MTD: Provide XIP support for Intel flash chips.

This allows for MTD support to be used on flash memory which is also used
for XIP purposes, either XIP kernel or XIP userspace.  The whole idea is
to relocate functions actually modifying the flash state away from array mode
to ram and run them with interrupt disabled.  When the flash needs some time
to complete a certain operation, we poll the processor for pending (but still
masked) interrupts, and when they occur we suspend the flash operation in order
to unmask interrupts and let the system run again.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

drivers/mtd/chips/Kconfig

 # drivers/mtd/chips/Kconfig
-# $Id: Kconfig,v 1.9 2004/07/16 15:32:14 dwmw2 Exp $
+# $Id: Kconfig,v 1.10 2004/11/05 22:41:04 nico Exp $
 
 menu "RAM/ROM/Flash chip drivers"
 	depends on MTD!=n
@@ -272,5 +272,14 @@ config MTD_JEDEC
 	  <http://www.jedec.org/> distributes the identification codes for the
 	  chips.
 
+config MTD_XIP
+	bool "XIP aware MTD support"
+	depends on !SMP && MTD_CFI_INTELEXT && EXPERIMENTAL
+	default y if XIP_KERNEL
+	help
+	  This allows MTD support to work with flash memory which is also
+	  used for XIP purposes.  If you're not sure what this is all about
+	  then say N.
+
 endmenu
 

drivers/mtd/chips/cfi_cmdset_0001.c

@@ -4,9 +4,8 @@
  *
  * (C) 2000 Red Hat. GPL'd
  *
- * $Id: cfi_cmdset_0001.c,v 1.160 2004/11/01 06:02:24 nico Exp $
- * (+ suspend fix from v1.162)
- * (+ partition detection fix from v1.163)
+ * $Id: cfi_cmdset_0001.c,v 1.164 2004/11/16 18:29:00 dwmw2 Exp $
+ *
  * 
  * 10/10/2000	Nicolas Pitre <nico@cam.org>
  * 	- completely revamped method functions so they are aware and
@@ -30,6 +29,7 @@
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
+#include <linux/mtd/xip.h>
 #include <linux/mtd/map.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/compatmac.h>
@@ -37,6 +37,10 @@
 
 /* #define CMDSET0001_DISABLE_ERASE_SUSPEND_ON_WRITE */
 
+#ifdef CONFIG_MTD_XIP
+#define CMDSET0001_DISABLE_WRITE_SUSPEND
+#endif
+
 // debugging, turns off buffer write mode if set to 1
 #define FORCE_WORD_WRITE 0
 
@@ -147,6 +151,21 @@ static void fixup_intel_strataflash(struct mtd_info *mtd, void* param)
 }
 #endif
 
+#ifdef CMDSET0001_DISABLE_WRITE_SUSPEND
+/* The XIP config appears to have problems using write suspend at the moment */ 
+static void fixup_no_write_suspend(struct mtd_info *mtd, void* param)
+{
+	struct map_info *map = mtd->priv;
+	struct cfi_private *cfi = map->fldrv_priv;
+	struct cfi_pri_intelext *cfip = cfi->cmdset_priv;
+
+	if (cfip && (cfip->FeatureSupport&4)) {
+		cfip->FeatureSupport &= ~4;
+		printk(KERN_WARNING "cfi_cmdset_0001: write suspend disabled\n");
+	}
+}
+#endif
+
 static void fixup_st_m28w320ct(struct mtd_info *mtd, void* param)
 {
 	struct map_info *map = mtd->priv;
@@ -189,6 +208,9 @@ static struct cfi_fixup cfi_fixup_table[] = {
 #ifdef CMDSET0001_DISABLE_ERASE_SUSPEND_ON_WRITE
 	{ CFI_MFR_ANY, CFI_ID_ANY, fixup_intel_strataflash, NULL }, 
 #endif
+#ifdef CMDSET0001_DISABLE_WRITE_SUSPEND
+	{ CFI_MFR_ANY, CFI_ID_ANY, fixup_no_write_suspend, NULL },
+#endif
 #if !FORCE_WORD_WRITE
 	{ CFI_MFR_ANY, CFI_ID_ANY, fixup_use_write_buffers, NULL },
 #endif
@@ -679,6 +701,14 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr
 		chip->state = FL_STATUS;
 		return 0;
 
