patch-2.4.21 linux-2.4.21/arch/cris/drivers/axisflashmap.c

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diff -urN linux-2.4.20/arch/cris/drivers/axisflashmap.c linux-2.4.21/arch/cris/drivers/axisflashmap.c
@@ -11,6 +11,26 @@
  * partition split defined below.
  *
  * $Log: axisflashmap.c,v $
+ * Revision 1.28  2002/10/01 08:08:43  jonashg
+ * The first partition ends at the start of the partition table.
+ *
+ * Revision 1.27  2002/08/21 09:23:13  jonashg
+ * Speling.
+ *
+ * Revision 1.26  2002/08/21 08:35:20  jonashg
+ * Cosmetic change to printouts.
+ *
+ * Revision 1.25  2002/08/21 08:15:42  jonashg
+ * Made it compile even without CONFIG_MTD_CONCAT defined.
+ *
+ * Revision 1.24  2002/08/20 13:12:35  jonashg
+ * * New approach to probing. Probe cse0 and cse1 separately and (mtd)concat
+ *   the results.
+ * * Removed compile time tests concerning how the mtdram driver has been
+ *   configured. The user will know about the misconfiguration at runtime
+ *   instead. (The old approach made it impossible to use mtdram for anything
+ *   else than RAM boot).
+ *
  * Revision 1.23  2002/05/13 12:12:28  johana
  * Allow compile without CONFIG_MTD_MTDRAM but warn at compiletime and
  * be informative at runtime.
@@ -98,13 +118,15 @@
 #include <linux/kernel.h>
 #include <linux/config.h>
 
-#include <linux/mtd/mtd.h>
+#include <linux/mtd/concat.h>
 #include <linux/mtd/map.h>
-#include <linux/mtd/partitions.h>
+#include <linux/mtd/mtd.h>
 #include <linux/mtd/mtdram.h>
+#include <linux/mtd/partitions.h>
 
 #include <asm/axisflashmap.h>
 #include <asm/mmu.h>
+#include <asm/sv_addr_ag.h>
 
 #ifdef CONFIG_CRIS_LOW_MAP
 #define FLASH_UNCACHED_ADDR  KSEG_8
@@ -114,63 +136,65 @@
 #define FLASH_CACHED_ADDR    KSEG_F
 #endif
 
-/*
- * WINDOW_SIZE is the total size where the flash chips may be mapped.
- * MTD probes should find all devices there and it does not matter
- * if there are unmapped gaps or aliases (mirrors of flash devices).
- * The MTD probes will ignore them.
- */
-
-#define WINDOW_SIZE  (128 * 1024 * 1024)
-
-extern unsigned long romfs_start, romfs_length, romfs_in_flash; /* From head.S */
+/* From head.S */
+extern unsigned long romfs_start, romfs_length, romfs_in_flash;
 
-/* 
- * Map driver
- *
- * We run into tricky coherence situations if we mix cached with uncached
- * accesses to we use the uncached version here.
- */
+/* Map driver functions. */
 
 static __u8 flash_read8(struct map_info *map, unsigned long ofs)
 {
-	return *(__u8 *)(FLASH_UNCACHED_ADDR + ofs);
+	return *(__u8 *)(map->map_priv_1 + ofs);
 }
 
 static __u16 flash_read16(struct map_info *map, unsigned long ofs)
 {
-	return *(__u16 *)(FLASH_UNCACHED_ADDR + ofs);
+	return *(__u16 *)(map->map_priv_1 + ofs);
 }
 
 static __u32 flash_read32(struct map_info *map, unsigned long ofs)
 {
-	return *(volatile unsigned int *)(FLASH_UNCACHED_ADDR + ofs);
+	return *(volatile unsigned int *)(map->map_priv_1 + ofs);
 }
 
