, DW_SPI_DR);
if (dws->rx) {
if (dws->n_bytes == 1)
*(u8 *)(dws->rx) = rxw;
else if (dws->n_bytes == 2)
*(u16 *)(dws->rx) = rxw;
else
*(u32 *)(dws->rx) = rxw;
dws->rx += dws->n_bytes;
}
--dws->rx_len;
}
}
int dw_spi_check_status(struct dw_spi *dws, bool raw)
{
u32 irq_status;
int ret = 0;
if (raw)
irq_status = dw_readl(dws, DW_SPI_RISR);
else
irq_status = dw_readl(dws, DW_SPI_ISR);
if (irq_status & DW_SPI_INT_RXOI) {
dev_err(&dws->master->dev, "RX FIFO overflow detected\n");
ret = -EIO;
}
if (irq_status & DW_SPI_INT_RXUI) {
dev_err(&dws->master->dev, "RX FIFO underflow detected\n");
ret = -EIO;
}
if (irq_status & DW_SPI_INT_TXOI) {
dev_err(&dws->master->dev, "TX FIFO overflow detected\n");
ret = -EIO;
}
/* Generically handle the erroneous situation */
if (ret) {
dw_spi_reset_chip(dws);
if (dws->master->cur_msg)
dws->master->cur_msg->status = ret;
}
return ret;
}
EXPORT_SYMBOL_NS_GPL(dw_spi_check_status, SPI_DW_CORE);
static irqreturn_t dw_spi_transfer_handler(struct dw_spi *dws)
{
u16 irq_status = dw_readl(dws, DW_SPI_ISR);
if (dw_spi_check_status(dws, false)) {
spi_finalize_current_transfer(dws->master);
return IRQ_HANDLED;
}
/*
* Read data from the Rx FIFO every time we've got a chance executing
* this method. If there is nothing left to receive, terminate the
* procedure. Otherwise adjust the Rx FIFO Threshold level if it's a
* final stage of the transfer. By doing so we'll get the next IRQ
* right when the leftover incoming data is received.
*/
dw_reader(dws);
if (!dws->rx_len) {
dw_spi_mask_intr(dws, 0xff);
spi_finalize_current_transfer(dws->master);
} else if (dws->rx_len <= dw_readl(dws, DW_SPI_RXFTLR)) {
dw_writel(dws, DW_SPI_RXFTLR, dws->rx_len - 1);
}
/*
* Send data out if Tx FIFO Empty IRQ is received. The IRQ will be
* disabled after the data transmission is finished so not to
* have the TXE IRQ flood at the final stage of the transfer.
*/
if (irq_status & DW_SPI_INT_TXEI) {
dw_writer(dws);
if (!dws->tx_len)
dw_spi_mask_intr(dws, DW_SPI_INT_TXEI);
}
return IRQ_HANDLED;
}
static irqreturn_t dw_spi_irq(int irq, void *dev_id)
{
struct spi_controller *master = dev_id;
struct dw_spi *dws = spi_controller_get_devdata(master);
u16 irq_status = dw_readl(dws, DW_SPI_ISR) & DW_SPI_INT_MASK;
if (!irq_status)
return IRQ_NONE;
if (!master->cur_msg) {
dw_spi_mask_intr(dws, 0xff);
return IRQ_HANDLED;
}
return dws->transfer_handler(dws);
}
static u32 dw_spi_prepare_cr0(struct dw_spi *dws, struct spi_device *spi)
{
u32 cr0 = 0;
if (dw_spi_ip_is(dws, PSSI)) {
/* CTRLR0[ 5: 4] Frame Format */
cr0 |= FIELD_PREP(DW_PSSI_CTRLR0_FRF_MASK, DW_SPI_CTRLR0_FRF_MOTO_SPI);
/*
* SPI mode (SCPOL|SCPH)
* CTRLR0[ 6] Serial Clock Phase
* CTRLR0[ 7] Serial Clock Polarity
*/
if (spi->mode & SPI_CPOL)