+	case FL_XIP_WHILE_ERASING:
+		if (mode != FL_READY && mode != FL_POINT &&
+		    (mode != FL_WRITING || !cfip || !(cfip->SuspendCmdSupport&1)))
+			goto sleep;
+		chip->oldstate = chip->state;
+		chip->state = FL_READY;
+		return 0;
+
 	case FL_POINT:
 		/* Only if there's no operation suspended... */
 		if (mode == FL_READY && chip->oldstate == FL_READY)
@@ -746,6 +776,11 @@ static void put_chip(struct map_info *map, struct flchip *chip, unsigned long ad
 		chip->state = FL_ERASING;
 		break;
 
+	case FL_XIP_WHILE_ERASING:
+		chip->state = chip->oldstate;
+		chip->oldstate = FL_READY;
+		break;
+
 	case FL_READY:
 	case FL_STATUS:
 	case FL_JEDEC_QUERY:
@@ -758,6 +793,201 @@ static void put_chip(struct map_info *map, struct flchip *chip, unsigned long ad
 	wake_up(&chip->wq);
 }
 
+#ifdef CONFIG_MTD_XIP
+
+/*
+ * No interrupt what so ever can be serviced while the flash isn't in array
+ * mode.  This is ensured by the xip_disable() and xip_enable() functions
+ * enclosing any code path where the flash is known not to be in array mode.
+ * And within a XIP disabled code path, only functions marked with __xipram
+ * may be called and nothing else (it's a good thing to inspect generated
+ * assembly to make sure inline functions were actually inlined and that gcc
+ * didn't emit calls to its own support functions). Also configuring MTD CFI
+ * support to a single buswidth and a single interleave is also recommended.
+ * Note that not only IRQs are disabled but the preemption count is also
+ * increased to prevent other locking primitives (namely spin_unlock) from
+ * decrementing the preempt count to zero and scheduling the CPU away while
+ * not in array mode.
+ */
+
+static void xip_disable(struct map_info *map, struct flchip *chip,
+			unsigned long adr)
+{
+	/* TODO: chips with no XIP use should ignore and return */
+	(void) map_read(map, adr); /* ensure mmu mapping is up to date */
+	preempt_disable();
+	local_irq_disable();
+}
+
+static void __xipram xip_enable(struct map_info *map, struct flchip *chip,
+				unsigned long adr)
+{
+	struct cfi_private *cfi = map->fldrv_priv;
+	if (chip->state != FL_POINT && chip->state != FL_READY) {
+		map_write(map, CMD(0xff), adr);
+		chip->state = FL_READY;
+	}
+	(void) map_read(map, adr);
+	asm volatile (".rep 8; nop; .endr"); /* fill instruction prefetch */
+	local_irq_enable();
+	preempt_enable();
+}
+
+/*
+ * When a delay is required for the flash operation to complete, the
+ * xip_udelay() function is polling for both the given timeout and pending
+ * (but still masked) hardware interrupts.  Whenever there is an interrupt
+ * pending then the flash erase or write operation is suspended, array mode
+ * restored and interrupts unmasked.  Task scheduling might also happen at that
+ * point.  The CPU eventually returns from the interrupt or the call to
+ * schedule() and the suspended flash operation is resumed for the remaining
+ * of the delay period.
+ *
+ * Warning: this function _will_ fool interrupt latency tracing tools.
+ */
+
+static void __xipram xip_udelay(struct map_info *map, struct flchip *chip,
+				unsigned long adr, int usec)
+{
+	struct cfi_private *cfi = map->fldrv_priv;
+	struct cfi_pri_intelext *cfip = cfi->cmdset_priv;
+	map_word status, OK = CMD(0x80);
+	unsigned long suspended, start = xip_currtime();
+	flstate_t oldstate, newstate;
+
+	do {
+		cpu_relax();
+		if (xip_irqpending() && cfip &&
+		    ((chip->state == FL_ERASING && (cfip->FeatureSupport&2)) ||
+		     (chip->state == FL_WRITING && (cfip->FeatureSupport&4))) &&
+		    (cfi_interleave_is_1(cfi) || chip->oldstate == FL_READY)) {
+			/*
+			 * Let's suspend the erase or write operation when
+			 * supported.  Note that we currently don't try to
+			 * suspend interleaved chips if there is already
+			 * another operation suspended (imagine what happens
+			 * when one chip was already done with the current
+			 * operation while another chip suspended it, then
+			 * we resume the whole thing at once).  Yes, it
+			 * can happen!