 static void flash_copy_from(struct map_info *map, void *to,
 			    unsigned long from, ssize_t len)
 {
-	memcpy(to, (void *)(FLASH_UNCACHED_ADDR + from), len);
+	memcpy(to, (void *)(map->map_priv_1 + from), len);
 }
 
 static void flash_write8(struct map_info *map, __u8 d, unsigned long adr)
 {
-	*(__u8 *)(FLASH_UNCACHED_ADDR + adr) = d;
+	*(__u8 *)(map->map_priv_1 + adr) = d;
 }
 
 static void flash_write16(struct map_info *map, __u16 d, unsigned long adr)
 {
-	*(__u16 *)(FLASH_UNCACHED_ADDR + adr) = d;
+	*(__u16 *)(map->map_priv_1 + adr) = d;
 }
 
 static void flash_write32(struct map_info *map, __u32 d, unsigned long adr)
 {
-	*(__u32 *)(FLASH_UNCACHED_ADDR + adr) = d;
+	*(__u32 *)(map->map_priv_1 + adr) = d;
 }
 
-static struct map_info axis_map = {
-	name: "Axis flash",
-	size: WINDOW_SIZE,
+/*
+ * The map for chip select e0.
+ *
+ * We run into tricky coherence situations if we mix cached with uncached
+ * accesses to we only use the uncached version here.
+ *
+ * The size field is the total size where the flash chips may be mapped on the
+ * chip select. MTD probes should find all devices there and it does not matter
+ * if there are unmapped gaps or aliases (mirrors of flash devices). The MTD
+ * probes will ignore them.
+ *
+ * The start address in map_priv_1 is in virtual memory so we cannot use
+ * MEM_CSE0_START but must rely on that FLASH_UNCACHED_ADDR is the start
+ * address of cse0.
+ */
+static struct map_info map_cse0 = {
+	name: "cse0",
+	size: MEM_CSE0_SIZE,
 	buswidth: CONFIG_ETRAX_FLASH_BUSWIDTH,
 	read8: flash_read8,
 	read16: flash_read16,
@@ -179,15 +203,35 @@
 	write8: flash_write8,
 	write16: flash_write16,
 	write32: flash_write32,
+	map_priv_1: FLASH_UNCACHED_ADDR
 };
 
-/* If no partition-table was found, we use this default-set.
+/*
+ * The map for chip select e1.
+ *
+ * If there was a gap between cse0 and cse1, map_priv_1 would get the wrong
+ * address, but there isn't.
  */
+static struct map_info map_cse1 = {
+	name: "cse1",
+	size: MEM_CSE1_SIZE,
+	buswidth: CONFIG_ETRAX_FLASH_BUSWIDTH,
+	read8: flash_read8,
+	read16: flash_read16,
+	read32: flash_read32,
+	copy_from: flash_copy_from,
+	write8: flash_write8,
+	write16: flash_write16,
+	write32: flash_write32,
+	map_priv_1: FLASH_UNCACHED_ADDR + MEM_CSE0_SIZE
+};
 
+/* If no partition-table was found, we use this default-set. */
 #define MAX_PARTITIONS         7  
 #define NUM_DEFAULT_PARTITIONS 3
 
-/* Default flash size is 2MB. CONFIG_ETRAX_PTABLE_SECTOR is most likely the
+/*
+ * Default flash size is 2MB. CONFIG_ETRAX_PTABLE_SECTOR is most likely the
  * size of one flash block and "filesystem"-partition needs 5 blocks to be able
  * to use JFFS.
  */
@@ -209,10 +253,11 @@
 	}
 };
 
+/* Initialize the ones normally used. */
 static struct mtd_partition axis_partitions[MAX_PARTITIONS] = {
 	{
 		name: "part0",
-		size: 0,
+		size: CONFIG_ETRAX_PTABLE_SECTOR,
 		offset: 0
 	},
 	{
@@ -247,48 +292,118 @@
 	},
 };
 
