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Subject[PATCH] edac.h: Add generic layers for describing a memory location
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The edac core were written with the idea that memory controllers
are able to directly access csrows, and that the channels are
used inside a csrows select.

This is not true for FB-DIMM and RAMBUS memory controllers.

Also, some recent advanced memory controllers don't present a per-csrows
view. Instead, they view memories as DIMMs, instead of ranks, accessed
via csrow/channel.

So, changes are needed in order to allow the EDAC core to
work with all types of architectures.

In preparation for handling non-csrows based memory controllers,
add some memory structs and a macro:

enum hw_event_mc_err_type: describes the type of error
(corrected, uncorrected, fatal)

To be used by the new edac_mc_handle_error function;

enum edac_mc_layer: describes the type of a given memory
architecture layer (branch, channel, slot, csrow).

struct edac_mc_layer: describes the properties of a memory
layer (type, size, and if the layer
will be used on a virtual csrow.

EDAC_DIMM_PTR() - as the number of layers can vary from 1 to 3,
this macro converts from an address with up to 3 layers into
a linear address.

Reviewed-by: Borislav Petkov <bp@amd64.org>
Cc: Doug Thompson <norsk5@yahoo.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
---
v15 - Added/improved comments and some vars/macros got renamed

include/linux/edac.h | 103 +++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 102 insertions(+), 1 deletions(-)
diff --git a/include/linux/edac.h b/include/linux/edac.h
index 8b78bd0..3b8798d 100644
--- a/include/linux/edac.h
+++ b/include/linux/edac.h
@@ -67,6 +67,25 @@ enum dev_type {
#define DEV_FLAG_X64 BIT(DEV_X64)

/**
+ * enum hw_event_mc_err_type - type of the detected error
+ *
+ * @HW_EVENT_ERR_CORRECTED: Corrected Error - Indicates that an ECC
+ * corrected error was detected
+ * @HW_EVENT_ERR_UNCORRECTED: Uncorrected Error - Indicates an error that
+ * can't be corrected by ECC, but it is not
+ * fatal (maybe it is on an unused memory area,
+ * or the memory controller could recover from
+ * it for example, by re-trying the operation).
+ * @HW_EVENT_ERR_FATAL: Fatal Error - Uncorrected error that could not
+ * be recovered.
+ */
+enum hw_event_mc_err_type {
+ HW_EVENT_ERR_CORRECTED,
+ HW_EVENT_ERR_UNCORRECTED,
+ HW_EVENT_ERR_FATAL,
+};
+
+/**
* enum mem_type - memory types. For a more detailed reference, please see
* http://en.wikipedia.org/wiki/DRAM
*
@@ -308,7 +327,89 @@ enum scrub_type {
* PS - I enjoyed writing all that about as much as you enjoyed reading it.
*/

-/* FIXME: add a per-dimm ce error count */
+/**
+ * enum edac_mc_layer - memory controller hierarchy layer
+ *
+ * @EDAC_MC_LAYER_BRANCH: memory layer is named "branch"
+ * @EDAC_MC_LAYER_CHANNEL: memory layer is named "channel"
+ * @EDAC_MC_LAYER_SLOT: memory layer is named "slot"
+ * @EDAC_MC_LAYER_CHIP_SELECT: memory layer is named "chip select"
+ *
+ * This enum is used by the drivers to tell edac_mc_sysfs what name should
+ * be used when describing a memory stick location.
+ */
+enum edac_mc_layer_type {
+ EDAC_MC_LAYER_BRANCH,
+ EDAC_MC_LAYER_CHANNEL,
+ EDAC_MC_LAYER_SLOT,
+ EDAC_MC_LAYER_CHIP_SELECT,
+};
+
+/**
+ * struct edac_mc_layer - describes the memory controller hierarchy
+ * @layer: layer type
+ * @size: number of components per layer. For example,
+ * if the channel layer has two channels, size = 2
+ * @is_virt_csrow: This layer is part of the "csrow" when old API
+ * compatibility mode is enabled. Otherwise, it is
+ * a channel
+ */
+struct edac_mc_layer {
+ enum edac_mc_layer_type type;
+ unsigned size;
+ bool is_virt_csrow;
+};
+
+/*
+ * Maximum number of layers used by the memory controller to uniquely
+ * identify a single memory stick.
+ * NOTE: Changing this constant requires not only to change the constant
+ * below, but also to change the existing code at the core, as there are
+ * some code there that are optimized for 3 layers.
+ */
+#define EDAC_MAX_LAYERS 3
+
+/**
+ * EDAC_DIMM_PTR - Macro responsible to find a pointer inside a pointer array
+ * for the element given by [layer0,layer1,layer2] position
+ *
+ * @layers: a struct edac_mc_layer array, describing how many elements
+ * were allocated for each layer
+ * @var: name of the var where we want to get the pointer
+ * (like mci->dimms)
+ * @n_layers: Number of layers at the @layers array
+ * @layer0: layer0 position
+ * @layer1: layer1 position. Unused if n_layers < 2
+ * @layer2: layer2 position. Unused if n_layers < 3
+ *
+ * For 1 layer, this macro returns &var[layer0]
+ * For 2 layers, this macro is similar to allocate a bi-dimensional array
+ * and to return "&var[layer0][layer1]"
+ * For 3 layers, this macro is similar to allocate a tri-dimensional array
+ * and to return "&var[layer0][layer1][layer2]"
+ *
+ * A loop could be used here to make it more generic, but, as we only have
+ * 3 layers, this is a little faster.
+ * By design, layers can never be 0 or more than 3. If that ever happens,
+ * a NULL is returned, causing an OOPS during the memory allocation routine,
+ * with would point to the developer that he's doing something wrong.
+ */
+#define EDAC_DIMM_PTR(layers, var, nlayers, layer0, layer1, layer2) ({ \
+ typeof(var) __p; \
+ if ((nlayers) == 1) \
+ __p = &var[layer0]; \
+ else if ((nlayers) == 2) \
+ __p = &var[(layer1) + ((layers[1]).size * (layer0))]; \
+ else if ((nlayers) == 3) \
+ __p = &var[(layer2) + ((layers[2]).size * ((layer1) + \
+ ((layers[1]).size * (layer0))))]; \
+ else \
+ __p = NULL; \
+ __p; \
+})
+
+
+/* FIXME: add the proper per-location error counts */
struct dimm_info {
char label[EDAC_MC_LABEL_LEN + 1]; /* DIMM label on motherboard */
unsigned memory_controller;
--
1.7.8


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