+			 */
+			map_write(map, CMD(0xb0), adr);
+			map_write(map, CMD(0x70), adr);
+			usec -= xip_elapsed_since(start);
+			suspended = xip_currtime();
+			do {
+				if (xip_elapsed_since(suspended) > 100000) {
+					/*
+					 * The chip doesn't want to suspend
+					 * after waiting for 100 msecs.
+					 * This is a critical error but there
+					 * is not much we can do here.
+					 */
+					return;
+				}
+				status = map_read(map, adr);
+			} while (!map_word_andequal(map, status, OK, OK));
+
+			/* Suspend succeeded */
+			oldstate = chip->state;
+			if (oldstate == FL_ERASING) {
+				if (!map_word_bitsset(map, status, CMD(0x40)))
+					break;
+				newstate = FL_XIP_WHILE_ERASING;
+				chip->erase_suspended = 1;
+			} else {
+				if (!map_word_bitsset(map, status, CMD(0x04)))
+					break;
+				newstate = FL_XIP_WHILE_WRITING;
+				chip->write_suspended = 1;
+			}
+			chip->state = newstate;
+			map_write(map, CMD(0xff), adr);
+			(void) map_read(map, adr);
+			asm volatile (".rep 8; nop; .endr");
+			local_irq_enable();
+			preempt_enable();
+			asm volatile (".rep 8; nop; .endr");
+			cond_resched();
+
+			/*
+			 * We're back.  However someone else might have
+			 * decided to go write to the chip if we are in
+			 * a suspended erase state.  If so let's wait
+			 * until it's done.
+			 */
+			preempt_disable();
+			while (chip->state != newstate) {
+				DECLARE_WAITQUEUE(wait, current);
+				set_current_state(TASK_UNINTERRUPTIBLE);
+				add_wait_queue(&chip->wq, &wait);
+				preempt_enable();
+				schedule();
+				remove_wait_queue(&chip->wq, &wait);
+				preempt_disable();
+			}
+			/* Disallow XIP again */
+			local_irq_disable();
+
+			/* Resume the write or erase operation */
+			map_write(map, CMD(0xd0), adr);
+			map_write(map, CMD(0x70), adr);
+			chip->state = oldstate;
+			start = xip_currtime();
+		} else if (usec >= 1000000/HZ) {
+			/*
+			 * Try to save on CPU power when waiting delay
+			 * is at least a system timer tick period.
+			 * No need to be extremely accurate here.
+			 */
+			xip_cpu_idle();
+		}
+		status = map_read(map, adr);
+	} while (!map_word_andequal(map, status, OK, OK)
+		 && xip_elapsed_since(start) < usec);
+}
+
+#define UDELAY(map, chip, adr, usec)  xip_udelay(map, chip, adr, usec)
+
+/*
+ * The INVALIDATE_CACHED_RANGE() macro is normally used in parallel while
+ * the flash is actively programming or erasing since we have to poll for
+ * the operation to complete anyway.  We can't do that in a generic way with
+ * a XIP setup so do it before the actual flash operation in this case.
+ */
+#undef INVALIDATE_CACHED_RANGE
+#define INVALIDATE_CACHED_RANGE(x...)
+#define XIP_INVAL_CACHED_RANGE(map, from, size) \
+	do { if(map->inval_cache) map->inval_cache(map, from, size); } while(0)
+
+/*
+ * Extra notes:
+ *
+ * Activating this XIP support changes the way the code works a bit.  For
+ * example the code to suspend the current process when concurrent access
+ * happens is never executed because xip_udelay() will always return with the
+ * same chip state as it was entered with.  This is why there is no care for
+ * the presence of add_wait_queue() or schedule() calls from within a couple
+ * xip_disable()'d  areas of code, like in do_erase_oneblock for example.
+ * The queueing and scheduling are always happening within xip_udelay().
+ *
+ * Similarly, get_chip() and put_chip() just happen to always be executed
+ * with chip->state set to FL_READY (or FL_XIP_WHILE_*) where flash state
+ * is in array mode, therefore never executing many cases therein and not
+ * causing any problem with XIP.
+ */
+
+#else
+
+#define xip_disable(map, chip, adr)
+#define xip_enable(map, chip, adr)
+
+#define UDELAY(map, chip, adr, usec)  cfi_udelay(usec)
+
+#define XIP_INVAL_CACHED_RANGE(x...)
+
+#endif
+
 static int do_point_onechip (struct map_info *map, struct flchip *chip, loff_t adr, size_t len)
 {
 	unsigned long cmd_addr;
@@ -944,7 +1174,11 @@ static int cfi_intelext_read (struct mtd_info *mtd, loff_t from, size_t len, siz
 }
 
