linux-stable/drivers/spi/spi-mt7621.c
Lukas Wunner 46b5c4fb87
spi: mt7621: Don't leak SPI master in probe error path
If the calls to device_reset() or devm_spi_register_controller() fail on
probe of the MediaTek MT7621 SPI driver, the spi_controller struct is
erroneously not freed.  Fix by switching over to the new
devm_spi_alloc_master() helper.

Additionally, there's an ordering issue in mt7621_spi_remove() wherein
the spi_controller is unregistered after disabling the SYS clock.
The correct order is to call spi_unregister_controller() *before* this
teardown step because bus accesses may still be ongoing until that
function returns.

All of these bugs have existed since the driver was first introduced,
so it seems fair to fix them together in a single commit.

Fixes: 1ab7f2a435 ("staging: mt7621-spi: add mt7621 support")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Stefan Roese <sr@denx.de>
Cc: <stable@vger.kernel.org> # v4.17+: 5e844cc37a: spi: Introduce device-managed SPI controller allocation
Cc: <stable@vger.kernel.org> # v4.17+
Link: https://lore.kernel.org/r/72b680796149f5fcda0b3f530ffb7ee73b04f224.1607286887.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2020-12-07 14:18:59 +00:00

421 lines
9.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
//
// spi-mt7621.c -- MediaTek MT7621 SPI controller driver
//
// Copyright (C) 2011 Sergiy <piratfm@gmail.com>
// Copyright (C) 2011-2013 Gabor Juhos <juhosg@openwrt.org>
// Copyright (C) 2014-2015 Felix Fietkau <nbd@nbd.name>
//
// Some parts are based on spi-orion.c:
// Author: Shadi Ammouri <shadi@marvell.com>
// Copyright (C) 2007-2008 Marvell Ltd.
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/reset.h>
#include <linux/spi/spi.h>
#define DRIVER_NAME "spi-mt7621"
/* in usec */
#define RALINK_SPI_WAIT_MAX_LOOP 2000
/* SPISTAT register bit field */
#define SPISTAT_BUSY BIT(0)
#define MT7621_SPI_TRANS 0x00
#define SPITRANS_BUSY BIT(16)
#define MT7621_SPI_OPCODE 0x04
#define MT7621_SPI_DATA0 0x08
#define MT7621_SPI_DATA4 0x18
#define SPI_CTL_TX_RX_CNT_MASK 0xff
#define SPI_CTL_START BIT(8)
#define MT7621_SPI_MASTER 0x28
#define MASTER_MORE_BUFMODE BIT(2)
#define MASTER_FULL_DUPLEX BIT(10)
#define MASTER_RS_CLK_SEL GENMASK(27, 16)
#define MASTER_RS_CLK_SEL_SHIFT 16
#define MASTER_RS_SLAVE_SEL GENMASK(31, 29)
#define MT7621_SPI_MOREBUF 0x2c
#define MT7621_SPI_POLAR 0x38
#define MT7621_SPI_SPACE 0x3c
#define MT7621_CPHA BIT(5)
#define MT7621_CPOL BIT(4)
#define MT7621_LSB_FIRST BIT(3)
struct mt7621_spi {
struct spi_controller *master;
void __iomem *base;
unsigned int sys_freq;
unsigned int speed;
struct clk *clk;
int pending_write;
};
static inline struct mt7621_spi *spidev_to_mt7621_spi(struct spi_device *spi)
{
return spi_controller_get_devdata(spi->master);
}
static inline u32 mt7621_spi_read(struct mt7621_spi *rs, u32 reg)
{
return ioread32(rs->base + reg);
}
static inline void mt7621_spi_write(struct mt7621_spi *rs, u32 reg, u32 val)
{
iowrite32(val, rs->base + reg);
}
static void mt7621_spi_set_cs(struct spi_device *spi, int enable)
{
struct mt7621_spi *rs = spidev_to_mt7621_spi(spi);
int cs = spi->chip_select;
u32 polar = 0;
u32 master;
/*
* Select SPI device 7, enable "more buffer mode" and disable
* full-duplex (only half-duplex really works on this chip
* reliably)
*/
master = mt7621_spi_read(rs, MT7621_SPI_MASTER);
master |= MASTER_RS_SLAVE_SEL | MASTER_MORE_BUFMODE;
master &= ~MASTER_FULL_DUPLEX;
mt7621_spi_write(rs, MT7621_SPI_MASTER, master);
rs->pending_write = 0;
if (enable)
polar = BIT(cs);
mt7621_spi_write(rs, MT7621_SPI_POLAR, polar);
}
static int mt7621_spi_prepare(struct spi_device *spi, unsigned int speed)
{
struct mt7621_spi *rs = spidev_to_mt7621_spi(spi);
u32 rate;
u32 reg;
dev_dbg(&spi->dev, "speed:%u\n", speed);
rate = DIV_ROUND_UP(rs->sys_freq, speed);
dev_dbg(&spi->dev, "rate-1:%u\n", rate);
if (rate > 4097)
return -EINVAL;
if (rate < 2)
rate = 2;
reg = mt7621_spi_read(rs, MT7621_SPI_MASTER);
reg &= ~MASTER_RS_CLK_SEL;
reg |= (rate - 2) << MASTER_RS_CLK_SEL_SHIFT;
rs->speed = speed;
reg &= ~MT7621_LSB_FIRST;
if (spi->mode & SPI_LSB_FIRST)
reg |= MT7621_LSB_FIRST;
/*
* This SPI controller seems to be tested on SPI flash only and some
* bits are swizzled under other SPI modes probably due to incorrect
* wiring inside the silicon. Only mode 0 works correctly.
