Revision dc280d93623927570da279e99393879dbbab39e7 authored by Thomas Gleixner on 21 December 2016, 19:19:49 UTC, committed by Thomas Gleixner on 25 December 2016, 09:47:42 UTC
Developers manage to overwrite states blindly without thought. That's fatal and hard to debug. Add sanity checks to make it fail. This requries to restructure the code so that the dynamic state allocation happens in the same lock protected section as the actual store. Otherwise the previous assignment of 'Reserved' to the name field would trigger the overwrite check. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Link: http://lkml.kernel.org/r/20161221192111.675234535@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
1 parent 59fefd0
spi-ep93xx.c
/*
* Driver for Cirrus Logic EP93xx SPI controller.
*
* Copyright (C) 2010-2011 Mika Westerberg
*
* Explicit FIFO handling code was inspired by amba-pl022 driver.
*
* Chip select support using other than built-in GPIOs by H. Hartley Sweeten.
*
* For more information about the SPI controller see documentation on Cirrus
* Logic web site:
* http://www.cirrus.com/en/pubs/manual/EP93xx_Users_Guide_UM1.pdf
*
* 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/io.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dmaengine.h>
#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/scatterlist.h>
#include <linux/spi/spi.h>
#include <linux/platform_data/dma-ep93xx.h>
#include <linux/platform_data/spi-ep93xx.h>
#define SSPCR0 0x0000
#define SSPCR0_MODE_SHIFT 6
#define SSPCR0_SCR_SHIFT 8
#define SSPCR1 0x0004
#define SSPCR1_RIE BIT(0)
#define SSPCR1_TIE BIT(1)
#define SSPCR1_RORIE BIT(2)
#define SSPCR1_LBM BIT(3)
#define SSPCR1_SSE BIT(4)
#define SSPCR1_MS BIT(5)
#define SSPCR1_SOD BIT(6)
#define SSPDR 0x0008
#define SSPSR 0x000c
#define SSPSR_TFE BIT(0)
#define SSPSR_TNF BIT(1)
#define SSPSR_RNE BIT(2)
#define SSPSR_RFF BIT(3)
#define SSPSR_BSY BIT(4)
#define SSPCPSR 0x0010
#define SSPIIR 0x0014
#define SSPIIR_RIS BIT(0)
#define SSPIIR_TIS BIT(1)
#define SSPIIR_RORIS BIT(2)
#define SSPICR SSPIIR
/* timeout in milliseconds */
#define SPI_TIMEOUT 5
/* maximum depth of RX/TX FIFO */
#define SPI_FIFO_SIZE 8
/**
* struct ep93xx_spi - EP93xx SPI controller structure
* @pdev: pointer to platform device
* @clk: clock for the controller
* @regs_base: pointer to ioremap()'d registers
* @sspdr_phys: physical address of the SSPDR register
* @wait: wait here until given transfer is completed
* @current_msg: message that is currently processed (or %NULL if none)
* @tx: current byte in transfer to transmit
* @rx: current byte in transfer to receive
* @fifo_level: how full is FIFO (%0..%SPI_FIFO_SIZE - %1). Receiving one
* frame decreases this level and sending one frame increases it.