 #if 0
-static int cfi_intelext_read_prot_reg (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf, int base_offst, int reg_sz)
+static int __xipram cfi_intelext_read_prot_reg (struct mtd_info *mtd,
+						loff_t from, size_t len,
+						size_t *retlen,
+						u_char *buf,
+						int base_offst, int reg_sz)
 {
 	struct map_info *map = mtd->priv;
 	struct cfi_private *cfi = map->fldrv_priv;
@@ -973,6 +1207,8 @@ static int cfi_intelext_read_prot_reg (struct mtd_info *mtd, loff_t from, size_t
 			return (len-count)?:ret;
 		}
 
+		xip_disable(map, chip, chip->start);
+
 		if (chip->state != FL_JEDEC_QUERY) {
 			map_write(map, CMD(0x90), chip->start);
 			chip->state = FL_JEDEC_QUERY;
@@ -985,6 +1221,7 @@ static int cfi_intelext_read_prot_reg (struct mtd_info *mtd, loff_t from, size_t
 			count--;
 		}
 
+		xip_enable(map, chip, chip->start);
 		put_chip(map, chip, chip->start);
 		spin_unlock(chip->mutex);
 
@@ -1036,7 +1273,8 @@ static int cfi_intelext_read_fact_prot_reg (struct mtd_info *mtd, loff_t from, s
 }
 #endif
 
-static int do_write_oneword(struct map_info *map, struct flchip *chip, unsigned long adr, map_word datum)
+static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip,
+				     unsigned long adr, map_word datum)
 {
 	struct cfi_private *cfi = map->fldrv_priv;
 	map_word status, status_OK;
@@ -1055,14 +1293,16 @@ static int do_write_oneword(struct map_info *map, struct flchip *chip, unsigned
 		return ret;
 	}
 