*/
reg &= ~(MT7621_CPHA | MT7621_CPOL);
mt7621_spi_write(rs, MT7621_SPI_MASTER, reg);
return 0;
}
static inline int mt7621_spi_wait_till_ready(struct mt7621_spi *rs)
{
int i;
for (i = 0; i < RALINK_SPI_WAIT_MAX_LOOP; i++) {
u32 status;
status = mt7621_spi_read(rs, MT7621_SPI_TRANS);
if ((status & SPITRANS_BUSY) == 0)
return 0;
cpu_relax();
udelay(1);
}
return -ETIMEDOUT;
}
static void mt7621_spi_read_half_duplex(struct mt7621_spi *rs,
int rx_len, u8 *buf)
{
int tx_len;
/*
* Combine with any pending write, and perform one or more half-duplex
* transactions reading 'len' bytes. Data to be written is already in
* MT7621_SPI_DATA.
*/
tx_len = rs->pending_write;
rs->pending_write = 0;
while (rx_len || tx_len) {
int i;
u32 val = (min(tx_len, 4) * 8) << 24;
int rx = min(rx_len, 32);
if (tx_len > 4)
val |= (tx_len - 4) * 8;
val |= (rx * 8) << 12;
mt7621_spi_write(rs, MT7621_SPI_MOREBUF, val);
tx_len = 0;
val = mt7621_spi_read(rs, MT7621_SPI_TRANS);
val |= SPI_CTL_START;
mt7621_spi_write(rs, MT7621_SPI_TRANS, val);
mt7621_spi_wait_till_ready(rs);
for (i = 0; i < rx; i++) {
if ((i % 4) == 0)
val = mt7621_spi_read(rs, MT7621_SPI_DATA0 + i);
*buf++ = val & 0xff;
val >>= 8;
}
rx_len -= i;
}
}
static inline void mt7621_spi_flush(struct mt7621_spi *rs)
{
mt7621_spi_read_half_duplex(rs, 0, NULL);
}
static void mt7621_spi_write_half_duplex(struct mt7621_spi *rs,
int tx_len, const u8 *buf)
{
int len = rs->pending_write;
int val = 0;
if (len & 3) {
val = mt7621_spi_read(rs, MT7621_SPI_OPCODE + (len & ~3));
if (len < 4) {
val <<= (4 - len) * 8;
val = swab32(val);
}
}
while (tx_len > 0) {
if (len >= 36) {
rs->pending_write = len;
mt7621_spi_flush(rs);
len = 0;
}
val |= *buf++ << (8 * (len & 3));
len++;
if ((len & 3) == 0) {
if (len == 4)
/* The byte-order of the opcode is weird! */
val = swab32(val);
mt7621_spi_write(rs, MT7621_SPI_OPCODE + len - 4, val);
val = 0;
}
tx_len -= 1;
}
if (len & 3) {
if (len < 4) {
val = swab32(val);
val >>= (4 - len) * 8;
}
mt7621_spi_write(rs, MT7621_SPI_OPCODE + (len & ~3), val);
}
rs->pending_write = len;
}
static int mt7621_spi_transfer_one_message(struct spi_controller *master,
struct spi_message *m)
{
struct mt7621_spi *rs = spi_controller_get_devdata(master);
struct spi_device *spi = m->spi;
unsigned int speed = spi->max_speed_hz;
struct spi_transfer *t = NULL;
int status = 0;
mt7621_spi_wait_till_ready(rs);
list_for_each_entry(t, &m->transfers, transfer_list)
if (t->speed_hz < speed)
speed = t->speed_hz;
if (mt7621_spi_prepare(spi, speed)) {
status = -EIO;
goto msg_done;
}
/* Assert CS */
mt7621_spi_set_cs(spi, 1);
m->actual_length = 0;
list_for_each_entry(t, &m->transfers, transfer_list) {
if ((t->rx_buf) && (t->tx_buf)) {
/*
* This controller will shift some extra data out
* of spi_opcode if (mosi_bit_cnt > 0) &&
* (cmd_bit_cnt == 0). So the claimed full-duplex
* support is broken since we have no way to read
* the MISO value during that bit.