* @dma_rx: RX DMA channel
* @dma_tx: TX DMA channel
* @dma_rx_data: RX parameters passed to the DMA engine
* @dma_tx_data: TX parameters passed to the DMA engine
* @rx_sgt: sg table for RX transfers
* @tx_sgt: sg table for TX transfers
* @zeropage: dummy page used as RX buffer when only TX buffer is passed in by
* the client
*/
struct ep93xx_spi {
const struct platform_device *pdev;
struct clk *clk;
void __iomem *regs_base;
unsigned long sspdr_phys;
struct completion wait;
struct spi_message *current_msg;
size_t tx;
size_t rx;
size_t fifo_level;
struct dma_chan *dma_rx;
struct dma_chan *dma_tx;
struct ep93xx_dma_data dma_rx_data;
struct ep93xx_dma_data dma_tx_data;
struct sg_table rx_sgt;
struct sg_table tx_sgt;
void *zeropage;
};
/**
* struct ep93xx_spi_chip - SPI device hardware settings
* @spi: back pointer to the SPI device
* @ops: private chip operations
*/
struct ep93xx_spi_chip {
const struct spi_device *spi;
struct ep93xx_spi_chip_ops *ops;
};
/* converts bits per word to CR0.DSS value */
#define bits_per_word_to_dss(bpw) ((bpw) - 1)
static void ep93xx_spi_write_u8(const struct ep93xx_spi *espi,
u16 reg, u8 value)
{
writeb(value, espi->regs_base + reg);
}
static u8 ep93xx_spi_read_u8(const struct ep93xx_spi *spi, u16 reg)
{
return readb(spi->regs_base + reg);
}
static void ep93xx_spi_write_u16(const struct ep93xx_spi *espi,
u16 reg, u16 value)
{
writew(value, espi->regs_base + reg);
}
static u16 ep93xx_spi_read_u16(const struct ep93xx_spi *spi, u16 reg)
{
return readw(spi->regs_base + reg);
}
static int ep93xx_spi_enable(const struct ep93xx_spi *espi)
{
u8 regval;
int err;
err = clk_enable(espi->clk);
if (err)
return err;
regval = ep93xx_spi_read_u8(espi, SSPCR1);
regval |= SSPCR1_SSE;
ep93xx_spi_write_u8(espi, SSPCR1, regval);
return 0;
}
static void ep93xx_spi_disable(const struct ep93xx_spi *espi)
{
u8 regval;
regval = ep93xx_spi_read_u8(espi, SSPCR1);
regval &= ~SSPCR1_SSE;
ep93xx_spi_write_u8(espi, SSPCR1, regval);
clk_disable(espi->clk);
}
static void ep93xx_spi_enable_interrupts(const struct ep93xx_spi *espi)
{
u8 regval;
regval = ep93xx_spi_read_u8(espi, SSPCR1);
regval |= (SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE);
ep93xx_spi_write_u8(espi, SSPCR1, regval);
}
static void ep93xx_spi_disable_interrupts(const struct ep93xx_spi *espi)
{
u8 regval;
regval = ep93xx_spi_read_u8(espi, SSPCR1);
regval &= ~(SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE);
ep93xx_spi_write_u8(espi, SSPCR1, regval);
}
/**
* ep93xx_spi_calc_divisors() - calculates SPI clock divisors
* @espi: ep93xx SPI controller struct
* @rate: desired SPI output clock rate
* @div_cpsr: pointer to return the cpsr (pre-scaler) divider
* @div_scr: pointer to return the scr divider
*/
static int ep93xx_spi_calc_divisors(const struct ep93xx_spi *espi,
u32 rate, u8 *div_cpsr, u8 *div_scr)
{
struct spi_master *master = platform_get_drvdata(espi->pdev);
unsigned long spi_clk_rate = clk_get_rate(espi->clk);
int cpsr, scr;
/*
* Make sure that max value is between values supported by the
* controller. Note that minimum value is already checked in
* ep93xx_spi_transfer_one_message().
*/
rate = clamp(rate, master->min_speed_hz, master->max_speed_hz);
/*
* Calculate divisors so that we can get speed according the
* following formula:
* rate = spi_clock_rate / (cpsr * (1 + scr))
*
* cpsr must be even number and starts from 2, scr can be any number
* between 0 and 255.
*/
for (cpsr = 2; cpsr <= 254; cpsr += 2) {
for (scr = 0; scr <= 255; scr++) {
if ((spi_clk_rate / (cpsr * (scr + 1))) <= rate) {
*div_scr = (u8)scr;
*div_cpsr = (u8)cpsr;
return 0;
}
}
}
return -EINVAL;
}
static void ep93xx_spi_cs_control(struct spi_device *spi, bool control)
{
struct ep93xx_spi_chip *chip = spi_get_ctldata(spi);
int value = (spi->mode & SPI_CS_HIGH) ? control : !control;
if (chip->ops && chip->ops->cs_control)
chip->ops->cs_control(spi, value);
}
/**
* ep93xx_spi_setup() - setup an SPI device
* @spi: SPI device to setup
*
* This function sets up SPI device mode, speed etc. Can be called multiple
* times for a single device. Returns %0 in case of success, negative error in
* case of failure. When this function returns success, the device is
* deselected.
