Revision 706a1ea65e6faaf853427a0e931f59d604dd45e3 authored by Linus Torvalds on 23 August 2018, 21:55:01 UTC, committed by Linus Torvalds on 23 August 2018, 21:55:01 UTC
Merge fixes for missing TLB shootdowns. This fixes a couple of cases that involved us possibly freeing page table structures before the required TLB shootdown had been done. There are a few cleanup patches to make the code easier to follow, and to avoid some of the more problematic cases entirely when not necessary. To make this easier for backports, it undoes the recent lazy TLB patches, because the cleanups and fixes are more important, and Rik is ok with re-doing them later when things have calmed down. The missing TLB flush was only delayed, and the wrong ordering only happened under memory pressure (and in theory under a couple of other fairly theoretical situations), so this may have been all very unlikely to have hit people in practice. But getting the TLB shootdown wrong is _so_ hard to debug and see that I consider this a crticial fix. Many thanks to Jann Horn for having debugged this. * tlb-fixes: x86/mm: Only use tlb_remove_table() for paravirt mm: mmu_notifier fix for tlb_end_vma mm/tlb, x86/mm: Support invalidating TLB caches for RCU_TABLE_FREE mm/tlb: Remove tlb_remove_table() non-concurrent condition mm: move tlb_table_flush to tlb_flush_mmu_free x86/mm/tlb: Revert the recent lazy TLB patches
smsc_ece1099.txt
=================================================
Msc Keyboard Scan Expansion/GPIO Expansion device
=================================================
What is smsc-ece1099?
----------------------
The ECE1099 is a 40-Pin 3.3V Keyboard Scan Expansion
or GPIO Expansion device. The device supports a keyboard
scan matrix of 23x8. The device is connected to a Master
via the SMSC BC-Link interface or via the SMBus.
Keypad scan Input(KSI) and Keypad Scan Output(KSO) signals
are multiplexed with GPIOs.
Interrupt generation
--------------------
Interrupts can be generated by an edge detection on a GPIO
pin or an edge detection on one of the bus interface pins.
Interrupts can also be detected on the keyboard scan interface.
The bus interrupt pin (BC_INT# or SMBUS_INT#) is asserted if
any bit in one of the Interrupt Status registers is 1 and
the corresponding Interrupt Mask bit is also 1.
In order for software to determine which device is the source
of an interrupt, it should first read the Group Interrupt Status Register
to determine which Status register group is a source for the interrupt.
Software should read both the Status register and the associated Mask register,
then AND the two values together. Bits that are 1 in the result of the AND
are active interrupts. Software clears an interrupt by writing a 1 to the
corresponding bit in the Status register.
Communication Protocol
----------------------
- SMbus slave Interface
The host processor communicates with the ECE1099 device
through a series of read/write registers via the SMBus
interface. SMBus is a serial communication protocol between
a computer host and its peripheral devices. The SMBus data
rate is 10KHz minimum to 400 KHz maximum
- Slave Bus Interface
The ECE1099 device SMBus implementation is a subset of the
SMBus interface to the host. The device is a slave-only SMBus device.
The implementation in the device is a subset of SMBus since it
only supports four protocols.
The Write Byte, Read Byte, Send Byte, and Receive Byte protocols are the
only valid SMBus protocols for the device.
- BC-LinkTM Interface
The BC-Link is a proprietary bus that allows communication
between a Master device and a Companion device. The Master
device uses this serial bus to read and write registers
located on the Companion device. The bus comprises three signals,
BC_CLK, BC_DAT and BC_INT#. The Master device always provides the
clock, BC_CLK, and the Companion device is the source for an
independent asynchronous interrupt signal, BC_INT#. The ECE1099
supports BC-Link speeds up to 24MHz.
Computing file changes ...
