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linux/drivers/mtd/maps/sa1100-flash.c
Erick Archer 3ef4600f12 mtd: maps: sa1100-flash: Prefer struct_size over open coded arithmetic 
This is an effort to get rid of all multiplications from allocation
functions in order to prevent integer overflows [1][2].

As the "info" variable is a pointer to "struct sa_info" and this
structure ends in a flexible array:

struct sa_info {
	[...]
	struct sa_subdev_info	subdev[];
};

the preferred way in the kernel is to use the struct_size() helper to
do the arithmetic instead of the calculation "size + size * count" in
the kzalloc() function.

This way, the code is more readable and safer.

This code was detected with the help of Coccinelle, and audited and
modified manually.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
Link: https://github.com/KSPP/linux/issues/160 [2]
Signed-off-by: Erick Archer <erick.archer@outlook.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/AS8PR02MB7237AC633B0D1D2EBD3C40E98B392@AS8PR02MB7237.eurprd02.prod.outlook.com
2024-04-09 08:35:37 +02:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Flash memory access on SA11x0 based devices
*
* (C) 2000 Nicolas Pitre <nico@fluxnic.net>
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/concat.h>
#include <mach/hardware.h>
#include <linux/sizes.h>
#include <asm/mach/flash.h>
struct sa_subdev_info {
char name[16];
struct map_info map;
struct mtd_info *mtd;
struct flash_platform_data *plat;
};
struct sa_info {
struct mtd_info *mtd;
int num_subdev;
struct sa_subdev_info subdev[];
};
static DEFINE_SPINLOCK(sa1100_vpp_lock);
static int sa1100_vpp_refcnt;
static void sa1100_set_vpp(struct map_info *map, int on)
{
struct sa_subdev_info *subdev = container_of(map, struct sa_subdev_info, map);
unsigned long flags;
spin_lock_irqsave(&sa1100_vpp_lock, flags);
if (on) {
if (++sa1100_vpp_refcnt == 1) /* first nested 'on' */
subdev->plat->set_vpp(1);
} else {
if (--sa1100_vpp_refcnt == 0) /* last nested 'off' */
subdev->plat->set_vpp(0);
}
spin_unlock_irqrestore(&sa1100_vpp_lock, flags);
}
static void sa1100_destroy_subdev(struct sa_subdev_info *subdev)
{
if (subdev->mtd)
map_destroy(subdev->mtd);
if (subdev->map.virt)
iounmap(subdev->map.virt);
release_mem_region(subdev->map.phys, subdev->map.size);
}
static int sa1100_probe_subdev(struct sa_subdev_info *subdev, struct resource *res)
{
unsigned long phys;
unsigned int size;
int ret;
phys = res->start;
size = res->end - phys + 1;
/*
* Retrieve the bankwidth from the MSC registers.
* We currently only implement CS0 and CS1 here.
*/
switch (phys) {
default:
printk(KERN_WARNING "SA1100 flash: unknown base address "
"0x%08lx, assuming CS0\n", phys);
fallthrough;
case SA1100_CS0_PHYS:
subdev->map.bankwidth = (MSC0 & MSC_RBW) ? 2 : 4;
break;
case SA1100_CS1_PHYS:
subdev->map.bankwidth = ((MSC0 >> 16) & MSC_RBW) ? 2 : 4;
break;
}
if (!request_mem_region(phys, size, subdev->name)) {
ret = -EBUSY;
goto out;
}
if (subdev->plat->set_vpp)
subdev->map.set_vpp = sa1100_set_vpp;
subdev->map.phys = phys;
subdev->map.size = size;
subdev->map.virt = ioremap(phys, size);
if (!subdev->map.virt) {
ret = -ENOMEM;
goto err;
}
simple_map_init(&subdev->map);
/*
* Now let's probe for the actual flash. Do it here since
* specific machine settings might have been set above.
*/
subdev->mtd = do_map_probe(subdev->plat->map_name, &subdev->map);
if (subdev->mtd == NULL) {
ret = -ENXIO;
goto err;
}
printk(KERN_INFO "SA1100 flash: CFI device at 0x%08lx, %uMiB, %d-bit\n",