cr0 |= DW_PSSI_CTRLR0_SCPOL;
if (spi->mode & SPI_CPHA)
cr0 |= DW_PSSI_CTRLR0_SCPHA;
/* CTRLR0[11] Shift Register Loop */
if (spi->mode & SPI_LOOP)
cr0 |= DW_PSSI_CTRLR0_SRL;
} else {
/* CTRLR0[ 7: 6] Frame Format */
cr0 |= FIELD_PREP(DW_HSSI_CTRLR0_FRF_MASK, DW_SPI_CTRLR0_FRF_MOTO_SPI);
/*
* SPI mode (SCPOL|SCPH)
* CTRLR0[ 8] Serial Clock Phase
* CTRLR0[ 9] Serial Clock Polarity
*/
if (spi->mode & SPI_CPOL)
cr0 |= DW_HSSI_CTRLR0_SCPOL;
if (spi->mode & SPI_CPHA)
cr0 |= DW_HSSI_CTRLR0_SCPHA;
/* CTRLR0[13] Shift Register Loop */
if (spi->mode & SPI_LOOP)
cr0 |= DW_HSSI_CTRLR0_SRL;
if (dws->caps & DW_SPI_CAP_KEEMBAY_MST)
cr0 |= DW_HSSI_CTRLR0_KEEMBAY_MST;
}
return cr0;
}
void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
struct dw_spi_cfg *cfg)
{
struct dw_spi_chip_data *chip = spi_get_ctldata(spi);
u32 cr0 = chip->cr0;
u32 speed_hz;
u16 clk_div;
/* CTRLR0[ 4/3: 0] or CTRLR0[ 20: 16] Data Frame Size */
cr0 |= (cfg->dfs - 1) << dws->dfs_offset;
if (dw_spi_ip_is(dws, PSSI))
/* CTRLR0[ 9:8] Transfer Mode */
cr0 |= FIELD_PREP(DW_PSSI_CTRLR0_TMOD_MASK, cfg->tmode);
else
/* CTRLR0[11:10] Transfer Mode */
cr0 |= FIELD_PREP(DW_HSSI_CTRLR0_TMOD_MASK, cfg->tmode);
dw_writel(dws, DW_SPI_CTRLR0, cr0);
if (cfg->tmode == DW_SPI_CTRLR0_TMOD_EPROMREAD ||
cfg->tmode == DW_SPI_CTRLR0_TMOD_RO)
dw_writel(dws, DW_SPI_CTRLR1, cfg->ndf ? cfg->ndf - 1 : 0);
/* Note DW APB SSI clock divider doesn't support odd numbers */
clk_div = (DIV_ROUND_UP(dws->max_freq, cfg->freq) + 1) & 0xfffe;
speed_hz = dws->max_freq / clk_div;
if (dws->current_freq != speed_hz) {
dw_spi_set_clk(dws, clk_div);
dws->current_freq = speed_hz;
}
/* Update RX sample delay if required */
if (dws->cur_rx_sample_dly != chip->rx_sample_dly) {
dw_writel(dws, DW_SPI_RX_SAMPLE_DLY, chip->rx_sample_dly);
dws->cur_rx_sample_dly = chip->rx_sample_dly;
}
}
EXPORT_SYMBOL_NS_GPL(dw_spi_update_config, SPI_DW_CORE);
static void dw_spi_irq_setup(struct dw_spi *dws)
{
u16 level;
u8 imask;
/*
* Originally Tx and Rx data lengths match. Rx FIFO Threshold level
* will be adjusted at the final stage of the IRQ-based SPI transfer
* execution so not to lose the leftover of the incoming data.
*/
level = min_t(u16, dws->fifo_len / 2, dws->tx_len);
dw_writel(dws, DW_SPI_TXFTLR, level);
dw_writel(dws, DW_SPI_RXFTLR, level - 1);
dws->transfer_handler = dw_spi_transfer_handler;
imask = DW_SPI_INT_TXEI | DW_SPI_INT_TXOI |
DW_SPI_INT_RXUI | DW_SPI_INT_RXOI | DW_SPI_INT_RXFI;
dw_spi_umask_intr(dws, imask);
}
/*
* The iterative procedure of the poll-based transfer is simple: write as much
* as possible to the Tx FIFO, wait until the pending to receive data is ready
* to be read, read it from the Rx FIFO and check whether the performed
* procedure has been successful.