*/
static int ep93xx_spi_setup(struct spi_device *spi)
{
struct ep93xx_spi *espi = spi_master_get_devdata(spi->master);
struct ep93xx_spi_chip *chip;
chip = spi_get_ctldata(spi);
if (!chip) {
dev_dbg(&espi->pdev->dev, "initial setup for %s\n",
spi->modalias);
chip = kzalloc(sizeof(*chip), GFP_KERNEL);
if (!chip)
return -ENOMEM;
chip->spi = spi;
chip->ops = spi->controller_data;
if (chip->ops && chip->ops->setup) {
int ret = chip->ops->setup(spi);
if (ret) {
kfree(chip);
return ret;
}
}
spi_set_ctldata(spi, chip);
}
ep93xx_spi_cs_control(spi, false);
return 0;
}
/**
* ep93xx_spi_cleanup() - cleans up master controller specific state
* @spi: SPI device to cleanup
*
* This function releases master controller specific state for given @spi
* device.
*/
static void ep93xx_spi_cleanup(struct spi_device *spi)
{
struct ep93xx_spi_chip *chip;
chip = spi_get_ctldata(spi);
if (chip) {
if (chip->ops && chip->ops->cleanup)
chip->ops->cleanup(spi);
spi_set_ctldata(spi, NULL);
kfree(chip);
}
}
/**
* ep93xx_spi_chip_setup() - configures hardware according to given @chip
* @espi: ep93xx SPI controller struct
* @chip: chip specific settings
* @speed_hz: transfer speed
* @bits_per_word: transfer bits_per_word
*/
static int ep93xx_spi_chip_setup(const struct ep93xx_spi *espi,
const struct ep93xx_spi_chip *chip,
u32 speed_hz, u8 bits_per_word)
{
u8 dss = bits_per_word_to_dss(bits_per_word);
u8 div_cpsr = 0;
u8 div_scr = 0;
u16 cr0;
int err;
err = ep93xx_spi_calc_divisors(espi, speed_hz, &div_cpsr, &div_scr);
if (err)
return err;
cr0 = div_scr << SSPCR0_SCR_SHIFT;
cr0 |= (chip->spi->mode & (SPI_CPHA|SPI_CPOL)) << SSPCR0_MODE_SHIFT;
cr0 |= dss;
dev_dbg(&espi->pdev->dev, "setup: mode %d, cpsr %d, scr %d, dss %d\n",
chip->spi->mode, div_cpsr, div_scr, dss);
dev_dbg(&espi->pdev->dev, "setup: cr0 %#x\n", cr0);
ep93xx_spi_write_u8(espi, SSPCPSR, div_cpsr);
ep93xx_spi_write_u16(espi, SSPCR0, cr0);
return 0;
}
static void ep93xx_do_write(struct ep93xx_spi *espi, struct spi_transfer *t)
{
if (t->bits_per_word > 8) {
u16 tx_val = 0;
if (t->tx_buf)
tx_val = ((u16 *)t->tx_buf)[espi->tx];
ep93xx_spi_write_u16(espi, SSPDR, tx_val);
espi->tx += sizeof(tx_val);
} else {
u8 tx_val = 0;
if (t->tx_buf)
tx_val = ((u8 *)t->tx_buf)[espi->tx];
ep93xx_spi_write_u8(espi, SSPDR, tx_val);
espi->tx += sizeof(tx_val);
}
}
static void ep93xx_do_read(struct ep93xx_spi *espi, struct spi_transfer *t)
{
if (t->bits_per_word > 8) {
u16 rx_val;
rx_val = ep93xx_spi_read_u16(espi, SSPDR);
if (t->rx_buf)
((u16 *)t->rx_buf)[espi->rx] = rx_val;
espi->rx += sizeof(rx_val);
} else {
u8 rx_val;
rx_val = ep93xx_spi_read_u8(espi, SSPDR);
if (t->rx_buf)
((u8 *)t->rx_buf)[espi->rx] = rx_val;
espi->rx += sizeof(rx_val);
}
}
/**
* ep93xx_spi_read_write() - perform next RX/TX transfer
* @espi: ep93xx SPI controller struct
*
* This function transfers next bytes (or half-words) to/from RX/TX FIFOs. If
* called several times, the whole transfer will be completed. Returns
* %-EINPROGRESS when current transfer was not yet completed otherwise %0.
