linux.git/drivers/mailbox/pcc.c, branch v4.9

mailbox: PCC: Fix lockdep warning when request PCC channel

2016-11-14T21:07:38+00:00

This patch fixes the lockdep warning below

DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
------------[ cut here ]------------
WARNING: CPU: 1 PID: 1 at linux-next/kernel/locking/lockdep.c:2876 lockdep_trace_alloc+0xe0/0xf0
 Modules linked in:

 CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.8.0-11756-g86c5152 #46
...
 Call trace:
 Exception stack(0xffff8007da837890 to 0xffff8007da8379c0)
 7880:                                   ffff8007da834000 0001000000000000
 78a0: ffff8007da837a70 ffff0000081111a0 00000000600000c5 000000000000003d
 78c0: 9374bc6a7f3c7832 0000000000381878 ffff000009db7ab8 000000000000002f
 78e0: ffff00000811aabc ffff000008be2548 ffff8007da837990 ffff00000811adf8
 7900: ffff8007da834000 00000000024080c0 00000000000000c0 ffff000009021000
 7920: 0000000000000000 0000000000000000 ffff000008c8f7c8 ffff8007da579810
 7940: 000000000000002f ffff8007da858000 0000000000000000 0000000000000001
 7960: 0000000000000001 0000000000000000 ffff00000811a468 0000000000000002
 7980: 656c62617369645f 0000000000038187 00000000000000ee ffff8007da837850
 79a0: ffff000009db50c0 ffff000009db569d 0000000000000006 ffff000089db568f
 [] lockdep_trace_alloc+0xe0/0xf0
 [] __kmalloc_track_caller+0x50/0x250
 [] devres_alloc_node+0x28/0x60
 [] devm_request_threaded_irq+0x50/0xe0
 [] pcc_mbox_request_channel+0x110/0x170
 [] acpi_cppc_processor_probe+0x264/0x414
 [] __acpi_processor_start+0x28/0xa0
 [] acpi_processor_start+0x44/0x54
 [] driver_probe_device+0x1fc/0x2b0
 [] __driver_attach+0xb4/0xc0
 [] bus_for_each_dev+0x5c/0xa0
 [] driver_attach+0x20/0x30
 [] bus_add_driver+0x110/0x230
 [] driver_register+0x60/0x100
 [] acpi_processor_driver_init+0x2c/0xb0
 [] do_one_initcall+0x38/0x130
 [] kernel_init_freeable+0x210/0x2b4
 [] kernel_init+0x10/0x110
 [] ret_from_fork+0x10/0x50

It's because the spinlock inside pcc_mbox_request_channel() is
kept too long. This patch releases spinlock before request_irq()
and free_irq() to fix this issue  as spinlock is only needed to
protect the channel data.

Signed-off-by: Hoan Tran 
Reviewed-by: Prashanth Prakash 
Signed-off-by: Rafael J. Wysocki

mailbox: pcc: Support HW-Reduced Communication Subspace type 2

2016-08-30T22:37:20+00:00

ACPI 6.1 has a PCC HW-Reduced Communication Subspace type 2 intended for
use on HW-Reduce ACPI Platform, which requires read-modify-write sequence
to acknowledge doorbell interrupt. This patch provides the implementation
for the Communication Subspace Type 2.

Signed-off-by: Hoan Tran 
Reviewed-by: Prashanth Prakash 
Signed-off-by: Rafael J. Wysocki

Merge branches 'pm-cpufreq', 'pm-cpuidle' and 'acpi-cppc'

2016-04-08T19:46:05+00:00

* pm-cpufreq:
  cpufreq: dt: Drop stale comment
  cpufreq: intel_pstate: Documenation for structures
  cpufreq: intel_pstate: fix inconsistency in setting policy limits
  intel_pstate: Avoid extra invocation of intel_pstate_sample()
  intel_pstate: Do not set utilization update hook too early

* pm-cpuidle:
  intel_idle: Add KBL support
  intel_idle: Add SKX support
  intel_idle: Clean up all registered devices on exit.
  intel_idle: Propagate hot plug errors.
  intel_idle: Don't overreact to a cpuidle registration failure.
  intel_idle: Setup the timer broadcast only on successful driver load.
  intel_idle: Avoid a double free of the per-CPU data.
  intel_idle: Fix dangling registration on error path.
  intel_idle: Fix deallocation order on the driver exit path.
  intel_idle: Remove redundant initialization calls.
  intel_idle: Fix a helper function's return value.
  intel_idle: remove useless return from void function.