*
* Note this method the same way as the IRQ-based transfer won't work well for
* the SPI devices connected to the controller with native CS due to the
* automatic CS assertion/de-assertion.
*/
static int dw_spi_poll_transfer(struct dw_spi *dws,
struct spi_transfer *transfer)
{
struct spi_delay delay;
u16 nbits;
int ret;
delay.unit = SPI_DELAY_UNIT_SCK;
nbits = dws->n_bytes * BITS_PER_BYTE;
do {
dw_writer(dws);
delay.value = nbits * (dws->rx_len - dws->tx_len);
spi_delay_exec(&delay, transfer);
dw_reader(dws);
ret = dw_spi_check_status(dws, true);
if (ret)
return ret;
} while (dws->rx_len);
return 0;
}
static int dw_spi_transfer_one(struct spi_controller *master,
struct spi_device *spi,
struct spi_transfer *transfer)
{
struct dw_spi *dws = spi_controller_get_devdata(master);
struct dw_spi_cfg cfg = {
.tmode = DW_SPI_CTRLR0_TMOD_TR,
.dfs = transfer->bits_per_word,
.freq = transfer->speed_hz,
};
int ret;
dws->dma_mapped = 0;
dws->n_bytes = DIV_ROUND_UP(transfer->bits_per_word, BITS_PER_BYTE);
dws->tx = (void *)transfer->tx_buf;
dws->tx_len = transfer->len / dws->n_bytes;
dws->rx = transfer->rx_buf;
dws->rx_len = dws->tx_len;
/* Ensure the data above is visible for all CPUs */
smp_mb();
dw_spi_enable_chip(dws, 0);
dw_spi_update_config(dws, spi, &cfg);
transfer->effective_speed_hz = dws->current_freq;
/* 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 */
dw_spi_mask_intr(dws, 0xff);
if (dws->dma_mapped) {
ret = dws->dma_ops->dma_setup(dws, transfer);
if (ret)
return ret;
}
dw_spi_enable_chip(dws, 1);
if (dws->dma_mapped)
return dws->dma_ops->dma_transfer(dws, transfer);
else if (dws->irq == IRQ_NOTCONNECTED)
return dw_spi_poll_transfer(dws, transfer);
dw_spi_irq_setup(dws);
return 1;
}
static void dw_spi_handle_err(struct spi_controller *master,
struct spi_message *msg)
{
struct dw_spi *dws = spi_controller_get_devdata(master);
if (dws->dma_mapped)
dws->dma_ops->dma_stop(dws);
dw_spi_reset_chip(dws);
}
static int dw_spi_adjust_mem_op_size(struct spi_mem *mem, struct spi_mem_op *op)
{
if (op->data.dir == SPI_MEM_DATA_IN)
op->data.nbytes = clamp_val(op->data.nbytes, 0, DW_SPI_NDF_MASK + 1);
return 0;
}
static bool dw_spi_supports_mem_op(struct spi_mem *mem,
const struct spi_mem_op *op)
{
if (op->data.buswidth > 1 || op->addr.buswidth > 1 ||
op->dummy.buswidth > 1 || op->cmd.buswidth > 1)
return false;
return spi_mem_default_supports_op(mem, op);
}
static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
{
unsigned int i, j, len;
u8 *out;
/*
* Calculate the total length of the EEPROM command transfer and
* either use the pre-allocated buffer or create a temporary one.
*/
len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
if (op->data.dir == SPI_MEM_DATA_OUT)
len += op->data.nbytes;
if (len <= DW_SPI_BUF_SIZE) {
out = dws->buf;
} else {
out = kzalloc(len, GFP_KERNEL);
if (!out)
return -ENOMEM;
}
/*
* Collect the operation code, address and dummy bytes into the single
* buffer. If it's a transfer with data to be sent, also copy it into the
* single buffer in order to speed the data transmission up.