*
* When this function is finished, RX FIFO should be empty and TX FIFO should be
* full.
*/
static int ep93xx_spi_read_write(struct ep93xx_spi *espi)
{
struct spi_message *msg = espi->current_msg;
struct spi_transfer *t = msg->state;
/* read as long as RX FIFO has frames in it */
while ((ep93xx_spi_read_u8(espi, SSPSR) & SSPSR_RNE)) {
ep93xx_do_read(espi, t);
espi->fifo_level--;
}
/* write as long as TX FIFO has room */
while (espi->fifo_level < SPI_FIFO_SIZE && espi->tx < t->len) {
ep93xx_do_write(espi, t);
espi->fifo_level++;
}
if (espi->rx == t->len)
return 0;
return -EINPROGRESS;
}
static void ep93xx_spi_pio_transfer(struct ep93xx_spi *espi)
{
/*
* Now everything is set up for the current transfer. We prime the TX
* FIFO, enable interrupts, and wait for the transfer to complete.
*/
if (ep93xx_spi_read_write(espi)) {
ep93xx_spi_enable_interrupts(espi);
wait_for_completion(&espi->wait);
}
}
/**
* ep93xx_spi_dma_prepare() - prepares a DMA transfer
* @espi: ep93xx SPI controller struct
* @dir: DMA transfer direction
*
* Function configures the DMA, maps the buffer and prepares the DMA
* descriptor. Returns a valid DMA descriptor in case of success and ERR_PTR
* in case of failure.
*/
static struct dma_async_tx_descriptor *
ep93xx_spi_dma_prepare(struct ep93xx_spi *espi, enum dma_transfer_direction dir)
{
struct spi_transfer *t = espi->current_msg->state;
struct dma_async_tx_descriptor *txd;
enum dma_slave_buswidth buswidth;
struct dma_slave_config conf;
struct scatterlist *sg;
struct sg_table *sgt;
struct dma_chan *chan;
const void *buf, *pbuf;
size_t len = t->len;
int i, ret, nents;
if (t->bits_per_word > 8)
buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
else
buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
memset(&conf, 0, sizeof(conf));
conf.direction = dir;
if (dir == DMA_DEV_TO_MEM) {
chan = espi->dma_rx;
buf = t->rx_buf;
sgt = &espi->rx_sgt;
conf.src_addr = espi->sspdr_phys;
conf.src_addr_width = buswidth;
} else {
chan = espi->dma_tx;
buf = t->tx_buf;
sgt = &espi->tx_sgt;
conf.dst_addr = espi->sspdr_phys;
conf.dst_addr_width = buswidth;
}
ret = dmaengine_slave_config(chan, &conf);
if (ret)
return ERR_PTR(ret);
/*
* We need to split the transfer into PAGE_SIZE'd chunks. This is
* because we are using @espi->zeropage to provide a zero RX buffer
* for the TX transfers and we have only allocated one page for that.
*
* For performance reasons we allocate a new sg_table only when
* needed. Otherwise we will re-use the current one. Eventually the
* last sg_table is released in ep93xx_spi_release_dma().
*/
nents = DIV_ROUND_UP(len, PAGE_SIZE);
if (nents != sgt->nents) {
sg_free_table(sgt);
ret = sg_alloc_table(sgt, nents, GFP_KERNEL);
if (ret)
return ERR_PTR(ret);
}
pbuf = buf;
for_each_sg(sgt->sgl, sg, sgt->nents, i) {
size_t bytes = min_t(size_t, len, PAGE_SIZE);
if (buf) {
sg_set_page(sg, virt_to_page(pbuf), bytes,
offset_in_page(pbuf));
} else {
sg_set_page(sg, virt_to_page(espi->zeropage),
bytes, 0);
}
pbuf += bytes;
len -= bytes;
}
if (WARN_ON(len)) {
dev_warn(&espi->pdev->dev, "len = %zu expected 0!\n", len);
return ERR_PTR(-EINVAL);
}
nents = dma_map_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
if (!nents)
return ERR_PTR(-ENOMEM);
txd = dmaengine_prep_slave_sg(chan, sgt->sgl, nents, dir, DMA_CTRL_ACK);
if (!txd) {
dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
return ERR_PTR(-ENOMEM);
}
return txd;
}
/**
* ep93xx_spi_dma_finish() - finishes with a DMA transfer
* @espi: ep93xx SPI controller struct
* @dir: DMA transfer direction
*
* Function finishes with the DMA transfer. After this, the DMA buffer is
* unmapped.
