diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-11-07 09:41:06 +0900 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-11-07 09:41:06 +0900 |
commit | 1071ec7bc2dabd0a9d12a1ae5570f4fd3ba944ca (patch) | |
tree | 3f889877ae180066a8e682d915680f240fbfd6ec /drivers/misc/eeprom/sunxi_sid.c | |
parent | c287322c3aadf45ee15339bffdbc2e9117b9cc7a (diff) | |
parent | 425792266a40189e0b3fec02cb59a69935d8c58c (diff) |
Merge tag 'char-misc-3.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc patches from Greg KH:
"Here's the big char/misc driver patchset for 3.13-rc1.
Lots of stuff in here, including some new drivers for Intel's "MIC"
co-processor devices, and a new eeprom driver. Other things include
the driver attribute cleanups, extcon driver updates, hyperv updates,
and a raft of other miscellaneous driver fixes.
All of these have been in linux-next for a while"
* tag 'char-misc-3.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (121 commits)
misc: mic: Fixes for randconfig build errors and warnings.
tifm: fix error return code in tifm_7xx1_probe()
w1-gpio: Use devm_* functions
w1-gpio: Detect of_gpio_error for first gpio
uio: Pass pointers to virt_to_page(), not integers
uio: fix memory leak
misc/at24: avoid infinite loop on write()
misc/93xx46: avoid infinite loop on write()
misc: atmel_pwm: add deferred-probing support
mei: wd: host_init propagate error codes from called functions
mei: replace stray pr_debug with dev_dbg
mei: bus: propagate error code returned by mei_me_cl_by_id
mei: mei_cl_link remove duplicated check for open_handle_count
mei: print correct device state during unexpected reset
mei: nfc: fix memory leak in error path
lkdtm: add tests for additional page permissions
lkdtm: adjust recursion size to avoid warnings
lkdtm: isolate stack corruption test
mei: move host_clients_map cleanup to device init
mei: me: downgrade two errors to debug level
...
Diffstat (limited to 'drivers/misc/eeprom/sunxi_sid.c')
-rw-r--r-- | drivers/misc/eeprom/sunxi_sid.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/drivers/misc/eeprom/sunxi_sid.c b/drivers/misc/eeprom/sunxi_sid.c new file mode 100644 index 00000000000..9c34e570430 --- /dev/null +++ b/drivers/misc/eeprom/sunxi_sid.c @@ -0,0 +1,158 @@ +/* + * Copyright (c) 2013 Oliver Schinagl <oliver@schinagl.nl> + * http://www.linux-sunxi.org + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * This driver exposes the Allwinner security ID, efuses exported in byte- + * sized chunks. + */ + +#include <linux/compiler.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/export.h> +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/kobject.h> +#include <linux/module.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/random.h> +#include <linux/slab.h> +#include <linux/stat.h> +#include <linux/sysfs.h> +#include <linux/types.h> + +#define DRV_NAME "sunxi-sid" + +struct sunxi_sid_data { + void __iomem *reg_base; + unsigned int keysize; +}; + +/* We read the entire key, due to a 32 bit read alignment requirement. Since we + * want to return the requested byte, this results in somewhat slower code and + * uses 4 times more reads as needed but keeps code simpler. Since the SID is + * only very rarely probed, this is not really an issue. + */ +static u8 sunxi_sid_read_byte(const struct sunxi_sid_data *sid_data, + const unsigned int offset) +{ + u32 sid_key; + + if (offset >= sid_data->keysize) + return 0; + + sid_key = ioread32be(sid_data->reg_base + round_down(offset, 4)); + sid_key >>= (offset % 4) * 8; + + return sid_key; /* Only return the last byte */ +} + +static ssize_t sid_read(struct file *fd, struct kobject *kobj, + struct bin_attribute *attr, char *buf, + loff_t pos, size_t size) +{ + struct platform_device *pdev; + struct sunxi_sid_data *sid_data; + int i; + + pdev = to_platform_device(kobj_to_dev(kobj)); + sid_data = platform_get_drvdata(pdev); + + if (pos < 0 || pos >= sid_data->keysize) + return 0; + if (size > sid_data->keysize - pos) + size = sid_data->keysize - pos; + + for (i = 0; i < size; i++) + buf[i] = sunxi_sid_read_byte(sid_data, pos + i); + + return i; +} + +static struct bin_attribute sid_bin_attr = { + .attr = { .name = "eeprom", .mode = S_IRUGO, }, + .read = sid_read, +}; + +static int sunxi_sid_remove(struct platform_device *pdev) +{ + device_remove_bin_file(&pdev->dev, &sid_bin_attr); + dev_dbg(&pdev->dev, "driver unloaded\n"); + + return 0; +} + +static const struct of_device_id sunxi_sid_of_match[] = { + { .compatible = "allwinner,sun4i-sid", .data = (void *)16}, + { .compatible = "allwinner,sun7i-a20-sid", .data = (void *)512}, + {/* sentinel */}, +}; +MODULE_DEVICE_TABLE(of, sunxi_sid_of_match); + +static int sunxi_sid_probe(struct platform_device *pdev) +{ + struct sunxi_sid_data *sid_data; + struct resource *res; + const struct of_device_id *of_dev_id; + u8 *entropy; + unsigned int i; + + sid_data = devm_kzalloc(&pdev->dev, sizeof(struct sunxi_sid_data), + GFP_KERNEL); + if (!sid_data) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + sid_data->reg_base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(sid_data->reg_base)) + return PTR_ERR(sid_data->reg_base); + + of_dev_id = of_match_device(sunxi_sid_of_match, &pdev->dev); + if (!of_dev_id) + return -ENODEV; + sid_data->keysize = (int)of_dev_id->data; + + platform_set_drvdata(pdev, sid_data); + + sid_bin_attr.size = sid_data->keysize; + if (device_create_bin_file(&pdev->dev, &sid_bin_attr)) + return -ENODEV; + + entropy = kzalloc(sizeof(u8) * sid_data->keysize, GFP_KERNEL); + for (i = 0; i < sid_data->keysize; i++) + entropy[i] = sunxi_sid_read_byte(sid_data, i); + add_device_randomness(entropy, sid_data->keysize); + kfree(entropy); + + dev_dbg(&pdev->dev, "loaded\n"); + + return 0; +} + +static struct platform_driver sunxi_sid_driver = { + .probe = sunxi_sid_probe, + .remove = sunxi_sid_remove, + .driver = { + .name = DRV_NAME, + .owner = THIS_MODULE, + .of_match_table = sunxi_sid_of_match, + }, +}; +module_platform_driver(sunxi_sid_driver); + +MODULE_AUTHOR("Oliver Schinagl <oliver@schinagl.nl>"); +MODULE_DESCRIPTION("Allwinner sunxi security id driver"); +MODULE_LICENSE("GPL"); |