*/
for (i = 0; i < op->cmd.nbytes; ++i)
out[i] = DW_SPI_GET_BYTE(op->cmd.opcode, op->cmd.nbytes - i - 1);
for (j = 0; j < op->addr.nbytes; ++i, ++j)
out[i] = DW_SPI_GET_BYTE(op->addr.val, op->addr.nbytes - j - 1);
for (j = 0; j < op->dummy.nbytes; ++i, ++j)
out[i] = 0x0;
if (op->data.dir == SPI_MEM_DATA_OUT)
memcpy(&out[i], op->data.buf.out, op->data.nbytes);
dws->n_bytes = 1;
dws->tx = out;
dws->tx_len = len;
if (op->data.dir == SPI_MEM_DATA_IN) {
dws->rx = op->data.buf.in;
dws->rx_len = op->data.nbytes;
} else {
dws->rx = NULL;
dws->rx_len = 0;
}
return 0;
}
static void dw_spi_free_mem_buf(struct dw_spi *dws)
{
if (dws->tx != dws->buf)
kfree(dws->tx);
}
static int dw_spi_write_then_read(struct dw_spi *dws, struct spi_device *spi)
{
u32 room, entries, sts;
unsigned int len;
u8 *buf;
/*
* At initial stage we just pre-fill the Tx FIFO in with no rush,
* since native CS hasn't been enabled yet and the automatic data
* transmission won't start til we do that.
*/
len = min(dws->fifo_len, dws->tx_len);
buf = dws->tx;
while (len--)
dw_write_io_reg(dws, DW_SPI_DR, *buf++);
/*
* After setting any bit in the SER register the transmission will
* start automatically. We have to keep up with that procedure
* otherwise the CS de-assertion will happen whereupon the memory
* operation will be pre-terminated.
*/
len = dws->tx_len - ((void *)buf - dws->tx);
dw_spi_set_cs(spi, false);
while (len) {
entries = readl_relaxed(dws->regs + DW_SPI_TXFLR);
if (!entries) {
dev_err(&dws->master->dev, "CS de-assertion on Tx\n");
return -EIO;
}
room = min(dws->fifo_len - entries, len);
for (; room; --room, --len)
dw_write_io_reg(dws, DW_SPI_DR, *buf++);
}
/*
* Data fetching will start automatically if the EEPROM-read mode is
* activated. We have to keep up with the incoming data pace to
* prevent the Rx FIFO overflow causing the inbound data loss.
*/
len = dws->rx_len;
buf = dws->rx;
while (len) {
entries = readl_relaxed(dws->regs + DW_SPI_RXFLR);
if (!entries) {
sts = readl_relaxed(dws->regs + DW_SPI_RISR);
if (sts & DW_SPI_INT_RXOI) {
dev_err(&dws->master->dev, "FIFO overflow on Rx\n");
return -EIO;
}
continue;
}
entries = min(entries, len);
for (; entries; --entries, --len)
*buf++ = dw_read_io_reg(dws, DW_SPI_DR);
}
return 0;
}
static inline bool dw_spi_ctlr_busy(struct dw_spi *dws)
{
return dw_readl(dws, DW_SPI_SR) & DW_SPI_SR_BUSY;
}
static int dw_spi_wait_mem_op_done(struct dw_spi *dws)
{
int retry = DW_SPI_WAIT_RETRIES;
struct spi_delay delay;
unsigned long ns, us;
u32 nents;
nents = dw_readl(dws, DW_SPI_TXFLR);
ns = NSEC_PER_SEC / dws->current_freq * nents;
ns *= dws->n_bytes * BITS_PER_BYTE;
if (ns <= NSEC_PER_USEC) {
delay.unit = SPI_DELAY_UNIT_NSECS;
delay.value = ns;
} else {
us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
delay.unit = SPI_DELAY_UNIT_USECS;
delay.value = clamp_val(us, 0, USHRT_MAX);
}
while (dw_spi_ctlr_busy(dws) && retry--)
spi_delay_exec(&delay, NULL);
if (retry < 0) {
dev_err(&dws->master->dev, "Mem op hanged up\n");
return -EIO;
}
return 0;
}
static void dw_spi_stop_mem_op(struct dw_spi *dws, struct spi_device *spi)
{
dw_spi_enable_chip(dws, 0);
dw_spi_set_cs(spi, true);
dw_spi_enable_chip(dws, 1);
}
/*
* The SPI memory operation implementation below is the best choice for the
* devices, which are selected by the native chip-select lane. It's
* specifically developed to workaround the problem with automatic chip-select
* lane toggle when there is no data in the Tx FIFO buffer. Luckily the current
* SPI-mem core calls exec_op() callback only if the GPIO-based CS is
* unavailable.