*/
static void ep93xx_spi_dma_finish(struct ep93xx_spi *espi,
enum dma_transfer_direction dir)
{
struct dma_chan *chan;
struct sg_table *sgt;
if (dir == DMA_DEV_TO_MEM) {
chan = espi->dma_rx;
sgt = &espi->rx_sgt;
} else {
chan = espi->dma_tx;
sgt = &espi->tx_sgt;
}
dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
}
static void ep93xx_spi_dma_callback(void *callback_param)
{
complete(callback_param);
}
static void ep93xx_spi_dma_transfer(struct ep93xx_spi *espi)
{
struct spi_message *msg = espi->current_msg;
struct dma_async_tx_descriptor *rxd, *txd;
rxd = ep93xx_spi_dma_prepare(espi, DMA_DEV_TO_MEM);
if (IS_ERR(rxd)) {
dev_err(&espi->pdev->dev, "DMA RX failed: %ld\n", PTR_ERR(rxd));
msg->status = PTR_ERR(rxd);
return;
}
txd = ep93xx_spi_dma_prepare(espi, DMA_MEM_TO_DEV);
if (IS_ERR(txd)) {
ep93xx_spi_dma_finish(espi, DMA_DEV_TO_MEM);
dev_err(&espi->pdev->dev, "DMA TX failed: %ld\n", PTR_ERR(txd));
msg->status = PTR_ERR(txd);
return;
}
/* We are ready when RX is done */
rxd->callback = ep93xx_spi_dma_callback;
rxd->callback_param = &espi->wait;
/* Now submit both descriptors and wait while they finish */
dmaengine_submit(rxd);
dmaengine_submit(txd);
dma_async_issue_pending(espi->dma_rx);
dma_async_issue_pending(espi->dma_tx);
wait_for_completion(&espi->wait);
ep93xx_spi_dma_finish(espi, DMA_MEM_TO_DEV);
ep93xx_spi_dma_finish(espi, DMA_DEV_TO_MEM);
}
/**
* ep93xx_spi_process_transfer() - processes one SPI transfer
* @espi: ep93xx SPI controller struct
* @msg: current message
* @t: transfer to process
*
* This function processes one SPI transfer given in @t. Function waits until
* transfer is complete (may sleep) and updates @msg->status based on whether
* transfer was successfully processed or not.
*/
static void ep93xx_spi_process_transfer(struct ep93xx_spi *espi,
struct spi_message *msg,
struct spi_transfer *t)
{
struct ep93xx_spi_chip *chip = spi_get_ctldata(msg->spi);
int err;
msg->state = t;
err = ep93xx_spi_chip_setup(espi, chip, t->speed_hz, t->bits_per_word);
if (err) {
dev_err(&espi->pdev->dev,
"failed to setup chip for transfer\n");
msg->status = err;
return;
}
espi->rx = 0;
espi->tx = 0;
/*
* There is no point of setting up DMA for the transfers which will
* fit into the FIFO and can be transferred with a single interrupt.
* So in these cases we will be using PIO and don't bother for DMA.
*/
if (espi->dma_rx && t->len > SPI_FIFO_SIZE)
ep93xx_spi_dma_transfer(espi);
else
ep93xx_spi_pio_transfer(espi);
/*
* In case of error during transmit, we bail out from processing
* the message.
*/
if (msg->status)
return;
msg->actual_length += t->len;
/*
* After this transfer is finished, perform any possible
* post-transfer actions requested by the protocol driver.
*/
if (t->delay_usecs) {
set_current_state(TASK_UNINTERRUPTIBLE);
schedule_timeout(usecs_to_jiffies(t->delay_usecs));
}
if (t->cs_change) {
if (!list_is_last(&t->transfer_list, &msg->transfers)) {
/*
* In case protocol driver is asking us to drop the
* chipselect briefly, we let the scheduler to handle
* any "delay" here.