+/*
+ * Probe a chip select for AMD-compatible (JEDEC) or CFI-compatible flash
+ * chips in that order (because the amd_flash-driver is faster).
+ */
+static struct mtd_info *probe_cs(struct map_info *map_cs)
+{
+	struct mtd_info *mtd_cs = NULL;
+
+	printk("%s: Probing a 0x%08lx bytes large window at 0x%08lx.\n",
+	       map_cs->name, map_cs->size, map_cs->map_priv_1);
+
+#ifdef CONFIG_MTD_AMDSTD
+	mtd_cs = do_map_probe("amd_flash", map_cs);
+#endif
+#ifdef CONFIG_MTD_CFI
+	if (!mtd_cs) {
+		mtd_cs = do_map_probe("cfi_probe", map_cs);
+	}
+#endif
+
+	return mtd_cs;
+}
+
 /* 
- * This is the master MTD device for which all the others are just
- * auto-relocating aliases.
+ * Probe each chip select individually for flash chips. If there are chips on
+ * both cse0 and cse1, the mtd_info structs will be concatenated to one struct
+ * so that MTD partitions can cross chip boundries.
+ *
+ * The only known restriction to how you can mount your chips is that each
+ * chip select must hold similar flash chips. But you need external hardware
+ * to do that anyway and you can put totally different chips on cse0 and cse1
+ * so it isn't really much of a restriction.
  */
-static struct mtd_info *mymtd;
+static struct mtd_info *flash_probe(void)
+{
+	struct mtd_info *mtd_cse0;
+	struct mtd_info *mtd_cse1;
+	struct mtd_info *mtd_cse;
+
+	mtd_cse0 = probe_cs(&map_cse0);
+	mtd_cse1 = probe_cs(&map_cse1);
+
+	if (!mtd_cse0 && !mtd_cse1) {
+		/* No chip found. */
+		return NULL;
+	}
+
+	if (mtd_cse0 && mtd_cse1) {
+#ifdef CONFIG_MTD_CONCAT
+		struct mtd_info *mtds[] = { mtd_cse0, mtd_cse1 };
+		
+		/* Since the concatenation layer adds a small overhead we
+		 * could try to figure out if the chips in cse0 and cse1 are
+		 * identical and reprobe the whole cse0+cse1 window. But since
+		 * flash chips are slow, the overhead is relatively small.
+		 * So we use the MTD concatenation layer instead of further
+		 * complicating the probing procedure.
+		 */
+		mtd_cse = mtd_concat_create(mtds,
+					    sizeof(mtds) / sizeof(mtds[0]),
+					    "cse0+cse1");
+#else
+		printk(KERN_ERR "%s and %s: Cannot concatenate due to kernel "
+		       "(mis)configuration!\n", map_cse0.name, map_cse1.name);
+		mtd_cse = NULL;
+#endif
+		if (!mtd_cse) {
+			printk(KERN_ERR "%s and %s: Concatenation failed!\n",
+			       map_cse0.name, map_cse1.name);
+
+			/* The best we can do now is to only use what we found
+			 * at cse0.
+			 */ 
+			mtd_cse = mtd_cse0;
+			map_destroy(mtd_cse1);
+		}
+	} else {
+		mtd_cse = mtd_cse0? mtd_cse0 : mtd_cse1;
+	}
+
+	return mtd_cse;
+}
 
-/* CFI-scan the flash, and if there was a chip, read the partition-table
+/*
+ * Probe the flash chip(s) and, if it succeeds, read the partition-table
  * and register the partitions with MTD.
  */
-
-static int __init
-init_axis_flash(void)
+static int __init init_axis_flash(void)
 {
+	struct mtd_info *mymtd;
 	int err = 0;
 	int pidx = 0;
 	struct partitiontable_head *ptable_head;
 	struct partitiontable_entry *ptable;
-	int use_default_ptable = 1; /* Until proven otherwise */
-	const char *pmsg = "  /dev/flash%d at 0x%x, size 0x%x\n";
-
-	printk(KERN_NOTICE "Axis flash mapping: %x at %lx\n",
-	       WINDOW_SIZE, FLASH_CACHED_ADDR);
-#ifdef CONFIG_MTD_AMDSTD
-	mymtd = (struct mtd_info *)do_map_probe("amd_flash", &axis_map);
-#endif
+	int use_default_ptable = 1; /* Until proven otherwise. */
+	const char *pmsg = "  /dev/flash%d at 0x%08x, size 0x%08x\n";
 
