This patch implements functionalities of following ioctls:
RTC_IRQP_READ, RTC_IRQP_SET - Getting/Setting IRQ rate
Read and set the frequency for periodic interrupts, for RTCs
that support periodic interrupts. The periodic interrupt must
be separately enabled or disabled using the RTC_PIE_ON,
RTC_PIE_OFF requests. The third ioctl's argument is an
unsigned long * or an unsigned long, respectively. The value
is the frequency in interrupts per second. The set of allow‐
able frequencies is the multiples of two in the range 2 to
8192. Only a privileged process (i.e., one having the
CAP_SYS_RESOURCE capability) can set frequencies above the
value specified in /proc/sys/dev/rtc/max-user-freq. (This
file contains the value 64 by default.)
RTC_EPOCH_READ, RTC_EPOCH_SET - Getting/Setting epoch
Many RTCs encode the year in an 8-bit register which is either
interpreted as an 8-bit binary number or as a BCD number. In
both cases, the number is interpreted relative to this RTC's
Epoch. The RTC's Epoch is initialized to 1900 on most systems
but on Alpha and MIPS it might also be initialized to 1952,
1980, or 2000, depending on the value of an RTC register for
the year. With some RTCs, these operations can be used to
read or to set the RTC's Epoch, respectively. The third
ioctl's argument is an unsigned long * or an unsigned long,
respectively, and the value returned (or assigned) is the
Epoch. To set the RTC's Epoch the process must be privileged
(i.e., have the CAP_SYS_TIME capability).
Implementation notes:
All ioctls in this patch have a pointer to 'ulong' as their
third argument. That is the reason why corresponding parts
of added code in linux-user/syscall_defs.h contain special
handling related to 'ulong' type: they use 'abi_ulong' type
to make sure that ioctl's code is calculated correctly for
both 32-bit and 64-bit targets. Also, 'MK_PTR(TYPE_ULONG)'
is used for the similar reason in linux-user/ioctls.h.
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Filip Bozuta <Filip.Bozuta@rt-rk.com>
Message-Id: <1579117007-7565-4-git-send-email-Filip.Bozuta@rt-rk.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
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