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authorLinus Torvalds <torvalds@linux-foundation.org>2014-08-08 14:34:32 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2014-08-08 14:34:32 -0400
commit10c8e0562057b5d64ea170feab148e1550420030 (patch)
treecfd387208c85e893c93d24e324d147eb6e9abfc9 /Documentation/arm
parentd4e1f5a14e17d4f0e8034c0967511884bcb12fba (diff)
parent3e528cb7bae00ba0d73def6645d0f2fa906ee3e8 (diff)
Merge tag 'drivers-for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC driver changes from Olof Johansson: "A handful of driver-related changes. We've had a bunch of them going in through other branches as well, so it's only a part of what we really have this release. Larger pieces are: - Removal of a now unused PWM driver for atmel [ This includes AVR32 changes that have been appropriately acked ] - Performance counter support for the arm CCN interconnect - OMAP mailbox driver cleanups and consolidation - PCI and SATA PHY drivers for SPEAr 13xx platforms - Redefinition (with backwards compatibility!) of PCI DT bindings for Tegra to better model regulators/power" Note: this merge also fixes up the semantic conflict with the new calling convention for devm_phy_create(), see commit f0ed817638b5 ("phy: core: Let node ptr of PHY point to PHY and not of PHY provider") that came in through Greg's USB tree. Semantic merge patch by Stephen Rothwell <sfr@canb.auug.org.au> through the next tree. * tag 'drivers-for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (38 commits) bus: arm-ccn: Fix error handling at event allocation mailbox/omap: add a parent structure for every IP instance mailbox/omap: remove the private mailbox structure mailbox/omap: consolidate OMAP mailbox driver mailbox/omap: simplify the fifo assignment by using macros mailbox/omap: remove omap_mbox_type_t from mailbox ops mailbox/omap: remove OMAP1 mailbox driver mailbox/omap: use devm_* interfaces bus: ARM CCN: add PERF_EVENTS dependency bus: ARM CCN PMU driver PCI: spear: Remove spear13xx_pcie_remove() PCI: spear: Fix Section mismatch compilation warning for probe() ARM: tegra: Remove legacy PCIe power supply properties PCI: tegra: Remove deprecated power supply properties PCI: tegra: Implement accurate power supply scheme ARM: SPEAr13xx: Update defconfigs ARM: SPEAr13xx: Add pcie and miphy DT nodes ARM: SPEAr13xx: Add bindings and dt node for misc block ARM: SPEAr13xx: Fix static mapping table phy: Add drivers for PCIe and SATA phy on SPEAr13xx ...
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1ARM Cache Coherent Network
2==========================
3
4CCN-504 is a ring-bus interconnect consisting of 11 crosspoints
5(XPs), with each crosspoint supporting up to two device ports,
6so nodes (devices) 0 and 1 are connected to crosspoint 0,
7nodes 2 and 3 to crosspoint 1 etc.
8
9PMU (perf) driver
10-----------------
11
12The CCN driver registers a perf PMU driver, which provides
13description of available events and configuration options
14in sysfs, see /sys/bus/event_source/devices/ccn*.
15
16The "format" directory describes format of the config, config1
17and config2 fields of the perf_event_attr structure. The "events"
18directory provides configuration templates for all documented
19events, that can be used with perf tool. For example "xp_valid_flit"
20is an equivalent of "type=0x8,event=0x4". Other parameters must be
21explicitly specified. For events originating from device, "node"
22defines its index. All crosspoint events require "xp" (index),
23"port" (device port number) and "vc" (virtual channel ID) and
24"dir" (direction). Watchpoints (special "event" value 0xfe) also
25require comparator values ("cmp_l" and "cmp_h") and "mask", being
26index of the comparator mask.
27
28Masks are defined separately from the event description
29(due to limited number of the config values) in the "cmp_mask"
30directory, with first 8 configurable by user and additional
314 hardcoded for the most frequent use cases.
32
33Cycle counter is described by a "type" value 0xff and does
34not require any other settings.
35
36Example of perf tool use:
37
38/ # perf list | grep ccn
39 ccn/cycles/ [Kernel PMU event]
40<...>
41 ccn/xp_valid_flit/ [Kernel PMU event]
42<...>
43
44/ # perf stat -C 0 -e ccn/cycles/,ccn/xp_valid_flit,xp=1,port=0,vc=1,dir=1/ \
45 sleep 1
46
47The driver does not support sampling, therefore "perf record" will
48not work. Also notice that only single cpu is being selected
49("-C 0") - this is because perf framework does not support
50"non-CPU related" counters (yet?) so system-wide session ("-a")
51would try (and in most cases fail) to set up the same event
52per each CPU.