phys, (unsigned)(subdev->mtd->size >> 20),
subdev->map.bankwidth * 8);
return 0;
err:
sa1100_destroy_subdev(subdev);
out:
return ret;
}
static void sa1100_destroy(struct sa_info *info, struct flash_platform_data *plat)
{
int i;
if (info->mtd) {
mtd_device_unregister(info->mtd);
if (info->mtd != info->subdev[0].mtd)
mtd_concat_destroy(info->mtd);
}
for (i = info->num_subdev - 1; i >= 0; i--)
sa1100_destroy_subdev(&info->subdev[i]);
kfree(info);
if (plat->exit)
plat->exit();
}
static struct sa_info *sa1100_setup_mtd(struct platform_device *pdev,
struct flash_platform_data *plat)
{
struct sa_info *info;
int nr, i, ret = 0;
/*
* Count number of devices.
*/
for (nr = 0; ; nr++)
if (!platform_get_resource(pdev, IORESOURCE_MEM, nr))
break;
if (nr == 0) {
ret = -ENODEV;
goto out;
}
/*
* Allocate the map_info structs in one go.
*/
info = kzalloc(struct_size(info, subdev, nr), GFP_KERNEL);
if (!info) {
ret = -ENOMEM;
goto out;
}
if (plat->init) {
ret = plat->init();
if (ret)
goto err;
}
/*
* Claim and then map the memory regions.
*/
for (i = 0; i < nr; i++) {
struct sa_subdev_info *subdev = &info->subdev[i];
struct resource *res;
res = platform_get_resource(pdev, IORESOURCE_MEM, i);
if (!res)
break;
subdev->map.name = subdev->name;
sprintf(subdev->name, "%s-%d", plat->name, i);
subdev->plat = plat;
ret = sa1100_probe_subdev(subdev, res);
if (ret)
break;
}
info->num_subdev = i;
/*
* ENXIO is special. It means we didn't find a chip when we probed.
*/
if (ret != 0 && !(ret == -ENXIO && info->num_subdev > 0))
goto err;
/*
* If we found one device, don't bother with concat support. If
* we found multiple devices, use concat if we have it available,
* otherwise fail. Either way, it'll be called "sa1100".
*/
if (info->num_subdev == 1) {
strcpy(info->subdev[0].name, plat->name);
info->mtd = info->subdev[0].mtd;
ret = 0;
} else if (info->num_subdev > 1) {
struct mtd_info **cdev;
cdev = kmalloc_array(nr, sizeof(*cdev), GFP_KERNEL);
if (!cdev) {
ret = -ENOMEM;
goto err;
}
/*
* We detected multiple devices. Concatenate them together.
*/
for (i = 0; i < info->num_subdev; i++)
cdev[i] = info->subdev[i].mtd;
info->mtd = mtd_concat_create(cdev, info->num_subdev,
plat->name);
kfree(cdev);
if (info->mtd == NULL) {
ret = -ENXIO;
goto err;
}
}
info->mtd->dev.parent = &pdev->dev;
if (ret == 0)
return info;
err:
sa1100_destroy(info, plat);
out:
return ERR_PTR(ret);
}
static const char * const part_probes[] = { "cmdlinepart", "RedBoot", NULL };
static int sa1100_mtd_probe(struct platform_device *pdev)
{
struct flash_platform_data *plat = dev_get_platdata(&pdev->dev);
struct sa_info *info;
int err;
if (!plat)
return -ENODEV;
info = sa1100_setup_mtd(pdev, plat);
if (IS_ERR(info)) {
err = PTR_ERR(info);
goto out;
}
/*
* Partition selection stuff.
*/
mtd_device_parse_register(info->mtd, part_probes, NULL, plat->parts,
plat->nr_parts);
platform_set_drvdata(pdev, info);
err = 0;
out:
return err;
}
static void sa1100_mtd_remove(struct platform_device *pdev)
{
struct sa_info *info = platform_get_drvdata(pdev);
struct flash_platform_data *plat = dev_get_platdata(&pdev->dev);
sa1100_destroy(info, plat);
}
static struct platform_driver sa1100_mtd_driver = {
.probe = sa1100_mtd_probe,
.remove_new = sa1100_mtd_remove,
.driver = {
.name = "sa1100-mtd",
},
};
module_platform_driver(sa1100_mtd_driver);
MODULE_AUTHOR("Nicolas Pitre");
MODULE_DESCRIPTION("SA1100 CFI map driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:sa1100-mtd");
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