+	XIP_INVAL_CACHED_RANGE(map, adr, map_bankwidth(map));
 	ENABLE_VPP(map);
+	xip_disable(map, chip, adr);
 	map_write(map, CMD(0x40), adr);
 	map_write(map, datum, adr);
 	chip->state = FL_WRITING;
 
 	spin_unlock(chip->mutex);
 	INVALIDATE_CACHED_RANGE(map, adr, map_bankwidth(map));
-	cfi_udelay(chip->word_write_time);
+	UDELAY(map, chip, adr, chip->word_write_time);
 	spin_lock(chip->mutex);
 
 	timeo = jiffies + (HZ/2);
@@ -1089,6 +1329,7 @@ static int do_write_oneword(struct map_info *map, struct flchip *chip, unsigned
 		/* OK Still waiting */
 		if (time_after(jiffies, timeo)) {
 			chip->state = FL_STATUS;
+			xip_enable(map, chip, adr);
 			printk(KERN_ERR "waiting for chip to be ready timed out in word write\n");
 			ret = -EIO;
 			goto out;
@@ -1097,7 +1338,7 @@ static int do_write_oneword(struct map_info *map, struct flchip *chip, unsigned
 		/* Latency issues. Drop the lock, wait a while and retry */
 		spin_unlock(chip->mutex);
 		z++;
-		cfi_udelay(1);
+		UDELAY(map, chip, adr, 1);
 		spin_lock(chip->mutex);
 	}
 	if (!z) {
@@ -1119,8 +1360,9 @@ static int do_write_oneword(struct map_info *map, struct flchip *chip, unsigned
 		map_write(map, CMD(0x70), adr);
 		ret = -EROFS;
 	}
- out:
-	put_chip(map, chip, adr);
+
+	xip_enable(map, chip, adr);
+ out:	put_chip(map, chip, adr);
 	spin_unlock(chip->mutex);
 
 	return ret;
@@ -1210,7 +1452,7 @@ static int cfi_intelext_write_words (struct mtd_info *mtd, loff_t to , size_t le
 }
 
 
-static inline int do_write_buffer(struct map_info *map, struct flchip *chip, 
+static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip, 
 				    unsigned long adr, const u_char *buf, int len)
 {
 	struct cfi_private *cfi = map->fldrv_priv;
@@ -1232,6 +1474,10 @@ static inline int do_write_buffer(struct map_info *map, struct flchip *chip,
 		return ret;
 	}
 
+	XIP_INVAL_CACHED_RANGE(map, adr, len);
+	ENABLE_VPP(map);
+	xip_disable(map, chip, cmd_adr);
+
 	/* 4.8 of the 28FxxxJ3A datasheet says "Any time SR.4 and/or SR.5 is set
 	   [...], the device will not accept any more Write to Buffer commands". 
 	   So we must check here and reset those bits if they're set. Otherwise
@@ -1240,12 +1486,13 @@ static inline int do_write_buffer(struct map_info *map, struct flchip *chip,
 		map_write(map, CMD(0x70), cmd_adr);
 	status = map_read(map, cmd_adr);
 	if (map_word_bitsset(map, status, CMD(0x30))) {
+		xip_enable(map, chip, cmd_adr);
 		printk(KERN_WARNING "SR.4 or SR.5 bits set in buffer write (status %lx). Clearing.\n", status.x[0]);
+		xip_disable(map, chip, cmd_adr);
 		map_write(map, CMD(0x50), cmd_adr);
 		map_write(map, CMD(0x70), cmd_adr);
 	}
 
-	ENABLE_VPP(map);
 	chip->state = FL_WRITING_TO_BUFFER;
 
 	z = 0;
@@ -1257,7 +1504,7 @@ static inline int do_write_buffer(struct map_info *map, struct flchip *chip,
 			break;
 
 		spin_unlock(chip->mutex);
-		cfi_udelay(1);
+		UDELAY(map, chip, cmd_adr, 1);
 		spin_lock(chip->mutex);
 
 		if (++z > 20) {
@@ -1269,6 +1516,7 @@ static inline int do_write_buffer(struct map_info *map, struct flchip *chip,
 			/* Odd. Clear status bits */
 			map_write(map, CMD(0x50), cmd_adr);
 			map_write(map, CMD(0x70), cmd_adr);
+			xip_enable(map, chip, cmd_adr);
 			printk(KERN_ERR "Chip not ready for buffer write. status = %lx, Xstatus = %lx\n",
 			       status.x[0], Xstatus.x[0]);
 			ret = -EIO;
@@ -1305,7 +1553,7 @@ static inline int do_write_buffer(struct map_info *map, struct flchip *chip,
 
