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>

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

arch/sh/mm/cache-debugfs.c

+/*
+ * 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");