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linux/drivers/spi/spi-orion.c
Greg Ungerer 9a2d363552 spi: orion: fix potential NULL pointer de-reference 
It's possible that the call to of_match_device() (introduced in commit
df59fa7f ["spi: orion: support armada extended baud rates"]) may return
a NULL if there is no match in the device tree (or perhaps no device tree
at all). Check the return pointer and set the local device data to the
lowest common denominator orion device data if it is NULL.

Reported-by: Karl Beldan <karl.beldan@gmail.com>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
2014-10-22 11:05:54 +01:00

567 lines
13 KiB
C
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/*
* Marvell Orion SPI controller driver
*
* Author: Shadi Ammouri <shadi@marvell.com>
* Copyright (C) 2007-2008 Marvell Ltd.
*
* 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/interrupt.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/clk.h>
#include <linux/sizes.h>
#include <asm/unaligned.h>
#define DRIVER_NAME "orion_spi"
/* Runtime PM autosuspend timeout: PM is fairly light on this driver */
#define SPI_AUTOSUSPEND_TIMEOUT 200
#define ORION_NUM_CHIPSELECTS 1 /* only one slave is supported*/
#define ORION_SPI_WAIT_RDY_MAX_LOOP 2000 /* in usec */
#define ORION_SPI_IF_CTRL_REG 0x00
#define ORION_SPI_IF_CONFIG_REG 0x04
#define ORION_SPI_DATA_OUT_REG 0x08
#define ORION_SPI_DATA_IN_REG 0x0c
#define ORION_SPI_INT_CAUSE_REG 0x10
#define ORION_SPI_MODE_CPOL (1 << 11)
#define ORION_SPI_MODE_CPHA (1 << 12)
#define ORION_SPI_IF_8_16_BIT_MODE (1 << 5)
#define ORION_SPI_CLK_PRESCALE_MASK 0x1F
#define ARMADA_SPI_CLK_PRESCALE_MASK 0xDF
#define ORION_SPI_MODE_MASK (ORION_SPI_MODE_CPOL | \
ORION_SPI_MODE_CPHA)
enum orion_spi_type {
ORION_SPI,
ARMADA_SPI,
};
struct orion_spi_dev {
enum orion_spi_type typ;
unsigned int min_divisor;
unsigned int max_divisor;
u32 prescale_mask;
};
struct orion_spi {
struct spi_master *master;
void __iomem *base;
struct clk *clk;
const struct orion_spi_dev *devdata;
};
static inline void __iomem *spi_reg(struct orion_spi *orion_spi, u32 reg)
{
return orion_spi->base + reg;
}
static inline void
orion_spi_setbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
{
void __iomem *reg_addr = spi_reg(orion_spi, reg);
u32 val;
val = readl(reg_addr);
val |= mask;
writel(val, reg_addr);
}
static inline void
orion_spi_clrbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
{
void __iomem *reg_addr = spi_reg(orion_spi, reg);
u32 val;
val = readl(reg_addr);
val &= ~mask;
writel(val, reg_addr);
}
static int orion_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
{
u32 tclk_hz;
u32 rate;
u32 prescale;
u32 reg;
struct orion_spi *orion_spi;
const struct orion_spi_dev *devdata;
orion_spi = spi_master_get_devdata(spi->master);
devdata = orion_spi->devdata;
tclk_hz = clk_get_rate(orion_spi->clk);
if (devdata->typ == ARMADA_SPI) {
unsigned int clk, spr, sppr, sppr2, err;
unsigned int best_spr, best_sppr, best_err;
best_err = speed;
best_spr = 0;
best_sppr = 0;
/* Iterate over the valid range looking for best fit */
for (sppr = 0; sppr < 8; sppr++) {
sppr2 = 0x1 << sppr;
spr = tclk_hz / sppr2;
spr = DIV_ROUND_UP(spr, speed);
if ((spr == 0) || (spr > 15))
continue;
clk = tclk_hz / (spr * sppr2);
err = speed - clk;
if (err < best_err) {
best_spr = spr;
best_sppr = sppr;
best_err = err;
}
}
if ((best_sppr == 0) && (best_spr == 0))
return -EINVAL;
prescale = ((best_sppr & 0x6) << 5) |
((best_sppr & 0x1) << 4) | best_spr;
} else {
/*
* the supported rates are: 4,6,8...30
* round up as we look for equal or less speed
*/
rate = DIV_ROUND_UP(tclk_hz, speed);
rate = roundup(rate, 2);
/* check if requested speed is too small */
if (rate > 30)
return -EINVAL;
if (rate < 4)
rate = 4;
/* Convert the rate to SPI clock divisor value. */
prescale = 0x10 + rate/2;
}
reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
reg = ((reg & ~devdata->prescale_mask) | prescale);
writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
return 0;
}
static void
orion_spi_mode_set(struct spi_device *spi)
{
u32 reg;
struct orion_spi *orion_spi;
orion_spi = spi_master_get_devdata(spi->master);
reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