*/
ep93xx_spi_cs_control(msg->spi, false);
cond_resched();
ep93xx_spi_cs_control(msg->spi, true);
}
}
}
/*
* ep93xx_spi_process_message() - process one SPI message
* @espi: ep93xx SPI controller struct
* @msg: message to process
*
* This function processes a single SPI message. We go through all transfers in
* the message and pass them to ep93xx_spi_process_transfer(). Chipselect is
* asserted during the whole message (unless per transfer cs_change is set).
*
* @msg->status contains %0 in case of success or negative error code in case of
* failure.
*/
static void ep93xx_spi_process_message(struct ep93xx_spi *espi,
struct spi_message *msg)
{
unsigned long timeout;
struct spi_transfer *t;
int err;
/*
* Enable the SPI controller and its clock.
*/
err = ep93xx_spi_enable(espi);
if (err) {
dev_err(&espi->pdev->dev, "failed to enable SPI controller\n");
msg->status = err;
return;
}
/*
* Just to be sure: flush any data from RX FIFO.
*/
timeout = jiffies + msecs_to_jiffies(SPI_TIMEOUT);
while (ep93xx_spi_read_u16(espi, SSPSR) & SSPSR_RNE) {
if (time_after(jiffies, timeout)) {
dev_warn(&espi->pdev->dev,
"timeout while flushing RX FIFO\n");
msg->status = -ETIMEDOUT;
return;
}
ep93xx_spi_read_u16(espi, SSPDR);
}
/*
* We explicitly handle FIFO level. This way we don't have to check TX
* FIFO status using %SSPSR_TNF bit which may cause RX FIFO overruns.
*/
espi->fifo_level = 0;
/*
* Assert the chipselect.
*/
ep93xx_spi_cs_control(msg->spi, true);
list_for_each_entry(t, &msg->transfers, transfer_list) {
ep93xx_spi_process_transfer(espi, msg, t);
if (msg->status)
break;
}
/*
* Now the whole message is transferred (or failed for some reason). We
* deselect the device and disable the SPI controller.
*/
ep93xx_spi_cs_control(msg->spi, false);
ep93xx_spi_disable(espi);
}
static int ep93xx_spi_transfer_one_message(struct spi_master *master,
struct spi_message *msg)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
msg->state = NULL;
msg->status = 0;
msg->actual_length = 0;
espi->current_msg = msg;
ep93xx_spi_process_message(espi, msg);
espi->current_msg = NULL;
spi_finalize_current_message(master);
return 0;
}
static irqreturn_t ep93xx_spi_interrupt(int irq, void *dev_id)
{
struct ep93xx_spi *espi = dev_id;
u8 irq_status = ep93xx_spi_read_u8(espi, SSPIIR);
/*
* If we got ROR (receive overrun) interrupt we know that something is
* wrong. Just abort the message.
*/
if (unlikely(irq_status & SSPIIR_RORIS)) {
/* clear the overrun interrupt */
ep93xx_spi_write_u8(espi, SSPICR, 0);
dev_warn(&espi->pdev->dev,
"receive overrun, aborting the message\n");
espi->current_msg->status = -EIO;
} else {
/*
* Interrupt is either RX (RIS) or TX (TIS). For both cases we
* simply execute next data transfer.
*/
if (ep93xx_spi_read_write(espi)) {
/*
* In normal case, there still is some processing left
* for current transfer. Let's wait for the next
* interrupt then.
*/
return IRQ_HANDLED;
}
}
/*
* Current transfer is finished, either with error or with success. In
* any case we disable interrupts and notify the worker to handle
* any post-processing of the message.