*/
static int dw_spi_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
{
struct dw_spi *dws = spi_controller_get_devdata(mem->spi->controller);
struct dw_spi_cfg cfg;
unsigned long flags;
int ret;
/*
* Collect the outbound data into a single buffer to speed the
* transmission up at least on the initial stage.
*/
ret = dw_spi_init_mem_buf(dws, op);
if (ret)
return ret;
/*
* DW SPI EEPROM-read mode is required only for the SPI memory Data-IN
* operation. Transmit-only mode is suitable for the rest of them.
*/
cfg.dfs = 8;
cfg.freq = clamp(mem->spi->max_speed_hz, 0U, dws->max_mem_freq);
if (op->data.dir == SPI_MEM_DATA_IN) {
cfg.tmode = DW_SPI_CTRLR0_TMOD_EPROMREAD;
cfg.ndf = op->data.nbytes;
} else {
cfg.tmode = DW_SPI_CTRLR0_TMOD_TO;
}
dw_spi_enable_chip(dws, 0);
dw_spi_update_config(dws, mem->spi, &cfg);
dw_spi_mask_intr(dws, 0xff);
dw_spi_enable_chip(dws, 1);
/*
* DW APB SSI controller has very nasty peculiarities. First originally
* (without any vendor-specific modifications) it doesn't provide a
* direct way to set and clear the native chip-select signal. Instead
* the controller asserts the CS lane if Tx FIFO isn't empty and a
* transmission is going on, and automatically de-asserts it back to
* the high level if the Tx FIFO doesn't have anything to be pushed
* out. Due to that a multi-tasking or heavy IRQs activity might be
* fatal, since the transfer procedure preemption may cause the Tx FIFO
* getting empty and sudden CS de-assertion, which in the middle of the
* transfer will most likely cause the data loss. Secondly the
* EEPROM-read or Read-only DW SPI transfer modes imply the incoming
* data being automatically pulled in into the Rx FIFO. So if the
* driver software is late in fetching the data from the FIFO before
* it's overflown, new incoming data will be lost. In order to make
* sure the executed memory operations are CS-atomic and to prevent the
* Rx FIFO overflow we have to disable the local interrupts so to block
* any preemption during the subsequent IO operations.
*
* Note. At some circumstances disabling IRQs may not help to prevent
* the problems described above. The CS de-assertion and Rx FIFO
* overflow may still happen due to the relatively slow system bus or
* CPU not working fast enough, so the write-then-read algo implemented
* here just won't keep up with the SPI bus data transfer. Such
* situation is highly platform specific and is supposed to be fixed by
* manually restricting the SPI bus frequency using the
* dws->max_mem_freq parameter.
*/
local_irq_save(flags);
preempt_disable();
ret = dw_spi_write_then_read(dws, mem->spi);
local_irq_restore(flags);
preempt_enable();
/*
* Wait for the operation being finished and check the controller
* status only if there hasn't been any run-time error detected. In the
* former case it's just pointless. In the later one to prevent an
* additional error message printing since any hw error flag being set
* would be due to an error detected on the data transfer.
*/
if (!ret) {
ret = dw_spi_wait_mem_op_done(dws);
if (!ret)
ret = dw_spi_check_status(dws, true);
}
dw_spi_stop_mem_op(dws, mem->spi);
dw_spi_free_mem_buf(dws);
return ret;
}
/*
* Initialize the default memory operations if a glue layer hasn't specified
* custom ones. Direct mapping operations will be preserved anyway since DW SPI
* controller doesn't have an embedded dirmap interface. Note the memory
* operations implemented in this driver is the best choice only for the DW APB
* SSI controller with standard native CS functionality. If a hardware vendor
* has fixed the automatic CS assertion/de-assertion peculiarity, then it will
* be safer to use the normal SPI-messages-based transfers implementation.
