summaryrefslogtreecommitdiffstats
path: root/arch/arm/include/asm/cacheflush.h
diff options
context:
space:
mode:
authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2013-05-15 10:26:50 -0400
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2013-05-15 10:26:50 -0400
commit12e04ffcd93b25dfd726d46338c2ee7d23de556e (patch)
treef91479a62805619168994fd3ee55e3ffa23fc24e /arch/arm/include/asm/cacheflush.h
parent9eff37a8713939f218ab8bf0dc93f1d67af7b8b4 (diff)
parentf722406faae2d073cc1d01063d1123c35425939e (diff)
Merge tag 'v3.10-rc1' into stable/for-linus-3.10
Linux 3.10-rc1 * tag 'v3.10-rc1': (12273 commits) Linux 3.10-rc1 [SCSI] qla2xxx: Update firmware link in Kconfig file. [SCSI] iscsi class, qla4xxx: fix sess/conn refcounting when find fns are used [SCSI] sas: unify the pointlessly separated enums sas_dev_type and sas_device_type [SCSI] pm80xx: thermal, sas controller config and error handling update [SCSI] pm80xx: NCQ error handling changes [SCSI] pm80xx: WWN Modification for PM8081/88/89 controllers [SCSI] pm80xx: Changed module name and debug messages update [SCSI] pm80xx: Firmware flash memory free fix, with addition of new memory region for it [SCSI] pm80xx: SPC new firmware changes for device id 0x8081 alone [SCSI] pm80xx: Added SPCv/ve specific hardware functionalities and relevant changes in common files [SCSI] pm80xx: MSI-X implementation for using 64 interrupts [SCSI] pm80xx: Updated common functions common for SPC and SPCv/ve [SCSI] pm80xx: Multiple inbound/outbound queue configuration [SCSI] pm80xx: Added SPCv/ve specific ids, variables and modify for SPC [SCSI] lpfc: fix up Kconfig dependencies [SCSI] Handle MLQUEUE busy response in scsi_send_eh_cmnd dm cache: set config value dm cache: move config fns dm thin: generate event when metadata threshold passed ...
Diffstat (limited to 'arch/arm/include/asm/cacheflush.h')
-rw-r--r--arch/arm/include/asm/cacheflush.h75
1 files changed, 75 insertions, 0 deletions
diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h
index e1489c54cd1..bff71388e72 100644
--- a/arch/arm/include/asm/cacheflush.h
+++ b/arch/arm/include/asm/cacheflush.h
@@ -363,4 +363,79 @@ static inline void flush_cache_vunmap(unsigned long start, unsigned long end)
flush_cache_all();
}
+/*
+ * Memory synchronization helpers for mixed cached vs non cached accesses.
+ *
+ * Some synchronization algorithms have to set states in memory with the
+ * cache enabled or disabled depending on the code path. It is crucial
+ * to always ensure proper cache maintenance to update main memory right
+ * away in that case.
+ *
+ * Any cached write must be followed by a cache clean operation.
+ * Any cached read must be preceded by a cache invalidate operation.
+ * Yet, in the read case, a cache flush i.e. atomic clean+invalidate
+ * operation is needed to avoid discarding possible concurrent writes to the
+ * accessed memory.
+ *
+ * Also, in order to prevent a cached writer from interfering with an
+ * adjacent non-cached writer, each state variable must be located to
+ * a separate cache line.
+ */
+
+/*
+ * This needs to be >= the max cache writeback size of all
+ * supported platforms included in the current kernel configuration.
+ * This is used to align state variables to their own cache lines.
+ */
+#define __CACHE_WRITEBACK_ORDER 6 /* guessed from existing platforms */
+#define __CACHE_WRITEBACK_GRANULE (1 << __CACHE_WRITEBACK_ORDER)
+
+/*
+ * There is no __cpuc_clean_dcache_area but we use it anyway for
+ * code intent clarity, and alias it to __cpuc_flush_dcache_area.
+ */
+#define __cpuc_clean_dcache_area __cpuc_flush_dcache_area
+
+/*
+ * Ensure preceding writes to *p by this CPU are visible to
+ * subsequent reads by other CPUs:
+ */
+static inline void __sync_cache_range_w(volatile void *p, size_t size)
+{
+ char *_p = (char *)p;
+
+ __cpuc_clean_dcache_area(_p, size);
+ outer_clean_range(__pa(_p), __pa(_p + size));
+}
+
+/*
+ * Ensure preceding writes to *p by other CPUs are visible to
+ * subsequent reads by this CPU. We must be careful not to
+ * discard data simultaneously written by another CPU, hence the
+ * usage of flush rather than invalidate operations.
+ */
+static inline void __sync_cache_range_r(volatile void *p, size_t size)
+{
+ char *_p = (char *)p;
+
+#ifdef CONFIG_OUTER_CACHE
+ if (outer_cache.flush_range) {
+ /*
+ * Ensure dirty data migrated from other CPUs into our cache
+ * are cleaned out safely before the outer cache is cleaned:
+ */
+ __cpuc_clean_dcache_area(_p, size);
+
+ /* Clean and invalidate stale data for *p from outer ... */
+ outer_flush_range(__pa(_p), __pa(_p + size));
+ }
+#endif
+
+ /* ... and inner cache: */
+ __cpuc_flush_dcache_area(_p, size);
+}
+
+#define sync_cache_w(ptr) __sync_cache_range_w(ptr, sizeof *(ptr))
+#define sync_cache_r(ptr) __sync_cache_range_r(ptr, sizeof *(ptr))
+
#endif