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![Axel Lin](/assets/img/avatar_default.png)
Many drivers that use bitbang library have a leak on probe error paths. This is because once a spi_master_get() call succeeds, we need an additional spi_master_put() call to free the memory. Fix this issue by moving the code taking a reference to master to spi_bitbang_start(), so spi_bitbang_start() will take a reference to master on success. With this change, the caller is responsible for calling spi_bitbang_stop() to decrement the reference and spi_master_put() as counterpart of spi_alloc_master() to prevent a memory leak. So now we have below patten for drivers using bitbang library: probe: spi_alloc_master -> Init reference count to 1 spi_bitbang_start -> Increment reference count remove: spi_bitbang_stop -> Decrement reference count spi_master_put -> Decrement reference count (reference count reaches 0) Fixup all users accordingly. Signed-off-by: Axel Lin <axel.lin@ingics.com> Suggested-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de> Acked-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de> Signed-off-by: Mark Brown <broonie@linaro.org>
195 lines
4.7 KiB
C
195 lines
4.7 KiB
C
/*
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* SH SCI SPI interface
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*
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* Copyright (c) 2008 Magnus Damm
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*
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* Based on S3C24XX GPIO based SPI driver, which is:
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* Copyright (c) 2006 Ben Dooks
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* Copyright (c) 2006 Simtec Electronics
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/delay.h>
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#include <linux/spinlock.h>
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#include <linux/workqueue.h>
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#include <linux/platform_device.h>
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#include <linux/spi/spi.h>
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#include <linux/spi/spi_bitbang.h>
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#include <linux/module.h>
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#include <asm/spi.h>
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#include <asm/io.h>
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struct sh_sci_spi {
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struct spi_bitbang bitbang;
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void __iomem *membase;
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unsigned char val;
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struct sh_spi_info *info;
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struct platform_device *dev;
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};
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#define SCSPTR(sp) (sp->membase + 0x1c)
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#define PIN_SCK (1 << 2)
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#define PIN_TXD (1 << 0)
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#define PIN_RXD PIN_TXD
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#define PIN_INIT ((1 << 1) | (1 << 3) | PIN_SCK | PIN_TXD)
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static inline void setbits(struct sh_sci_spi *sp, int bits, int on)
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{
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/*
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* We are the only user of SCSPTR so no locking is required.
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* Reading bit 2 and 0 in SCSPTR gives pin state as input.
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* Writing the same bits sets the output value.
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* This makes regular read-modify-write difficult so we
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* use sp->val to keep track of the latest register value.
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*/
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if (on)
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sp->val |= bits;
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else
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sp->val &= ~bits;
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iowrite8(sp->val, SCSPTR(sp));
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}
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static inline void setsck(struct spi_device *dev, int on)
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{
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setbits(spi_master_get_devdata(dev->master), PIN_SCK, on);
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}
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static inline void setmosi(struct spi_device *dev, int on)
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{
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setbits(spi_master_get_devdata(dev->master), PIN_TXD, on);
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}
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static inline u32 getmiso(struct spi_device *dev)
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{
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struct sh_sci_spi *sp = spi_master_get_devdata(dev->master);
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return (ioread8(SCSPTR(sp)) & PIN_RXD) ? 1 : 0;
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}
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#define spidelay(x) ndelay(x)
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#include "spi-bitbang-txrx.h"
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static u32 sh_sci_spi_txrx_mode0(struct spi_device *spi,
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unsigned nsecs, u32 word, u8 bits)
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{
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return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
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}
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static u32 sh_sci_spi_txrx_mode1(struct spi_device *spi,
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unsigned nsecs, u32 word, u8 bits)
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{
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return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits);
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}
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static u32 sh_sci_spi_txrx_mode2(struct spi_device *spi,
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unsigned nsecs, u32 word, u8 bits)
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{
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return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits);
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}
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static u32 sh_sci_spi_txrx_mode3(struct spi_device *spi,
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unsigned nsecs, u32 word, u8 bits)
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{
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return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits);
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}
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static void sh_sci_spi_chipselect(struct spi_device *dev, int value)
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{
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struct sh_sci_spi *sp = spi_master_get_devdata(dev->master);
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if (sp->info && sp->info->chip_select)
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(sp->info->chip_select)(sp->info, dev->chip_select, value);
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}
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static int sh_sci_spi_probe(struct platform_device *dev)
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{
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struct resource *r;
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struct spi_master *master;
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struct sh_sci_spi *sp;
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int ret;
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master = spi_alloc_master(&dev->dev, sizeof(struct sh_sci_spi));
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if (master == NULL) {
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dev_err(&dev->dev, "failed to allocate spi master\n");
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ret = -ENOMEM;
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goto err0;
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}
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sp = spi_master_get_devdata(master);
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platform_set_drvdata(dev, sp);
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sp->info = dev_get_platdata(&dev->dev);
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/* setup spi bitbang adaptor */
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sp->bitbang.master = master;
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sp->bitbang.master->bus_num = sp->info->bus_num;
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sp->bitbang.master->num_chipselect = sp->info->num_chipselect;
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sp->bitbang.chipselect = sh_sci_spi_chipselect;
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sp->bitbang.txrx_word[SPI_MODE_0] = sh_sci_spi_txrx_mode0;
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sp->bitbang.txrx_word[SPI_MODE_1] = sh_sci_spi_txrx_mode1;
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sp->bitbang.txrx_word[SPI_MODE_2] = sh_sci_spi_txrx_mode2;
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sp->bitbang.txrx_word[SPI_MODE_3] = sh_sci_spi_txrx_mode3;
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r = platform_get_resource(dev, IORESOURCE_MEM, 0);
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if (r == NULL) {
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ret = -ENOENT;
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goto err1;
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}
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sp->membase = ioremap(r->start, resource_size(r));
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if (!sp->membase) {
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ret = -ENXIO;
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goto err1;
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}
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sp->val = ioread8(SCSPTR(sp));
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setbits(sp, PIN_INIT, 1);
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ret = spi_bitbang_start(&sp->bitbang);
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if (!ret)
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return 0;
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setbits(sp, PIN_INIT, 0);
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iounmap(sp->membase);
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err1:
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spi_master_put(sp->bitbang.master);
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err0:
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return ret;
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}
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static int sh_sci_spi_remove(struct platform_device *dev)
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{
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struct sh_sci_spi *sp = platform_get_drvdata(dev);
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iounmap(sp->membase);
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setbits(sp, PIN_INIT, 0);
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spi_bitbang_stop(&sp->bitbang);
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spi_master_put(sp->bitbang.master);
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return 0;
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}
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static struct platform_driver sh_sci_spi_drv = {
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.probe = sh_sci_spi_probe,
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.remove = sh_sci_spi_remove,
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.driver = {
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.name = "spi_sh_sci",
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.owner = THIS_MODULE,
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},
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};
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module_platform_driver(sh_sci_spi_drv);
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MODULE_DESCRIPTION("SH SCI SPI Driver");
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MODULE_AUTHOR("Magnus Damm <damm@opensource.se>");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:spi_sh_sci");
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