 	spin_unlock(chip->mutex);
 	INVALIDATE_CACHED_RANGE(map, adr, len);
-	cfi_udelay(chip->buffer_write_time);
+	UDELAY(map, chip, cmd_adr, chip->buffer_write_time);
 	spin_lock(chip->mutex);
 
 	timeo = jiffies + (HZ/2);
@@ -1331,6 +1579,7 @@ static inline int do_write_buffer(struct map_info *map, struct flchip *chip,
 		/* OK Still waiting */
 		if (time_after(jiffies, timeo)) {
 			chip->state = FL_STATUS;
+			xip_enable(map, chip, cmd_adr);
 			printk(KERN_ERR "waiting for chip to be ready timed out in bufwrite\n");
 			ret = -EIO;
 			goto out;
@@ -1338,7 +1587,7 @@ static inline int do_write_buffer(struct map_info *map, struct flchip *chip,
 		
 		/* Latency issues. Drop the lock, wait a while and retry */
 		spin_unlock(chip->mutex);
-		cfi_udelay(1);
+		UDELAY(map, chip, cmd_adr, 1);
 		z++;
 		spin_lock(chip->mutex);
 	}
@@ -1362,8 +1611,8 @@ static inline int do_write_buffer(struct map_info *map, struct flchip *chip,
 		ret = -EROFS;
 	}
 
- out:
-	put_chip(map, chip, cmd_adr);
+	xip_enable(map, chip, cmd_adr);
+ out:	put_chip(map, chip, cmd_adr);
 	spin_unlock(chip->mutex);
 	return ret;
 }
@@ -1432,7 +1681,7 @@ static int cfi_intelext_write_buffers (struct mtd_info *mtd, loff_t to,
 	return 0;
 }
 
-static int do_erase_oneblock(struct map_info *map, struct flchip *chip,
+static int __xipram do_erase_oneblock(struct map_info *map, struct flchip *chip,
 				      unsigned long adr, int len, void *thunk)
 {
 	struct cfi_private *cfi = map->fldrv_priv;
@@ -1455,7 +1704,10 @@ static int do_erase_oneblock(struct map_info *map, struct flchip *chip,
 		return ret;
 	}
 
+	XIP_INVAL_CACHED_RANGE(map, adr, len);
 	ENABLE_VPP(map);
+	xip_disable(map, chip, adr);
+
 	/* Clear the status register first */
 	map_write(map, CMD(0x50), adr);
 
@@ -1467,7 +1719,7 @@ static int do_erase_oneblock(struct map_info *map, struct flchip *chip,
 
 	spin_unlock(chip->mutex);
 	INVALIDATE_CACHED_RANGE(map, adr, len);
-	msleep(chip->erase_time / 2);
+	UDELAY(map, chip, adr, chip->erase_time*1000/2);
 	spin_lock(chip->mutex);
 
 	/* FIXME. Use a timer to check this, and return immediately. */
@@ -1505,6 +1757,7 @@ static int do_erase_oneblock(struct map_info *map, struct flchip *chip,
 			/* Clear status bits */
 			map_write(map, CMD(0x50), adr);
 			map_write(map, CMD(0x70), adr);
+			xip_enable(map, chip, adr);
 			printk(KERN_ERR "waiting for erase at %08lx to complete timed out. status = %lx, Xstatus = %lx.\n",
 			       adr, status.x[0], Xstatus.x[0]);
 			ret = -EIO;
@@ -1513,8 +1766,7 @@ static int do_erase_oneblock(struct map_info *map, struct flchip *chip,
 		
