From 6634fbb6b6356e6f5b428a349952b368b25d514d Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Wed, 26 Oct 2016 14:14:45 -0200 Subject: [PATCH] driver-api: create an edac.rst file with EDAC documentation Currently, there's no device driver documentation for the EDAC subsystem at the driver-api book. Fill in the blanks for the structures and functions that misses documentation, uniform the word on the existing ones, and add a new edac.rst file at driver-api, in order to document the EDAC subsystem. Signed-off-by: Mauro Carvalho Chehab --- Documentation/driver-api/edac.rst | 72 ++++++++++++++++++++++++++++++ Documentation/driver-api/index.rst | 1 + drivers/edac/edac_mc.h | 2 - 3 files changed, 73 insertions(+), 2 deletions(-) create mode 100644 Documentation/driver-api/edac.rst diff --git a/Documentation/driver-api/edac.rst b/Documentation/driver-api/edac.rst new file mode 100644 index 000000000000..3771e768fda1 --- /dev/null +++ b/Documentation/driver-api/edac.rst @@ -0,0 +1,72 @@ +Error Detection And Correction (EDAC) Devices +============================================= + +Memory Controllers +------------------ + +Most of the EDAC core is focused on doing Memory Controller error detection. +The :c:func:`edac_mc_alloc`. It uses internally the struct ``mem_ctl_info`` +to describe the memory controllers, with is an opaque struct for the EDAC +drivers. Only the EDAC core is allowed to touch it. + +.. kernel-doc:: include/linux/edac.h + +.. kernel-doc:: drivers/edac/edac_mc.h + +PCI Controllers +--------------- + +The EDAC subsystem provides a mechanism to handle PCI controllers by calling +the :c:func:`edac_pci_alloc_ctl_info`. It will use the struct +:c:type:`edac_pci_ctl_info` to describe the PCI controllers. + +.. kernel-doc:: drivers/edac/edac_pci.h + +EDAC Blocks +----------- + +The EDAC subsystem also provides a generic mechanism to report errors on +other parts of the hardware via :c:func:`edac_device_alloc_ctl_info` function. + +The structures :c:type:`edac_dev_sysfs_block_attribute`, +:c:type:`edac_device_block`, :c:type:`edac_device_instance` and +:c:type:`edac_device_ctl_info` provide a generic or abstract 'edac_device' +representation at sysfs. + +This set of structures and the code that implements the APIs for the same, provide for registering EDAC type devices which are NOT standard memory or +PCI, like: + +- CPU caches (L1 and L2) +- DMA engines +- Core CPU switches +- Fabric switch units +- PCIe interface controllers +- other EDAC/ECC type devices that can be monitored for + errors, etc. + +It allows for a 2 level set of hierarchy. + +For example, a cache could be composed of L1, L2 and L3 levels of cache. +Each CPU core would have its own L1 cache, while sharing L2 and maybe L3 +caches. On such case, those can be represented via the following sysfs +nodes:: + + /sys/devices/system/edac/.. + + pci/ + mc/ + cpu/cpu0/.. + /L1-cache/ce_count + /ue_count + /L2-cache/ce_count + /ue_count + cpu/cpu1/.. + /L1-cache/ce_count + /ue_count + /L2-cache/ce_count + /ue_count + ... + + the L1 and L2 directories would be "edac_device_block's" + +.. kernel-doc:: drivers/edac/edac_device.h diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst index a528178a54a5..5475a2807e7a 100644 --- a/Documentation/driver-api/index.rst +++ b/Documentation/driver-api/index.rst @@ -26,6 +26,7 @@ available subsections can be seen below. spi i2c hsi + edac miscellaneous vme 80211/index diff --git a/drivers/edac/edac_mc.h b/drivers/edac/edac_mc.h index 97ee6a91f633..dcc2c7e3b8bc 100644 --- a/drivers/edac/edac_mc.h +++ b/drivers/edac/edac_mc.h @@ -152,8 +152,6 @@ extern void edac_mc_free(struct mem_ctl_info *mci); * * If found, return a pointer to the structure. * Else return NULL. - * - * Caller must hold mem_ctls_mutex. */ extern struct mem_ctl_info *edac_mc_find(int idx); -- 2.20.1