diff options
| -rw-r--r-- | arch/arm/mach-tegra/Kconfig | 9 | ||||
| -rw-r--r-- | arch/arm/mach-tegra/Makefile | 1 | ||||
| -rw-r--r-- | arch/arm/mach-tegra/tegra_reg_access.c | 110 |
3 files changed, 120 insertions, 0 deletions
diff --git a/arch/arm/mach-tegra/Kconfig b/arch/arm/mach-tegra/Kconfig index 2f2888b5fa11..b5f0e336df76 100644 --- a/arch/arm/mach-tegra/Kconfig +++ b/arch/arm/mach-tegra/Kconfig @@ -242,3 +242,12 @@ config TEGRA_EDP_LIMITS Limit maximum CPU frequency based on temperature and number of on-line CPUs to keep CPU rail current within power supply capabilities. + +config TEGRA_REG_ACCESS + bool "Enable accessing Tegra Registers from user space" + default n + help + When enabled, the /dev/tegra_reg_access node is created, + which allows accessing Tegra Registers from user space. + This is for test purpose only. This should not be enabled + in production builds. diff --git a/arch/arm/mach-tegra/Makefile b/arch/arm/mach-tegra/Makefile index 704a4a4987b1..d809563ea53d 100644 --- a/arch/arm/mach-tegra/Makefile +++ b/arch/arm/mach-tegra/Makefile @@ -75,6 +75,7 @@ obj-$(CONFIG_TEGRA_IOVMM) += iovmm.o obj-$(CONFIG_TEGRA_IOVMM_GART) += iovmm-gart.o obj-$(CONFIG_TEGRA_IOVMM_SMMU) += iovmm-smmu.o obj-$(CONFIG_DEBUG_ICEDCC) += sysfs-dcc.o +obj-$(CONFIG_TEGRA_REG_ACCESS) += tegra_reg_access.o obj-$(CONFIG_TOUCHSCREEN_ATMEL_MT_T9) += board-touch-atmel_maxtouch.o obj-$(CONFIG_TOUCHSCREEN_PANJIT_I2C) += board-touch-panjit_i2c.o diff --git a/arch/arm/mach-tegra/tegra_reg_access.c b/arch/arm/mach-tegra/tegra_reg_access.c new file mode 100644 index 000000000000..dd110a8fc5b0 --- /dev/null +++ b/arch/arm/mach-tegra/tegra_reg_access.c @@ -0,0 +1,110 @@ +/* + * arch/arm/mach-tegra/tegra_reg_access.c + * + * Copyright (C) 2011 NVIDIA Corporation + * + * 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. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + */ + +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/miscdevice.h> +#include <linux/fs.h> +#include <asm/io.h> +#include <mach/iomap.h> + +static struct miscdevice dev; + +static int tegra_reg_access_open(struct inode *inode, struct file *filp) +{ + int ret; + + ret = nonseekable_open(inode, filp); + if (unlikely(ret)) + return ret; + return 0; +} + +static int tegra_reg_access_release(struct inode *inode, struct file *filp) +{ + return 0; +} + +#define TEGRA_REG_WRITE 0 +#define TEGRA_REG_READ 1 + +static long tegra_reg_access_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) +{ + /* + * For Reg Read, + * arg[0] = phys address, arg[1] = returns value read. + * For Reg Write, + * arg[0] = phys address, arg[1] = value to write. + */ + unsigned long *uarg = (unsigned long *)arg; + void __iomem *reg_addr = IO_ADDRESS(uarg[0]); + + if (reg_addr == NULL) + return -EINVAL; + + switch (cmd) { + case TEGRA_REG_READ: + uarg[1] = readl(reg_addr); + break; + case TEGRA_REG_WRITE: + writel(uarg[1], reg_addr); + break; + default: + pr_err("\n tegra_reg_access unknown ioctl cmd=%d\n", cmd); + return -EINVAL; + } + return 0; +} + +static const struct file_operations tegra_reg_access_fops = { + .owner = THIS_MODULE, + .open = tegra_reg_access_open, + .release = tegra_reg_access_release, + .unlocked_ioctl = tegra_reg_access_ioctl, +}; + +static int __devinit tegra_reg_access_init(void) +{ + int e; + + dev.minor = MISC_DYNAMIC_MINOR; + dev.name = "tegra_reg_access"; + dev.fops = &tegra_reg_access_fops; + dev.parent = NULL; + + e = misc_register(&dev); + if (e) { + pr_err("\nunable to register tegra_reg_access dev\n"); + return -ENODEV; + } + pr_warn("## WARNING: Tegra registers access, from user space, is enabled.\n" + "## This creates a hole in the system security.\n" + "## Ensure that this is intentional.\n"); + return 0; +} + +static void __exit tegra_reg_access_exit(void) +{ + misc_deregister(&dev); +} + +module_init(tegra_reg_access_init); +module_exit(tegra_reg_access_exit); |