diff options
Diffstat (limited to 'sys/isa/atrtc.c')
-rw-r--r-- | sys/isa/atrtc.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/sys/isa/atrtc.c b/sys/isa/atrtc.c index 62c5764..f8e1c4e 100644 --- a/sys/isa/atrtc.c +++ b/sys/isa/atrtc.c @@ -56,12 +56,15 @@ __FBSDID("$FreeBSD$"); #include <sys/systm.h> #include <sys/bus.h> #include <sys/clock.h> +#include <sys/conf.h> +#include <sys/fcntl.h> #include <sys/lock.h> #include <sys/kdb.h> #include <sys/mutex.h> #include <sys/proc.h> #include <sys/time.h> #include <sys/timetc.h> +#include <sys/uio.h> #include <sys/kernel.h> #include <sys/limits.h> #include <sys/module.h> @@ -930,4 +933,100 @@ static devclass_t attimer_devclass; DRIVER_MODULE(attimer, isa, attimer_driver, attimer_devclass, 0, 0); DRIVER_MODULE(attimer, acpi, attimer_driver, attimer_devclass, 0, 0); + +/* + * Linux-style /dev/nvram driver + * + * cmos ram starts at bytes 14 through 128, for a total of 114 bytes. + * bytes 16 through 31 are checksummed at byte 32. + * Unlike Linux, you have to take care of the checksums yourself. + * The driver exposes byte 14 as file offset 0. + */ + +#define NVRAM_FIRST RTC_DIAG /* 14 */ +#define NVRAM_LAST 128 + +static d_open_t nvram_open; +static d_read_t nvram_read; +static d_write_t nvram_write; + +static struct cdev *nvram_dev; + +static struct cdevsw nvram_cdevsw = { + .d_version = D_VERSION, + .d_flags = D_NEEDGIANT, + .d_open = nvram_open, + .d_read = nvram_read, + .d_write = nvram_write, + .d_name = "nvram", +}; + +static int +nvram_open(struct cdev *dev __unused, int flags, int fmt __unused, + struct thread *td) +{ + int error = 0; + + if (flags & FWRITE) + error = securelevel_gt(td->td_ucred, 0); + + return (error); +} + +static int +nvram_read(struct cdev *dev, struct uio *uio, int flags) +{ + int nv_off; + u_char v; + int error = 0; + + while (uio->uio_resid > 0 && error == 0) { + nv_off = uio->uio_offset + NVRAM_FIRST; + if (nv_off < NVRAM_FIRST || nv_off >= NVRAM_LAST) + return (0); /* Signal EOF */ + /* Single byte at a time */ + v = rtcin(nv_off); + error = uiomove(&v, 1, uio); + } + return (error); + +} + +static int +nvram_write(struct cdev *dev, struct uio *uio, int flags) +{ + int nv_off; + u_char v; + int error = 0; + + while (uio->uio_resid > 0 && error == 0) { + nv_off = uio->uio_offset + NVRAM_FIRST; + if (nv_off < NVRAM_FIRST || nv_off >= NVRAM_LAST) + return (0); /* Signal EOF */ + /* Single byte at a time */ + error = uiomove(&v, 1, uio); + writertc(nv_off, v); + } + return (error); +} + +static int +nvram_modevent(module_t mod __unused, int type, void *data __unused) +{ + switch (type) { + case MOD_LOAD: + nvram_dev = make_dev(&nvram_cdevsw, 0, + UID_ROOT, GID_KMEM, 0640, "nvram"); + break; + case MOD_UNLOAD: + case MOD_SHUTDOWN: + destroy_dev(nvram_dev); + break; + default: + return (EOPNOTSUPP); + } + return (0); +} +DEV_MODULE(nvram, nvram_modevent, NULL); + #endif /* DEV_ISA */ |