sh: Add support for cacheline poking through debugfs.

A simple debugging aid for easier visibility of the respective
cachelines.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

2 files changed, 151 insertions, 0 deletions

diff --git a/arch/sh/mm/Makefile b/arch/sh/mm/Makefile
index da37d86e65eb..3ffd7f68c0a2 100644
--- a/arch/sh/mm/Makefile
+++ b/arch/sh/mm/Makefile
@@ -17,6 +17,10 @@ mmu-$(CONFIG_MMU)	:= fault.o clear_page.o copy_page.o tlb-flush.o	\
 
 obj-y                   += $(mmu-y)
 
+ifdef CONFIG_DEBUG_FS
+obj-$(CONFIG_CPU_SH4)           += cache-debugfs.o
+endif
+
 ifdef CONFIG_MMU
 obj-$(CONFIG_CPU_SH3)           += tlb-sh3.o
 obj-$(CONFIG_CPU_SH4)           += tlb-sh4.o pg-sh4.o
diff --git a/arch/sh/mm/cache-debugfs.c b/arch/sh/mm/cache-debugfs.c
new file mode 100644
index 000000000000..a22d914e4d15
--- /dev/null
+++ b/arch/sh/mm/cache-debugfs.c
@@ -0,0 +1,147 @@
+/*
+ * debugfs ops for the L1 cache
+ *
+ *  Copyright (C) 2006  Paul Mundt
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <asm/processor.h>
+#include <asm/uaccess.h>
+#include <asm/cache.h>
+#include <asm/io.h>
+
+enum cache_type {
+        CACHE_TYPE_ICACHE,
+        CACHE_TYPE_DCACHE,
+        CACHE_TYPE_UNIFIED,
+};
+
+static int cache_seq_show(struct seq_file *file, void *iter)
+{
+        unsigned int cache_type = (unsigned int)file->private;
+        struct cache_info *cache;
+        unsigned int waysize, way, cache_size;
+        unsigned long ccr, base;
+        static unsigned long addrstart = 0;
+
+        /*
+         * Go uncached immediately so we don't skew the results any
+         * more than we already are..
+         */
+        jump_to_P2();
+
+        ccr = ctrl_inl(CCR);
+        if ((ccr & CCR_CACHE_ENABLE) == 0) {
+                back_to_P1();
+
+                seq_printf(file, "disabled\n");
+                return 0;
+        }
+
+        if (cache_type == CACHE_TYPE_DCACHE) {
+                base = CACHE_OC_ADDRESS_ARRAY;
+                cache = &cpu_data->dcache;
+        } else {
+                base = CACHE_IC_ADDRESS_ARRAY;
+                cache = &cpu_data->icache;
+        }
+
+        /*
+         * Due to the amount of data written out (depending on the cache size),
+         * we may be iterated over multiple times. In this case, keep track of
+         * the entry position in addrstart, and rewind it when we've hit the
+         * end of the cache.
+         *
+         * Likewise, the same code is used for multiple caches, so care must
+         * be taken for bouncing addrstart back and forth so the appropriate
+         * cache is hit.
+         */
+        cache_size = cache->ways * cache->sets * cache->linesz;
+        if (((addrstart & 0xff000000) != base) ||
+             (addrstart & 0x00ffffff) > cache_size)
+                addrstart = base;
+
+        waysize = cache->sets;
+
+        /*
+         * If the OC is already in RAM mode, we only have
+         * half of the entries to consider..
+         */
+        if ((ccr & CCR_CACHE_ORA) && cache_type == CACHE_TYPE_DCACHE)
+                waysize >>= 1;
+
+        waysize <<= cache->entry_shift;
+
+        for (way = 0; way < cache->ways; way++) {
+                unsigned long addr;
+                unsigned int line;
+
+                seq_printf(file, "-----------------------------------------\n");
+                seq_printf(file, "Way %d\n", way);
+                seq_printf(file, "-----------------------------------------\n");
+
+                for (addr = addrstart, line = 0;
+                     addr < addrstart + waysize;
+                     addr += cache->linesz, line++) {
+                        unsigned long data = ctrl_inl(addr);
+
+                        /* Check the V bit, ignore invalid cachelines */
+                        if ((data & 1) == 0)
+                                continue;
+
+                        /* U: Dirty, cache tag is 10 bits up */
+                        seq_printf(file, "%3d: %c 0x%lx\n",
+                                   line, data & 2 ? 'U' : ' ',
+                                   data & 0x1ffffc00);
+                }
+
+                addrstart += cache->way_incr;
+        }
+
+        back_to_P1();
+
+        return 0;
+}
+
+static int cache_debugfs_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, cache_seq_show, inode->u.generic_ip);
+}
+
+static struct file_operations cache_debugfs_fops = {
+        .owner          = THIS_MODULE,
+        .open           = cache_debugfs_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = seq_release,
+};
+
+static int __init cache_debugfs_init(void)
+{
+        struct dentry *dcache_dentry, *icache_dentry;
+
+        dcache_dentry = debugfs_create_file("dcache", S_IRUSR, NULL,
+                                            (unsigned int *)CACHE_TYPE_DCACHE,
+                                            &cache_debugfs_fops);
+        if (IS_ERR(dcache_dentry))
+                return PTR_ERR(dcache_dentry);
+
+        icache_dentry = debugfs_create_file("icache", S_IRUSR, NULL,
+                                            (unsigned int *)CACHE_TYPE_ICACHE,
+                                            &cache_debugfs_fops);
+        if (IS_ERR(icache_dentry)) {
+                debugfs_remove(dcache_dentry);
+                return PTR_ERR(icache_dentry);
+        }
+
+        return 0;
+}
+module_init(cache_debugfs_init);
+
+MODULE_LICENSE("GPL v2");