 		/* Latency issues. Drop the lock, wait a while and retry */
 		spin_unlock(chip->mutex);
-		set_current_state(TASK_UNINTERRUPTIBLE);
-		schedule_timeout(1);
+		UDELAY(map, chip, adr, 1000000/HZ);
 		spin_lock(chip->mutex);
 	}
 
@@ -1530,6 +1782,7 @@ static int do_erase_oneblock(struct map_info *map, struct flchip *chip,
 		/* Reset the error bits */
 		map_write(map, CMD(0x50), adr);
 		map_write(map, CMD(0x70), adr);
+		xip_enable(map, chip, adr);
 
 		chipstatus = status.x[0];
 		if (!map_word_equal(map, status, CMD(chipstatus))) {
@@ -1565,6 +1818,7 @@ static int do_erase_oneblock(struct map_info *map, struct flchip *chip,
 			ret = -EIO;
 		}
 	} else {
+		xip_enable(map, chip, adr);
 		ret = 0;
 	}
 
@@ -1632,15 +1886,19 @@ static void cfi_intelext_sync (struct mtd_info *mtd)
 }
 
 #ifdef DEBUG_LOCK_BITS
-static int do_printlockstatus_oneblock(struct map_info *map, struct flchip *chip,
-				       unsigned long adr, int len, void *thunk)
+static int __xipram do_printlockstatus_oneblock(struct map_info *map,
+						struct flchip *chip,
+						unsigned long adr,
+						int len, void *thunk)
 {
 	struct cfi_private *cfi = map->fldrv_priv;
 	int status, ofs_factor = cfi->interleave * cfi->device_type;
 
+	xip_disable(map, chip, adr+(2*ofs_factor));
 	cfi_send_gen_cmd(0x90, 0x55, 0, map, cfi, cfi->device_type, NULL);
 	chip->state = FL_JEDEC_QUERY;
 	status = cfi_read_query(map, adr+(2*ofs_factor));
+	xip_enable(map, chip, 0);
 	printk(KERN_DEBUG "block status register for 0x%08lx is %x\n",
 	       adr, status);
 	return 0;
@@ -1650,7 +1908,7 @@ static int do_printlockstatus_oneblock(struct map_info *map, struct flchip *chip
 #define DO_XXLOCK_ONEBLOCK_LOCK		((void *) 1)
 #define DO_XXLOCK_ONEBLOCK_UNLOCK	((void *) 2)
 
-static int do_xxlock_oneblock(struct map_info *map, struct flchip *chip,
+static int __xipram do_xxlock_oneblock(struct map_info *map, struct flchip *chip,
 				       unsigned long adr, int len, void *thunk)
 {
 	struct cfi_private *cfi = map->fldrv_priv;
@@ -1671,8 +1929,9 @@ static int do_xxlock_oneblock(struct map_info *map, struct flchip *chip,
 	}
 
 	ENABLE_VPP(map);
-	map_write(map, CMD(0x60), adr);
+	xip_disable(map, chip, adr);
 	
+	map_write(map, CMD(0x60), adr);
 	if (thunk == DO_XXLOCK_ONEBLOCK_LOCK) {
 		map_write(map, CMD(0x01), adr);
 		chip->state = FL_LOCKING;
@@ -1683,7 +1942,7 @@ static int do_xxlock_oneblock(struct map_info *map, struct flchip *chip,
 		BUG();
 
 	spin_unlock(chip->mutex);
-	schedule_timeout(HZ);
+	UDELAY(map, chip, adr, 1000000/HZ);
 	spin_lock(chip->mutex);
 
 	/* FIXME. Use a timer to check this, and return immediately. */
@@ -1702,6 +1961,7 @@ static int do_xxlock_oneblock(struct map_info *map, struct flchip *chip,
 			map_write(map, CMD(0x70), adr);
 			chip->state = FL_STATUS;
 			Xstatus = map_read(map, adr);
+			xip_enable(map, chip, adr);
 			printk(KERN_ERR "waiting for unlock to complete timed out. status = %lx, Xstatus = %lx.\n",
 			       status.x[0], Xstatus.x[0]);
 			put_chip(map, chip, adr);
@@ -1711,12 +1971,13 @@ static int do_xxlock_oneblock(struct map_info *map, struct flchip *chip,
 		