*/
static void dw_spi_init_mem_ops(struct dw_spi *dws)
{
if (!dws->mem_ops.exec_op && !(dws->caps & DW_SPI_CAP_CS_OVERRIDE) &&
!dws->set_cs) {
dws->mem_ops.adjust_op_size = dw_spi_adjust_mem_op_size;
dws->mem_ops.supports_op = dw_spi_supports_mem_op;
dws->mem_ops.exec_op = dw_spi_exec_mem_op;
if (!dws->max_mem_freq)
dws->max_mem_freq = dws->max_freq;
}
}
/* This may be called twice for each spi dev */
static int dw_spi_setup(struct spi_device *spi)
{
struct dw_spi *dws = spi_controller_get_devdata(spi->controller);
struct dw_spi_chip_data *chip;
/* Only alloc on first setup */
chip = spi_get_ctldata(spi);
if (!chip) {
struct dw_spi *dws = spi_controller_get_devdata(spi->controller);
u32 rx_sample_dly_ns;
chip = kzalloc(sizeof(*chip), GFP_KERNEL);
if (!chip)
return -ENOMEM;
spi_set_ctldata(spi, chip);
/* Get specific / default rx-sample-delay */
if (device_property_read_u32(&spi->dev,
"rx-sample-delay-ns",
&rx_sample_dly_ns) != 0)
/* Use default controller value */
rx_sample_dly_ns = dws->def_rx_sample_dly_ns;
chip->rx_sample_dly = DIV_ROUND_CLOSEST(rx_sample_dly_ns,
NSEC_PER_SEC /
dws->max_freq);
}
/*
* Update CR0 data each time the setup callback is invoked since
* the device parameters could have been changed, for instance, by
* the MMC SPI driver or something else.
*/
chip->cr0 = dw_spi_prepare_cr0(dws, spi);
return 0;
}
static void dw_spi_cleanup(struct spi_device *spi)
{
struct dw_spi_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 dw_spi_hw_init(struct device *dev, struct dw_spi *dws)
{
dw_spi_reset_chip(dws);
/*
* Retrieve the Synopsys component version if it hasn't been specified
* by the platform. CoreKit version ID is encoded as a 3-chars ASCII
* code enclosed with '*' (typical for the most of Synopsys IP-cores).
*/
if (!dws->ver) {
dws->ver = dw_readl(dws, DW_SPI_VERSION);
dev_dbg(dev, "Synopsys DWC%sSSI v%c.%c%c\n",
dw_spi_ip_is(dws, PSSI) ? " APB " : " ",
DW_SPI_GET_BYTE(dws->ver, 3), DW_SPI_GET_BYTE(dws->ver, 2),
DW_SPI_GET_BYTE(dws->ver, 1));
}
/*
* 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_TXFTLR, fifo);
if (fifo != dw_readl(dws, DW_SPI_TXFTLR))
break;
}
dw_writel(dws, DW_SPI_TXFTLR, 0);
dws->fifo_len = (fifo == 1) ? 0 : fifo;
dev_dbg(dev, "Detected FIFO size: %u bytes\n", dws->fifo_len);
}
/*
* Detect CTRLR0.DFS field size and offset by testing the lowest bits
* writability. Note DWC SSI controller also has the extended DFS, but
* with zero offset.