*/
ep93xx_spi_disable_interrupts(espi);
complete(&espi->wait);
return IRQ_HANDLED;
}
static bool ep93xx_spi_dma_filter(struct dma_chan *chan, void *filter_param)
{
if (ep93xx_dma_chan_is_m2p(chan))
return false;
chan->private = filter_param;
return true;
}
static int ep93xx_spi_setup_dma(struct ep93xx_spi *espi)
{
dma_cap_mask_t mask;
int ret;
espi->zeropage = (void *)get_zeroed_page(GFP_KERNEL);
if (!espi->zeropage)
return -ENOMEM;
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
espi->dma_rx_data.port = EP93XX_DMA_SSP;
espi->dma_rx_data.direction = DMA_DEV_TO_MEM;
espi->dma_rx_data.name = "ep93xx-spi-rx";
espi->dma_rx = dma_request_channel(mask, ep93xx_spi_dma_filter,
&espi->dma_rx_data);
if (!espi->dma_rx) {
ret = -ENODEV;
goto fail_free_page;
}
espi->dma_tx_data.port = EP93XX_DMA_SSP;
espi->dma_tx_data.direction = DMA_MEM_TO_DEV;
espi->dma_tx_data.name = "ep93xx-spi-tx";
espi->dma_tx = dma_request_channel(mask, ep93xx_spi_dma_filter,
&espi->dma_tx_data);
if (!espi->dma_tx) {
ret = -ENODEV;
goto fail_release_rx;
}
return 0;
fail_release_rx:
dma_release_channel(espi->dma_rx);
espi->dma_rx = NULL;
fail_free_page:
free_page((unsigned long)espi->zeropage);
return ret;
}
static void ep93xx_spi_release_dma(struct ep93xx_spi *espi)
{
if (espi->dma_rx) {
dma_release_channel(espi->dma_rx);
sg_free_table(&espi->rx_sgt);
}
if (espi->dma_tx) {
dma_release_channel(espi->dma_tx);
sg_free_table(&espi->tx_sgt);
}
if (espi->zeropage)
free_page((unsigned long)espi->zeropage);
}
static int ep93xx_spi_probe(struct platform_device *pdev)
{
struct spi_master *master;
struct ep93xx_spi_info *info;
struct ep93xx_spi *espi;
struct resource *res;
int irq;
int error;
info = dev_get_platdata(&pdev->dev);
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "failed to get irq resources\n");
return -EBUSY;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "unable to get iomem resource\n");
return -ENODEV;
}
master = spi_alloc_master(&pdev->dev, sizeof(*espi));
if (!master)
return -ENOMEM;
master->setup = ep93xx_spi_setup;
master->transfer_one_message = ep93xx_spi_transfer_one_message;
master->cleanup = ep93xx_spi_cleanup;
master->bus_num = pdev->id;
master->num_chipselect = info->num_chipselect;
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
platform_set_drvdata(pdev, master);
espi = spi_master_get_devdata(master);
espi->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(espi->clk)) {
dev_err(&pdev->dev, "unable to get spi clock\n");
error = PTR_ERR(espi->clk);
goto fail_release_master;
}
init_completion(&espi->wait);
/*
* Calculate maximum and minimum supported clock rates
* for the controller.
*/
master->max_speed_hz = clk_get_rate(espi->clk) / 2;
master->min_speed_hz = clk_get_rate(espi->clk) / (254 * 256);
espi->pdev = pdev;
espi->sspdr_phys = res->start + SSPDR;
espi->regs_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(espi->regs_base)) {
error = PTR_ERR(espi->regs_base);
goto fail_release_master;
}
error = devm_request_irq(&pdev->dev, irq, ep93xx_spi_interrupt,
0, "ep93xx-spi", espi);
if (error) {
dev_err(&pdev->dev, "failed to request irq\n");
goto fail_release_master;
}
if (info->use_dma && ep93xx_spi_setup_dma(espi))
dev_warn(&pdev->dev, "DMA setup failed. Falling back to PIO\n");
/* make sure that the hardware is disabled */
ep93xx_spi_write_u8(espi, SSPCR1, 0);
error = devm_spi_register_master(&pdev->dev, master);
if (error) {
dev_err(&pdev->dev, "failed to register SPI master\n");
goto fail_free_dma;
}
dev_info(&pdev->dev, "EP93xx SPI Controller at 0x%08lx irq %d\n",
(unsigned long)res->start, irq);
return 0;
fail_free_dma:
ep93xx_spi_release_dma(espi);
fail_release_master:
spi_master_put(master);
return error;
}
static int ep93xx_spi_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct ep93xx_spi *espi = spi_master_get_devdata(master);
ep93xx_spi_release_dma(espi);
return 0;
}
static struct platform_driver ep93xx_spi_driver = {
.driver = {
.name = "ep93xx-spi",
},
.probe = ep93xx_spi_probe,
.remove = ep93xx_spi_remove,
};
module_platform_driver(ep93xx_spi_driver);
MODULE_DESCRIPTION("EP93xx SPI Controller driver");
MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ep93xx-spi");
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