This is needed with the pl011 driver. Before this change it would default
to a shift of 0, however the hardware places the registers at 4-byte
addresses meaning the value should be 2.
This patch fixes this for the pl011 when configured using the fdt. The
other drivers have a default value of 0 to keep this a no-op.
MFC after: 1 week
uart implementations, and export them using the new linker-set mechanism.
Differential Revision: https://reviews.freebsd.org/D1993
Submitted by: Michal Meloun
is the case, depending on the options, in some of the ARM hardware
simulators. In these cases we don't get an interrupt so will need to
schedule the task to write more data to the uart.
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Instead of waiting for empty TX FIFO it is more reasonable to
block on full FIFO. As soon as FIFO slot is free the character
can be transmitted.
In case of TX FIFO disabled, TXFF bit indicates that transmit
register is not empty.
Obtained from: Semihalf
Reviewed by: andrew, emaste
Sponsored by: The FreeBSD Foundation
console, it calls the grab functions. These functions should turn off
the RX interrupts, and any others that interfere. This makes mountroot
prompt work again. If there's more generalized need other than
prompting, many of these routines should be expanded to do those new
things.
Should have been part of r260889, but waasn't due to command line typo.
Reviewed by: bde (with reservations)
uart(4) allocates send and receiver buffers in attach() before it calls
the low-level driver's attach routine. Many low-level drivers set the
fifo sizes in their attach routine, which is too late. Other drivers set
them in the probe() routine, so that they're available when uart(4)
allocates buffers. This fixes the ones that were setting the values too
late by moving the code to probe().