reg &= ~ORION_SPI_MODE_MASK;
if (spi->mode & SPI_CPOL)
reg |= ORION_SPI_MODE_CPOL;
if (spi->mode & SPI_CPHA)
reg |= ORION_SPI_MODE_CPHA;
writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
}
/*
* called only when no transfer is active on the bus
*/
static int
orion_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
{
struct orion_spi *orion_spi;
unsigned int speed = spi->max_speed_hz;
unsigned int bits_per_word = spi->bits_per_word;
int rc;
orion_spi = spi_master_get_devdata(spi->master);
if ((t != NULL) && t->speed_hz)
speed = t->speed_hz;
if ((t != NULL) && t->bits_per_word)
bits_per_word = t->bits_per_word;
orion_spi_mode_set(spi);
rc = orion_spi_baudrate_set(spi, speed);
if (rc)
return rc;
if (bits_per_word == 16)
orion_spi_setbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
ORION_SPI_IF_8_16_BIT_MODE);
else
orion_spi_clrbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
ORION_SPI_IF_8_16_BIT_MODE);
return 0;
}
static void orion_spi_set_cs(struct orion_spi *orion_spi, int enable)
{
if (enable)
orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
else
orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
}
static inline int orion_spi_wait_till_ready(struct orion_spi *orion_spi)
{
int i;
for (i = 0; i < ORION_SPI_WAIT_RDY_MAX_LOOP; i++) {
if (readl(spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG)))
return 1;
udelay(1);
}
return -1;
}
static inline int
orion_spi_write_read_8bit(struct spi_device *spi,
const u8 **tx_buf, u8 **rx_buf)
{
void __iomem *tx_reg, *rx_reg, *int_reg;
struct orion_spi *orion_spi;
orion_spi = spi_master_get_devdata(spi->master);
tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
/* clear the interrupt cause register */
writel(0x0, int_reg);
if (tx_buf && *tx_buf)
writel(*(*tx_buf)++, tx_reg);
else
writel(0, tx_reg);
if (orion_spi_wait_till_ready(orion_spi) < 0) {
dev_err(&spi->dev, "TXS timed out\n");
return -1;
}
if (rx_buf && *rx_buf)
*(*rx_buf)++ = readl(rx_reg);
return 1;
}
static inline int
orion_spi_write_read_16bit(struct spi_device *spi,
const u16 **tx_buf, u16 **rx_buf)
{
void __iomem *tx_reg, *rx_reg, *int_reg;
struct orion_spi *orion_spi;
orion_spi = spi_master_get_devdata(spi->master);
tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
/* clear the interrupt cause register */
writel(0x0, int_reg);
if (tx_buf && *tx_buf)
writel(__cpu_to_le16(get_unaligned((*tx_buf)++)), tx_reg);
else
writel(0, tx_reg);
if (orion_spi_wait_till_ready(orion_spi) < 0) {
dev_err(&spi->dev, "TXS timed out\n");
return -1;
}
if (rx_buf && *rx_buf)
put_unaligned(__le16_to_cpu(readl(rx_reg)), (*rx_buf)++);
return 1;
}
static unsigned int
orion_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
{
unsigned int count;
int word_len;
word_len = spi->bits_per_word;
count = xfer->len;
if (word_len == 8) {
const u8 *tx = xfer->tx_buf;
u8 *rx = xfer->rx_buf;
do {
if (orion_spi_write_read_8bit(spi, &tx, &rx) < 0)
goto out;
count--;
} while (count);
} else if (word_len == 16) {
const u16 *tx = xfer->tx_buf;
u16 *rx = xfer->rx_buf;
do {
if (orion_spi_write_read_16bit(spi, &tx, &rx) < 0)
goto out;
count -= 2;
} while (count);
}
out:
return xfer->len - count;
}
static int orion_spi_transfer_one_message(struct spi_master *master,
struct spi_message *m)
{
struct orion_spi *orion_spi = spi_master_get_devdata(master);
struct spi_device *spi = m->spi;
struct spi_transfer *t = NULL;
int par_override = 0;
int status = 0;
int cs_active = 0;
/* Load defaults */
status = orion_spi_setup_transfer(spi, NULL);
if (status < 0)
goto msg_done;
list_for_each_entry(t, &m->transfers, transfer_list) {
if (par_override || t->speed_hz || t->bits_per_word) {
par_override = 1;
status = orion_spi_setup_transfer(spi, t);
if (status < 0)
break;
if (!t->speed_hz && !t->bits_per_word)
par_override = 0;
}
if (!cs_active) {
orion_spi_set_cs(orion_spi, 1);
cs_active = 1;
}
if (t->len)
m->actual_length += orion_spi_write_read(spi, t);
if (t->delay_usecs)
udelay(t->delay_usecs);
if (t->cs_change) {
orion_spi_set_cs(orion_spi, 0);
cs_active = 0;
}
}
msg_done:
if (cs_active)
orion_spi_set_cs(orion_spi, 0);
m->status = status;
spi_finalize_current_message(master);
return 0;
}
static int orion_spi_reset(struct orion_spi *orion_spi)