-#ifdef CONFIG_MTD_CFI
-	if (!mymtd) {
-		mymtd = (struct mtd_info *)do_map_probe("cfi_probe", &axis_map);
+	if (!(mymtd = flash_probe())) {
+		/* There's no reason to use this module if no flash chip can
+		 * be identified. Make sure that's understood.
+		 */
+		panic("axisflashmap found no flash chip!\n");
 	}
-#endif
 
-	if(!mymtd) {
-		printk("%s: No flash chip found!\n", axis_map.name);
-		return -ENXIO;
-	}
+	printk("%s: 0x%08x bytes of flash memory.\n",
+	       mymtd->name, mymtd->size);
 
 	mymtd->module = THIS_MODULE;
 
 	ptable_head = (struct partitiontable_head *)(FLASH_CACHED_ADDR +
-		CONFIG_ETRAX_PTABLE_SECTOR + PARTITION_TABLE_OFFSET);
-	pidx++;  /* first partition is always set to the default */
+		      CONFIG_ETRAX_PTABLE_SECTOR + PARTITION_TABLE_OFFSET);
+	pidx++;  /* First partition is always set to the default. */
 
 	if ((ptable_head->magic == PARTITION_TABLE_MAGIC)
 	    && (ptable_head->size <
@@ -322,20 +437,17 @@
 			csum += *p++;
 			csum += *p++;
 		}
-		/* printk("  total csum: 0x%08X 0x%08X\n",
-		   csum, ptable_head->checksum); */
 		ptable_ok = (csum == ptable_head->checksum);
 
 		/* Read the entries and use/show the info.  */
-		printk(" Found %s partition table at 0x%08lX-0x%08lX.\n",
-		       (ptable_ok ? "valid" : "invalid"),
-		       (unsigned long)ptable_head,
-		       (unsigned long)max_addr);
+		printk(" Found a%s partition table at 0x%p-0x%p.\n",
+		       (ptable_ok ? " valid" : "n invalid"), ptable_head,
+		       max_addr);
 
 		/* We have found a working bootblock.  Now read the
-		   partition table.  Scan the table.  It ends when
-		   there is 0xffffffff, that is, empty flash.  */
-		
+		 * partition table.  Scan the table.  It ends when
+		 * there is 0xffffffff, that is, empty flash.
+		 */
 		while (ptable_ok
 		       && ptable->offset != 0xffffffff
 		       && ptable < max_addr
@@ -352,59 +464,64 @@
 		use_default_ptable = !ptable_ok;
 	}
 