*/
status = -EIO;
goto msg_done;
} else if (t->rx_buf) {
mt7621_spi_read_half_duplex(rs, t->len, t->rx_buf);
} else if (t->tx_buf) {
mt7621_spi_write_half_duplex(rs, t->len, t->tx_buf);
}
m->actual_length += t->len;
}
/* Flush data and deassert CS */
mt7621_spi_flush(rs);
mt7621_spi_set_cs(spi, 0);
msg_done:
m->status = status;
spi_finalize_current_message(master);
return 0;
}
static int mt7621_spi_setup(struct spi_device *spi)
{
struct mt7621_spi *rs = spidev_to_mt7621_spi(spi);
if ((spi->max_speed_hz == 0) ||
(spi->max_speed_hz > (rs->sys_freq / 2)))
spi->max_speed_hz = rs->sys_freq / 2;
if (spi->max_speed_hz < (rs->sys_freq / 4097)) {
dev_err(&spi->dev, "setup: requested speed is too low %d Hz\n",
spi->max_speed_hz);
return -EINVAL;
}
return 0;
}
static const struct of_device_id mt7621_spi_match[] = {
{ .compatible = "ralink,mt7621-spi" },
{},
};
MODULE_DEVICE_TABLE(of, mt7621_spi_match);
static int mt7621_spi_probe(struct platform_device *pdev)
{
const struct of_device_id *match;
struct spi_controller *master;
struct mt7621_spi *rs;
void __iomem *base;
int status = 0;
struct clk *clk;
int ret;
match = of_match_device(mt7621_spi_match, &pdev->dev);
if (!match)
return -EINVAL;
base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(base))
return PTR_ERR(base);
clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(clk)) {
dev_err(&pdev->dev, "unable to get SYS clock, err=%d\n",
status);
return PTR_ERR(clk);
}
status = clk_prepare_enable(clk);
if (status)
return status;
master = devm_spi_alloc_master(&pdev->dev, sizeof(*rs));
if (!master) {
dev_info(&pdev->dev, "master allocation failed\n");
clk_disable_unprepare(clk);
return -ENOMEM;
}
master->mode_bits = SPI_LSB_FIRST;
master->flags = SPI_CONTROLLER_HALF_DUPLEX;
master->setup = mt7621_spi_setup;
master->transfer_one_message = mt7621_spi_transfer_one_message;
master->bits_per_word_mask = SPI_BPW_MASK(8);
master->dev.of_node = pdev->dev.of_node;
master->num_chipselect = 2;
dev_set_drvdata(&pdev->dev, master);
rs = spi_controller_get_devdata(master);
rs->base = base;
rs->clk = clk;
rs->master = master;
rs->sys_freq = clk_get_rate(rs->clk);
rs->pending_write = 0;
dev_info(&pdev->dev, "sys_freq: %u\n", rs->sys_freq);
ret = device_reset(&pdev->dev);
if (ret) {
dev_err(&pdev->dev, "SPI reset failed!\n");
clk_disable_unprepare(clk);
return ret;
}
ret = spi_register_controller(master);
if (ret)
clk_disable_unprepare(clk);
return ret;
}
static int mt7621_spi_remove(struct platform_device *pdev)
{
struct spi_controller *master;
struct mt7621_spi *rs;
master = dev_get_drvdata(&pdev->dev);
rs = spi_controller_get_devdata(master);
spi_unregister_controller(master);
clk_disable_unprepare(rs->clk);
return 0;
}
MODULE_ALIAS("platform:" DRIVER_NAME);
static struct platform_driver mt7621_spi_driver = {
.driver = {
.name = DRIVER_NAME,
.of_match_table = mt7621_spi_match,
},
.probe = mt7621_spi_probe,
.remove = mt7621_spi_remove,
};
module_platform_driver(mt7621_spi_driver);
MODULE_DESCRIPTION("MT7621 SPI driver");
MODULE_AUTHOR("Felix Fietkau <nbd@nbd.name>");
MODULE_LICENSE("GPL");