linux/drivers/mmc/host/sdhci-pltfm.h
Gustavo A. R. Silva 1a91a36aba mmc: Replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20200226223125.GA20630@embeddedor
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
2020-03-24 14:39:45 +01:00

119 lines
3.0 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright 2010 MontaVista Software, LLC.
*
* Author: Anton Vorontsov <avorontsov@ru.mvista.com>
*/
#ifndef _DRIVERS_MMC_SDHCI_PLTFM_H
#define _DRIVERS_MMC_SDHCI_PLTFM_H
#include <linux/clk.h>
#include <linux/platform_device.h>
#include "sdhci.h"
struct sdhci_pltfm_data {
const struct sdhci_ops *ops;
unsigned int quirks;
unsigned int quirks2;
};
struct sdhci_pltfm_host {
struct clk *clk;
/* migrate from sdhci_of_host */
unsigned int clock;
u16 xfer_mode_shadow;
unsigned long private[] ____cacheline_aligned;
};
#ifdef CONFIG_MMC_SDHCI_BIG_ENDIAN_32BIT_BYTE_SWAPPER
/*
* These accessors are designed for big endian hosts doing I/O to
* little endian controllers incorporating a 32-bit hardware byte swapper.
*/
static inline u32 sdhci_be32bs_readl(struct sdhci_host *host, int reg)
{
return in_be32(host->ioaddr + reg);
}
static inline u16 sdhci_be32bs_readw(struct sdhci_host *host, int reg)
{
return in_be16(host->ioaddr + (reg ^ 0x2));
}
static inline u8 sdhci_be32bs_readb(struct sdhci_host *host, int reg)
{
return in_8(host->ioaddr + (reg ^ 0x3));
}
static inline void sdhci_be32bs_writel(struct sdhci_host *host,
u32 val, int reg)
{
out_be32(host->ioaddr + reg, val);
}
static inline void sdhci_be32bs_writew(struct sdhci_host *host,
u16 val, int reg)
{
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
int base = reg & ~0x3;
int shift = (reg & 0x2) * 8;
switch (reg) {
case SDHCI_TRANSFER_MODE:
/*
* Postpone this write, we must do it together with a
* command write that is down below.
*/
pltfm_host->xfer_mode_shadow = val;
return;
case SDHCI_COMMAND:
sdhci_be32bs_writel(host,
val << 16 | pltfm_host->xfer_mode_shadow,
SDHCI_TRANSFER_MODE);
return;
}
clrsetbits_be32(host->ioaddr + base, 0xffff << shift, val << shift);
}
static inline void sdhci_be32bs_writeb(struct sdhci_host *host, u8 val, int reg)
{
int base = reg & ~0x3;
int shift = (reg & 0x3) * 8;
clrsetbits_be32(host->ioaddr + base , 0xff << shift, val << shift);
}
#endif /* CONFIG_MMC_SDHCI_BIG_ENDIAN_32BIT_BYTE_SWAPPER */
void sdhci_get_property(struct platform_device *pdev);
static inline void sdhci_get_of_property(struct platform_device *pdev)
{
return sdhci_get_property(pdev);
}
extern struct sdhci_host *sdhci_pltfm_init(struct platform_device *pdev,
const struct sdhci_pltfm_data *pdata,
size_t priv_size);
extern void sdhci_pltfm_free(struct platform_device *pdev);
extern int sdhci_pltfm_register(struct platform_device *pdev,
const struct sdhci_pltfm_data *pdata,
size_t priv_size);
extern int sdhci_pltfm_unregister(struct platform_device *pdev);
extern unsigned int sdhci_pltfm_clk_get_max_clock(struct sdhci_host *host);
static inline void *sdhci_pltfm_priv(struct sdhci_pltfm_host *host)
{
return host->private;
}
int sdhci_pltfm_suspend(struct device *dev);
int sdhci_pltfm_resume(struct device *dev);
extern const struct dev_pm_ops sdhci_pltfm_pmops;
#endif /* _DRIVERS_MMC_SDHCI_PLTFM_H */