+	if (romfs_in_flash) {
+		/* Add an overlapping device for the root partition (romfs). */
+
+		axis_partitions[pidx].name = "romfs";
+		axis_partitions[pidx].size = romfs_length;
+		axis_partitions[pidx].offset = romfs_start - FLASH_CACHED_ADDR;
+		axis_partitions[pidx].mask_flags |= MTD_WRITEABLE;
+
+		printk(" Adding readonly flash partition for romfs image:\n");
+		printk(pmsg, pidx, axis_partitions[pidx].offset,
+		       axis_partitions[pidx].size);
+		pidx++;
+	}
+
 	if (use_default_ptable) {
-		printk(" Using default partition table\n");
+		printk(" Using default partition table.\n");
 		err = add_mtd_partitions(mymtd, axis_default_partitions,
 		                         NUM_DEFAULT_PARTITIONS);
 	} else {
-		if (romfs_in_flash) {
-			axis_partitions[pidx].name = "romfs";
-			axis_partitions[pidx].size = romfs_length;
-			axis_partitions[pidx].offset = romfs_start -
-						       FLASH_CACHED_ADDR;
-			axis_partitions[pidx].mask_flags |= MTD_WRITEABLE;
-
-			printk(" Adding readonly partition for romfs image:\n");
-			printk(pmsg, pidx, axis_partitions[pidx].offset,
-			       axis_partitions[pidx].size);
-			pidx++;
-		}
-
 		err = add_mtd_partitions(mymtd, axis_partitions, pidx);
 	}
-	if (!err && !romfs_in_flash) {
-#ifdef CONFIG_MTD_MTDRAM
-		/* Allocate, initialise and forget the mtd ram struct
-		 * when booting from RAM
-		 */
-		struct mtd_info *romfs_mtd = (struct mtd_info *)kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
-		printk("MTD RAM device romfs_start: 0x%08lX len %lu\n",
-		       romfs_start, romfs_length);
 
-#if (CONFIG_MTDRAM_TOTAL_SIZE != 0) || (CONFIG_MTDRAM_ABS_POS != 0)
-#error "You must set CONFIG_MTDRAM_TOTAL_SIZE and CONFIG_MTDRAM_ABS_POS to 0"
-#endif
-		err = mtdram_init_device(romfs_mtd, (void*)romfs_start, 
-		                         romfs_length, "romfs in RAM");
+	if (err) {
+		panic("axisflashmap could not add MTD partitions!\n");
+	}
+
+	if (!romfs_in_flash) {
+		/* Create an RAM device for the root partition (romfs). */
+
+#if !defined(CONFIG_MTD_MTDRAM) || (CONFIG_MTDRAM_TOTAL_SIZE != 0) || (CONFIG_MTDRAM_ABS_POS != 0)
+		/* No use trying to boot this kernel from RAM. Panic! */
+		printk(KERN_EMERG "axisflashmap: Cannot create an MTD RAM "
+		       "device due to kernel (mis)configuration!\n");
+		panic("This kernel cannot boot from RAM!\n");
 #else
-#warning ######################################
-#warning # You must enable CONFIG_MTD_MTDRAM  #
-#warning # with TOTAL_SIZE 0 and ABS_POS 0 to # 
-#warning # be able to boot with cramfs in RAM #
-#warning ######################################
-/* Maybe overkill to save these bytes in non debug builds, but let's do it..
- * (No point in printing if we don't have a debug port anyway...)
- */
-#ifndef CONFIG_ETRAX_DEBUG_PORT_NULL
-		printk("## Can't mount romfs in RAM using MTDRAM.\n");
-		printk("## You must enable MTD_MTDRAM with TOTAL_SIZE 0 and ABS_POS 0\n");
+		struct mtd_info *mtd_ram;
+
+		mtd_ram = (struct mtd_info *)kmalloc(sizeof(struct mtd_info),
+						     GFP_KERNEL);
+		if (!mtd_ram) {
+			panic("axisflashmap couldn't allocate memory for "
+			      "mtd_info!\n");
+		}
+
+		printk(" Adding RAM partition for romfs image:\n");
+		printk(pmsg, pidx, romfs_start, romfs_length);
+
+		err = mtdram_init_device(mtd_ram, (void*)romfs_start, 
+		                         romfs_length, "romfs");
+		if (err) {
+			panic("axisflashmap could not initialize MTD RAM "
+			      "device!\n");
+		}
 #endif
-#endif /* CONFIG_MTD_MTDRAM */
 	}
+
 	return err;
 }
 
-/* This adds the above to the kernels init-call chain */
-
+/* This adds the above to the kernels init-call chain. */
 module_init(init_axis_flash);
-
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