*/
if (dw_spi_ip_is(dws, PSSI)) {
u32 cr0, tmp = dw_readl(dws, DW_SPI_CTRLR0);
dw_spi_enable_chip(dws, 0);
dw_writel(dws, DW_SPI_CTRLR0, 0xffffffff);
cr0 = dw_readl(dws, DW_SPI_CTRLR0);
dw_writel(dws, DW_SPI_CTRLR0, tmp);
dw_spi_enable_chip(dws, 1);
if (!(cr0 & DW_PSSI_CTRLR0_DFS_MASK)) {
dws->caps |= DW_SPI_CAP_DFS32;
dws->dfs_offset = __bf_shf(DW_PSSI_CTRLR0_DFS32_MASK);
dev_dbg(dev, "Detected 32-bits max data frame size\n");
}
} else {
dws->caps |= DW_SPI_CAP_DFS32;
}
/* enable HW fixup for explicit CS deselect for Amazon's alpine chip */
if (dws->caps & DW_SPI_CAP_CS_OVERRIDE)
dw_writel(dws, DW_SPI_CS_OVERRIDE, 0xF);
}
int dw_spi_add_host(struct device *dev, struct dw_spi *dws)
{
struct spi_controller *master;
int ret;
if (!dws)
return -EINVAL;
master = spi_alloc_master(dev, 0);
if (!master)
return -ENOMEM;
device_set_node(&master->dev, dev_fwnode(dev));
dws->master = master;
dws->dma_addr = (dma_addr_t)(dws->paddr + DW_SPI_DR);
spi_controller_set_devdata(master, dws);
/* Basic HW init */
dw_spi_hw_init(dev, dws);
ret = request_irq(dws->irq, dw_spi_irq, IRQF_SHARED, dev_name(dev),
master);
if (ret < 0 && ret != -ENOTCONN) {
dev_err(dev, "can not get IRQ\n");
goto err_free_master;
}
dw_spi_init_mem_ops(dws);
master->use_gpio_descriptors = true;
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP;
if (dws->caps & DW_SPI_CAP_DFS32)
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
else
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
master->bus_num = dws->bus_num;
master->num_chipselect = dws->num_cs;
master->setup = dw_spi_setup;
master->cleanup = dw_spi_cleanup;
if (dws->set_cs)
master->set_cs = dws->set_cs;
else
master->set_cs = dw_spi_set_cs;
master->transfer_one = dw_spi_transfer_one;
master->handle_err = dw_spi_handle_err;
if (dws->mem_ops.exec_op)
master->mem_ops = &dws->mem_ops;
master->max_speed_hz = dws->max_freq;
master->flags = SPI_MASTER_GPIO_SS;
master->auto_runtime_pm = true;
/* Get default rx sample delay */
device_property_read_u32(dev, "rx-sample-delay-ns",
&dws->def_rx_sample_dly_ns);
if (dws->dma_ops && dws->dma_ops->dma_init) {
ret = dws->dma_ops->dma_init(dev, dws);
if (ret) {
dev_warn(dev, "DMA init failed\n");
} else {
master->can_dma = dws->dma_ops->can_dma;
master->flags |= SPI_CONTROLLER_MUST_TX;
}
}
ret = spi_register_controller(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);
dw_spi_enable_chip(dws, 0);
free_irq(dws->irq, master);
err_free_master:
spi_controller_put(master);
return ret;
}
EXPORT_SYMBOL_NS_GPL(dw_spi_add_host, SPI_DW_CORE);
void dw_spi_remove_host(struct dw_spi *dws)
{
dw_spi_debugfs_remove(dws);
spi_unregister_controller(dws->master);
if (dws->dma_ops && dws->dma_ops->dma_exit)
dws->dma_ops->dma_exit(dws);
dw_spi_shutdown_chip(dws);
free_irq(dws->irq, dws->master);
}
EXPORT_SYMBOL_NS_GPL(dw_spi_remove_host, SPI_DW_CORE);
int dw_spi_suspend_host(struct dw_spi *dws)
{
int ret;
ret = spi_controller_suspend(dws->master);
if (ret)
return ret;
dw_spi_shutdown_chip(dws);
return 0;
}
EXPORT_SYMBOL_NS_GPL(dw_spi_suspend_host, SPI_DW_CORE);
int dw_spi_resume_host(struct dw_spi *dws)
{
dw_spi_hw_init(&dws->master->dev, dws);
return spi_controller_resume(dws->master);
}
EXPORT_SYMBOL_NS_GPL(dw_spi_resume_host, SPI_DW_CORE);
MODULE_AUTHOR("Feng Tang <feng.tang@intel.com>");
MODULE_DESCRIPTION("Driver for DesignWare SPI controller core");
MODULE_LICENSE("GPL v2");