{
/* Verify that the CS is deasserted */
orion_spi_set_cs(orion_spi, 0);
return 0;
}
static const struct orion_spi_dev orion_spi_dev_data = {
.typ = ORION_SPI,
.min_divisor = 4,
.max_divisor = 30,
.prescale_mask = ORION_SPI_CLK_PRESCALE_MASK,
};
static const struct orion_spi_dev armada_spi_dev_data = {
.typ = ARMADA_SPI,
.min_divisor = 1,
.max_divisor = 1920,
.prescale_mask = ARMADA_SPI_CLK_PRESCALE_MASK,
};
static const struct of_device_id orion_spi_of_match_table[] = {
{ .compatible = "marvell,orion-spi", .data = &orion_spi_dev_data, },
{ .compatible = "marvell,armada-370-spi", .data = &armada_spi_dev_data, },
{}
};
MODULE_DEVICE_TABLE(of, orion_spi_of_match_table);
static int orion_spi_probe(struct platform_device *pdev)
{
const struct of_device_id *of_id;
const struct orion_spi_dev *devdata;
struct spi_master *master;
struct orion_spi *spi;
struct resource *r;
unsigned long tclk_hz;
int status = 0;
master = spi_alloc_master(&pdev->dev, sizeof(*spi));
if (master == NULL) {
dev_dbg(&pdev->dev, "master allocation failed\n");
return -ENOMEM;
}
if (pdev->id != -1)
master->bus_num = pdev->id;
if (pdev->dev.of_node) {
u32 cell_index;
if (!of_property_read_u32(pdev->dev.of_node, "cell-index",
&cell_index))
master->bus_num = cell_index;
}
/* we support only mode 0, and no options */
master->mode_bits = SPI_CPHA | SPI_CPOL;
master->transfer_one_message = orion_spi_transfer_one_message;
master->num_chipselect = ORION_NUM_CHIPSELECTS;
master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
master->auto_runtime_pm = true;
platform_set_drvdata(pdev, master);
spi = spi_master_get_devdata(master);
spi->master = master;
of_id = of_match_device(orion_spi_of_match_table, &pdev->dev);
devdata = (of_id) ? of_id->data : &orion_spi_dev_data;
spi->devdata = devdata;
spi->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(spi->clk)) {
status = PTR_ERR(spi->clk);
goto out;
}
status = clk_prepare_enable(spi->clk);
if (status)
goto out;
tclk_hz = clk_get_rate(spi->clk);
master->max_speed_hz = DIV_ROUND_UP(tclk_hz, devdata->min_divisor);
master->min_speed_hz = DIV_ROUND_UP(tclk_hz, devdata->max_divisor);
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
spi->base = devm_ioremap_resource(&pdev->dev, r);
if (IS_ERR(spi->base)) {
status = PTR_ERR(spi->base);
goto out_rel_clk;
}
pm_runtime_set_active(&pdev->dev);
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
pm_runtime_enable(&pdev->dev);
status = orion_spi_reset(spi);
if (status < 0)
goto out_rel_pm;
pm_runtime_mark_last_busy(&pdev->dev);
pm_runtime_put_autosuspend(&pdev->dev);
master->dev.of_node = pdev->dev.of_node;
status = spi_register_master(master);
if (status < 0)
goto out_rel_pm;
return status;
out_rel_pm:
pm_runtime_disable(&pdev->dev);
out_rel_clk:
clk_disable_unprepare(spi->clk);
out:
spi_master_put(master);
return status;
}
static int orion_spi_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct orion_spi *spi = spi_master_get_devdata(master);
pm_runtime_get_sync(&pdev->dev);
clk_disable_unprepare(spi->clk);
spi_unregister_master(master);
pm_runtime_disable(&pdev->dev);
return 0;
}
MODULE_ALIAS("platform:" DRIVER_NAME);
#ifdef CONFIG_PM_RUNTIME
static int orion_spi_runtime_suspend(struct device *dev)
{
struct spi_master *master = dev_get_drvdata(dev);
struct orion_spi *spi = spi_master_get_devdata(master);
clk_disable_unprepare(spi->clk);
return 0;
}
static int orion_spi_runtime_resume(struct device *dev)
{
struct spi_master *master = dev_get_drvdata(dev);
struct orion_spi *spi = spi_master_get_devdata(master);
return clk_prepare_enable(spi->clk);
}
#endif
static const struct dev_pm_ops orion_spi_pm_ops = {
SET_RUNTIME_PM_OPS(orion_spi_runtime_suspend,
orion_spi_runtime_resume,
NULL)
};
static struct platform_driver orion_spi_driver = {
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
.pm = &orion_spi_pm_ops,
.of_match_table = of_match_ptr(orion_spi_of_match_table),
},
.probe = orion_spi_probe,
.remove = orion_spi_remove,
};
module_platform_driver(orion_spi_driver);
MODULE_DESCRIPTION("Orion SPI driver");
MODULE_AUTHOR("Shadi Ammouri <shadi@marvell.com>");
MODULE_LICENSE("GPL");
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