* acpi-cppc:
  mailbox: pcc: Don't access an unmapped memory address space

mailbox: pcc: Don't access an unmapped memory address space

2016-04-06T23:25:28+00:00

The acpi_pcc_probe() may end up accessing memory outside of the PCCT
table space causing the kernel panic(). Increment the pcct_entry
pointer after parsing 'HW-reduced Communications Subspace' to fix
the problem. This change also enables the parsing of subtable at
index 0.

Signed-off-by: Shanker Donthineni 
Acked-by: Ashwin Chaugule 
Signed-off-by: Rafael J. Wysocki

Merge branches 'acpi-processor' and 'acpi-cppc'

2016-03-14T13:20:33+00:00

* acpi-processor:
  ACPI / sleep: move acpi_processor_sleep to sleep.c
  ACPI / processor : add support for ACPI0010 processor container
  ACPI / processor_idle: replace PREFIX with pr_fmt

* acpi-cppc:
  ACPI / CPPC: use MRTT/MPAR to decide if/when a req can be sent
  ACPI / CPPC: replace writeX/readX to PCC with relaxed version
  mailbox: pcc: optimized pcc_send_data
  ACPI / CPPC: optimized cpc_read and cpc_write
  ACPI / CPPC: Optimize PCC Read Write operations

mailbox: pcc: optimized pcc_send_data

2016-03-09T22:35:29+00:00

pcc_send_data() can be invoked during the execution of performance
critical code as in cppc_cpufreq driver. With acpi_* APIs, the
doorbell register accessed in pcc_send_data() if present in system
memory will be searched (in cached virt to phys addr mapping),
mapped, read/written and then unmapped. These operations take
significant amount of time.

This patch maps the performance critical doorbell register
during init and then reads/writes to it directly using the
mapped virtual address. This patch + similar changes to CPPC
acpi driver reduce the time per freq. transition from around
200us to about 20us for the CPPC cpufreq driver

Signed-off-by: Prashanth Prakash 
Acked-by: Ashwin Chaugule 
Signed-off-by: Rafael J. Wysocki

mailbox: pcc: fix channel calculation in get_pcc_channel()

2016-02-02T11:09:13+00:00

This patch fixes the calculation of pcc_chan for non-zero id.
After the compiler ignores the (unsigned long) cast the
pcc_mbox_channels pointer is type-cast and then the type-cast
offset is added which results in address outside of the range
leading to the kernel crashing.

We might add braces and make it:

pcc_chan = (struct mbox_chan *)
		((unsigned long) pcc_mbox_channels +
		(id * sizeof(*pcc_chan)));

but let's go with array approach here and use id as index.

Tested on Juno board.

Signed-off-by: Alexey Klimov 
Acked-by: Sudeep Holla 
Acked-by: Ashwin Chaugule 
Signed-off-by: Jassi Brar

PCC: fix dereference of ERR_PTR

2015-10-16T05:16:07+00:00

get_pcc_channel() does not return NULL on error it returns the error code
in ERR_PTR, but we have been checking it for NULL.

Signed-off-by: Sudip Mukherjee

PCC: Initialize PCC Mailbox earlier at boot

2015-08-25T01:25:46+00:00

This change initializes the PCC Mailbox earlier than
the ACPI processor driver. This enables drivers introduced
in follow up patches (e.g. CPPC) to be probed via the ACPI
processor driver interface. The CPPC probe requires the PCC
channel to be initialized for it to query each CPUs performance
capabilities.

Signed-off-by: Ashwin Chaugule 
Reviewed-by: Al Stone 
Signed-off-by: Rafael J. Wysocki

mailbox: Make mbox_chan_ops const

2015-05-12T03:48:16+00:00

The mailbox controller's channel ops ought to be read-only.  Update
all the mailbox drivers to make their mbox_chan_ops const as well.

Signed-off-by: Andrew Bresticker 
Cc: Ashwin Chaugule 
Cc: Ley Foon Tan 
Acked-by: Suman Anna 
Signed-off-by: Jassi Brar