GRU Driver V3: fixes to resolve code review comments

Fixes problems identified in a code review:
	- add comment with high level dscription of the GRU
	- prepend "gru_" to all global names
	- delete unused function
	- couple of trivial bug fixes

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Jack Steiner <steiner@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 69 insertions, 5 deletions

diff --git a/drivers/misc/sgi-gru/grutables.h b/drivers/misc/sgi-gru/grutables.h
index f97d84640129..4251018f70ff 100644
--- a/drivers/misc/sgi-gru/grutables.h
+++ b/drivers/misc/sgi-gru/grutables.h
@@ -24,6 +24,70 @@
 #define __GRUTABLES_H__
 
 /*
+ * GRU Chiplet:
+ *   The GRU is a user addressible memory accelerator. It provides
+ *   several forms of load, store, memset, bcopy instructions. In addition, it
+ *   contains special instructions for AMOs, sending messages to message
+ *   queues, etc.
+ *
+ *   The GRU is an integral part of the node controller. It connects
+ *   directly to the cpu socket. In its current implementation, there are 2
+ *   GRU chiplets in the node controller on each blade (~node).
+ *
+ *   The entire GRU memory space is fully coherent and cacheable by the cpus.
+ *
+ *   Each GRU chiplet has a physical memory map that looks like the following:
+ *
+ *      +-----------------+
+ *      |/////////////////|
+ *      |/////////////////|
+ *      |/////////////////|
+ *      |/////////////////|
+ *      |/////////////////|
+ *      |/////////////////|
+ *      |/////////////////|
+ *      |/////////////////|
+ *      +-----------------+
+ *      |  system control |
+ *      +-----------------+        _______ +-------------+
+ *      |/////////////////|       /        |             |
+ *      |/////////////////|      /         |             |
+ *      |/////////////////|     /          | instructions|
+ *      |/////////////////|    /           |             |
+ *      |/////////////////|   /            |             |
+ *      |/////////////////|  /             |-------------|
+ *      |/////////////////| /              |             |
+ *      +-----------------+                |             |
+ *      |   context 15    |                |  data       |
+ *      +-----------------+                |             |
+ *      |    ......       | \              |             |
+ *      +-----------------+  \____________ +-------------+
+ *      |   context 1     |
+ *      +-----------------+
+ *      |   context 0     |
+ *      +-----------------+
+ *
+ *   Each of the "contexts" is a chunk of memory that can be mmaped into user
+ *   space. The context consists of 2 parts:
+ *
+ *      - an instruction space that can be directly accessed by the user
+ *        to issue GRU instructions and to check instruction status.
+ *
+ *      - a data area that acts as normal RAM.
+ *
+ *   User instructions contain virtual addresses of data to be accessed by the
+ *   GRU. The GRU contains a TLB that is used to convert these user virtual
+ *   addresses to physical addresses.
+ *
+ *   The "system control" area of the GRU chiplet is used by the kernel driver
+ *   to manage user contexts and to perform functions such as TLB dropin and
+ *   purging.
+ *
+ *   One context may be reserved for the kernel and used for cross-partition
+ *   communication. The GRU will also be used to asynchronously zero out
+ *   large blocks of memory (not currently implemented).
+ *
+ *
  * Tables:
  *
  *      VDATA-VMA Data          - Holds a few parameters. Head of linked list of
@@ -190,14 +254,14 @@ struct gru_stats_s {
 #define GRU_STEAL_DELAY         ((HZ * 200) / 1000)
 
 #define STAT(id)        do {                                            \
-                                if (options & OPT_STATS)                \
+                                if (gru_options & OPT_STATS)            \
                                         atomic_long_inc(&gru_stats.id); \
                         } while (0)
 
 #ifdef CONFIG_SGI_GRU_DEBUG
 #define gru_dbg(dev, fmt, x...)                                         \
         do {                                                            \
-                if (options & OPT_DPRINT)                               \
+                if (gru_options & OPT_DPRINT)                           \
                         dev_dbg(dev, "%s: " fmt, __func__, x);          \
         } while (0)
 #else
@@ -529,9 +593,9 @@ extern void gru_flush_all_tlb(struct gru_state *gru);
 extern int gru_proc_init(void);
 extern void gru_proc_exit(void);
 
-extern unsigned long reserve_gru_cb_resources(struct gru_state *gru,
+extern unsigned long gru_reserve_cb_resources(struct gru_state *gru,
                 int cbr_au_count, char *cbmap);
-extern unsigned long reserve_gru_ds_resources(struct gru_state *gru,
+extern unsigned long gru_reserve_ds_resources(struct gru_state *gru,
                 int dsr_au_count, char *dsmap);
 extern int gru_fault(struct vm_area_struct *, struct vm_fault *vmf);
 extern struct gru_mm_struct *gru_register_mmu_notifier(void);
@@ -540,6 +604,6 @@ extern void gru_drop_mmu_notifier(struct gru_mm_struct *gms);
 extern void gru_flush_tlb_range(struct gru_mm_struct *gms, unsigned long start,
                                         unsigned long len);
 
-extern unsigned long options;
+extern unsigned long gru_options;
 
 #endif /* __GRUTABLES_H__ */