Hi Oliver, On Monday 17 of June 2013 22:59:37 Oliver Schinagl wrote: > From: Oliver Schinagl <[email protected]> > > Allwinner has electric fuses (efuse) on their line of chips. This driver > reads those fuses, seeds the kernel entropy and exports them as a sysfs > node. > > These fuses are most likly to be programmed at the factory, encoding > things like Chip ID, some sort of serial number etc and appear to be > reasonable unique. > While in theory, these should be writeable by the user, it will probably > be inconvinient to do so. Allwinner recommends that a certain input > pin, labeled 'efuse_vddq', be connected to GND. To write these fuses, > 2.5 V needs to be applied to this pin. > > Even so, they can still be used to generate a board-unique mac from, > board unique RSA key and seed the kernel RNG. > > Currently supported are the following known chips: > Allwinner sun4i (A10) > Allwinner sun5i (A10s, A13) > > Signed-off-by: Oliver Schinagl <[email protected]> > --- > drivers/misc/eeprom/Kconfig | 17 +++++ > drivers/misc/eeprom/Makefile | 1 + > drivers/misc/eeprom/sunxi_sid.c | 147 > ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 165 > insertions(+) > create mode 100644 drivers/misc/eeprom/sunxi_sid.c
Looks good to me. Have my Reviewed-by: Tomasz Figa <[email protected]> Best regards, Tomasz > diff --git a/drivers/misc/eeprom/Kconfig b/drivers/misc/eeprom/Kconfig > index 04f2e1f..c7bc6ed 100644 > --- a/drivers/misc/eeprom/Kconfig > +++ b/drivers/misc/eeprom/Kconfig > @@ -96,4 +96,21 @@ config EEPROM_DIGSY_MTC_CFG > > If unsure, say N. > > +config EEPROM_SUNXI_SID > + tristate "Allwinner sunxi security ID support" > + depends on ARCH_SUNXI && SYSFS > + help > + This is a driver for the 'security ID' available on various > Allwinner + devices. Currently supported are: > + sun4i (A10) > + sun5i (A13) > + > + Due to the potential risks involved with changing e-fuses, > + this driver is read-only > + > + For more information visit http://linux-sunxi.org/SID > + > + This driver can also be built as a module. If so, the module > + will be called sunxi_sid. > + > endmenu > diff --git a/drivers/misc/eeprom/Makefile b/drivers/misc/eeprom/Makefile > index fc1e81d..9507aec 100644 > --- a/drivers/misc/eeprom/Makefile > +++ b/drivers/misc/eeprom/Makefile > @@ -4,4 +4,5 @@ obj-$(CONFIG_EEPROM_LEGACY) += eeprom.o > obj-$(CONFIG_EEPROM_MAX6875) += max6875.o > obj-$(CONFIG_EEPROM_93CX6) += eeprom_93cx6.o > obj-$(CONFIG_EEPROM_93XX46) += eeprom_93xx46.o > +obj-$(CONFIG_EEPROM_SUNXI_SID) += sunxi_sid.o > obj-$(CONFIG_EEPROM_DIGSY_MTC_CFG) += digsy_mtc_eeprom.o > diff --git a/drivers/misc/eeprom/sunxi_sid.c > b/drivers/misc/eeprom/sunxi_sid.c new file mode 100644 > index 0000000..6a16c19 > --- /dev/null > +++ b/drivers/misc/eeprom/sunxi_sid.c > @@ -0,0 +1,147 @@ > +/* > + * Copyright (c) 2013 Oliver Schinagl > + * http://www.linux-sunxi.org > + * > + * Oliver Schinagl <[email protected]> > + * > + * 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, a 128 bit eeprom, 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/platform_device.h> > +#include <linux/random.h> > +#include <linux/stat.h> > +#include <linux/sysfs.h> > +#include <linux/types.h> > + > +#define DRV_NAME "sunxi-sid" > + > +/* There are 4 32-bit keys */ > +#define SID_KEYS 4 > +/* Each key is 4 bytes long */ > +#define SID_SIZE (SID_KEYS * 4) > + > +/* We read the entire key, due to a 32 bit read alignment requirement. > Since we + * want to return the requested byte, this resuls in somewhat > slower code and + * uses 4 times more reads as needed but keeps code > simpler. Since the SID is + * only very rarly probed, this is not > really an issue. > + */ > +static u8 sunxi_sid_read_byte(const void __iomem *sid_reg_base, > + const unsigned int offset) > +{ > + u32 sid_key; > + > + if (offset >= SID_SIZE) > + return 0; > + > + sid_key = ioread32be(sid_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) > +{ > + int i; > + struct platform_device *pdev; > + void __iomem *sid_reg_base; > + > + pdev = to_platform_device(kobj_to_dev(kobj)); > + sid_reg_base = (void __iomem *)platform_get_drvdata(pdev); > + > + if (pos < 0 || pos >= SID_SIZE) > + return 0; > + if (size > (SID_SIZE - pos)) > + size = SID_SIZE - pos; > + > + for (i = 0; i < size; i++) > + buf[i] = sunxi_sid_read_byte(sid_reg_base, pos + i); > + > + return i; > +} > + > +static const struct of_device_id sunxi_sid_of_match[] = { > + { .compatible = "allwinner,sun4i-sid", }, > + {/* sentinel */} > +}; > +MODULE_DEVICE_TABLE(of, sunxi_sid_of_match); > + > +static const struct bin_attribute sid_bin_attr = { > + .attr = { > + .name = "eeprom", > + .mode = S_IRUGO, > + }, > + .size = SID_SIZE, > + .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, "%s driver unloaded\n", DRV_NAME); > + > + return 0; > +} > + > +static int __init sunxi_sid_probe(struct platform_device *pdev) > +{ > + u8 entropy[SID_SIZE]; > + unsigned int i; > + struct resource *res; > + void __iomem *sid_reg_base; > + int ret; > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + sid_reg_base = devm_ioremap_resource(&pdev->dev, res); > + if (IS_ERR(sid_reg_base)) > + return PTR_ERR(sid_reg_base); > + platform_set_drvdata(pdev, sid_reg_base); > + > + ret = device_create_bin_file(&pdev->dev, &sid_bin_attr); > + if (ret) > + return ret; > + > + for (i = 0; i < SID_SIZE; i++) > + entropy[i] = sunxi_sid_read_byte(sid_reg_base, i); > + add_device_randomness(entropy, SID_SIZE); > + dev_dbg(&pdev->dev, "%s loaded\n", DRV_NAME); > + > + 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 <[email protected]>"); > +MODULE_DESCRIPTION("Allwinner sunxi security id driver"); > +MODULE_LICENSE("GPL"); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
