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-sh-sci.c
/*
* SH SCI SPI interface
*
* Copyright (c) 2008 Magnus Damm
*
* Based on S3C24XX GPIO based SPI driver, which is:
* Copyright (c) 2006 Ben Dooks
* Copyright (c) 2006 Simtec Electronics
*
* 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/kernel.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/module.h>
#include <asm/spi.h>
#include <asm/io.h>
struct sh_sci_spi {
struct spi_bitbang bitbang;
void __iomem *membase;
unsigned char val;
struct sh_spi_info *info;
struct platform_device *dev;
};
#define SCSPTR(sp) (sp->membase + 0x1c)
#define PIN_SCK (1 << 2)
#define PIN_TXD (1 << 0)
#define PIN_RXD PIN_TXD
#define PIN_INIT ((1 << 1) | (1 << 3) | PIN_SCK | PIN_TXD)
static inline void setbits(struct sh_sci_spi *sp, int bits, int on)
{
/*
* We are the only user of SCSPTR so no locking is required.
* Reading bit 2 and 0 in SCSPTR gives pin state as input.
* Writing the same bits sets the output value.
* This makes regular read-modify-write difficult so we
* use sp->val to keep track of the latest register value.
*/
if (on)
sp->val |= bits;
else
sp->val &= ~bits;
iowrite8(sp->val, SCSPTR(sp));
}
static inline void setsck(struct spi_device *dev, int on)
{
setbits(spi_master_get_devdata(dev->master), PIN_SCK, on);
}
static inline void setmosi(struct spi_device *dev, int on)
{
setbits(spi_master_get_devdata(dev->master), PIN_TXD, on);
}
static inline u32 getmiso(struct spi_device *dev)
{
struct sh_sci_spi *sp = spi_master_get_devdata(dev->master);
return (ioread8(SCSPTR(sp)) & PIN_RXD) ? 1 : 0;
}
#define spidelay(x) ndelay(x)
#include "spi-bitbang-txrx.h"
static u32 sh_sci_spi_txrx_mode0(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
}
static u32 sh_sci_spi_txrx_mode1(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits);
}
static u32 sh_sci_spi_txrx_mode2(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits);
}
static u32 sh_sci_spi_txrx_mode3(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits);
}
static void sh_sci_spi_chipselect(struct spi_device *dev, int value)
{
struct sh_sci_spi *sp = spi_master_get_devdata(dev->master);
if (sp->info->chip_select)
(sp->info->chip_select)(sp->info, dev->chip_select, value);
}
static int sh_sci_spi_probe(struct platform_device *dev)
{
struct resource *r;
struct spi_master *master;
struct sh_sci_spi *sp;
int ret;
master = spi_alloc_master(&dev->dev, sizeof(struct sh_sci_spi));
if (master == NULL) {
dev_err(&dev->dev, "failed to allocate spi master\n");
ret = -ENOMEM;
goto err0;
}
sp = spi_master_get_devdata(master);
platform_set_drvdata(dev, sp);
sp->info = dev_get_platdata(&dev->dev);
if (!sp->info) {
dev_err(&dev->dev, "platform data is missing\n");
ret = -ENOENT;
goto err1;
}
/* setup spi bitbang adaptor */
sp->bitbang.master = master;
sp->bitbang.master->bus_num = sp->info->bus_num;
sp->bitbang.master->num_chipselect = sp->info->num_chipselect;
sp->bitbang.chipselect = sh_sci_spi_chipselect;
sp->bitbang.txrx_word[SPI_MODE_0] = sh_sci_spi_txrx_mode0;
sp->bitbang.txrx_word[SPI_MODE_1] = sh_sci_spi_txrx_mode1;
sp->bitbang.txrx_word[SPI_MODE_2] = sh_sci_spi_txrx_mode2;
sp->bitbang.txrx_word[SPI_MODE_3] = sh_sci_spi_txrx_mode3;
r = platform_get_resource(dev, IORESOURCE_MEM, 0);
if (r == NULL) {
ret = -ENOENT;
goto err1;
}
sp->membase = ioremap(r->start, resource_size(r));
if (!sp->membase) {
ret = -ENXIO;
goto err1;
}
sp->val = ioread8(SCSPTR(sp));
setbits(sp, PIN_INIT, 1);
ret = spi_bitbang_start(&sp->bitbang);
if (!ret)
return 0;
setbits(sp, PIN_INIT, 0);
iounmap(sp->membase);
err1:
spi_master_put(sp->bitbang.master);
err0:
return ret;
}
static int sh_sci_spi_remove(struct platform_device *dev)
{
struct sh_sci_spi *sp = platform_get_drvdata(dev);
spi_bitbang_stop(&sp->bitbang);
setbits(sp, PIN_INIT, 0);
iounmap(sp->membase);
spi_master_put(sp->bitbang.master);
return 0;
}
static struct platform_driver sh_sci_spi_drv = {
.probe = sh_sci_spi_probe,
.remove = sh_sci_spi_remove,
.driver = {
.name = "spi_sh_sci",
},
};
module_platform_driver(sh_sci_spi_drv);
MODULE_DESCRIPTION("SH SCI SPI Driver");
MODULE_AUTHOR("Magnus Damm <damm@opensource.se>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:spi_sh_sci");
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