 		/* Latency issues. Drop the lock, wait a while and retry */
 		spin_unlock(chip->mutex);
-		cfi_udelay(1);
+		UDELAY(map, chip, adr, 1);
 		spin_lock(chip->mutex);
 	}
 	
 	/* Done and happy. */
 	chip->state = FL_STATUS;
+	xip_enable(map, chip, adr);
 	put_chip(map, chip, adr);
 	spin_unlock(chip->mutex);
 	return 0;
@@ -1875,7 +2136,7 @@ static void cfi_intelext_destroy(struct mtd_info *mtd)
 static char im_name_1[]="cfi_cmdset_0001";
 static char im_name_3[]="cfi_cmdset_0003";
 
-int __init cfi_intelext_init(void)
+static int __init cfi_intelext_init(void)
 {
 	inter_module_register(im_name_1, THIS_MODULE, &cfi_cmdset_0001);
 	inter_module_register(im_name_3, THIS_MODULE, &cfi_cmdset_0001);

drivers/mtd/chips/cfi_probe.c

 /* 
    Common Flash Interface probe code.
    (C) 2000 Red Hat. GPL'd.
-   $Id: cfi_probe.c,v 1.79 2004/10/20 23:04:01 dwmw2 Exp $
+   $Id: cfi_probe.c,v 1.83 2004/11/16 18:19:02 nico Exp $
 */
 
 #include <linux/config.h>
@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 #include <linux/interrupt.h>
 
+#include <linux/mtd/xip.h>
 #include <linux/mtd/map.h>
 #include <linux/mtd/cfi.h>
 #include <linux/mtd/gen_probe.h>
@@ -31,11 +32,47 @@ static int cfi_chip_setup(struct map_info *map, struct cfi_private *cfi);
 
 struct mtd_info *cfi_probe(struct map_info *map);
 
+#ifdef CONFIG_MTD_XIP
+
+/* only needed for short periods, so this is rather simple */
+#define xip_disable()	local_irq_disable()
+
+#define xip_allowed(base, map) \
+do { \
+	(void) map_read(map, base); \
+	asm volatile (".rep 8; nop; .endr"); \
+	local_irq_enable(); \
+} while (0)
+
+#define xip_enable(base, map, cfi) \
+do { \
+	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL); \
+	cfi_send_gen_cmd(0xFF, 0, base, map, cfi, cfi->device_type, NULL); \
+	xip_allowed(base, map); \
+} while (0)
+
+#define xip_disable_qry(base, map, cfi) \
+do { \
+	xip_disable(); \
+	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL); \
+	cfi_send_gen_cmd(0xFF, 0, base, map, cfi, cfi->device_type, NULL); \
+	cfi_send_gen_cmd(0x98, 0x55, base, map, cfi, cfi->device_type, NULL); \
+} while (0)
+
+#else
+
+#define xip_disable()			do { } while (0)
+#define xip_allowed(base, map)		do { } while (0)
+#define xip_enable(base, map, cfi)	do { } while (0)
+#define xip_disable_qry(base, map, cfi) do { } while (0)
+
+#endif
+
 /* check for QRY.
    in: interleave,type,mode
    ret: table index, <0 for error
  */
-static int qry_present(struct map_info *map, __u32 base,
+static int __xipram qry_present(struct map_info *map, __u32 base,
 				struct cfi_private *cfi)
 {
 	int osf = cfi->interleave * cfi->device_type;	// scale factor
@@ -59,10 +96,10 @@ static int qry_present(struct map_info *map, __u32 base,
 	if (!map_word_equal(map, qry[2], val[2]))
 		return 0;
 
-	return 1; 	// nothing found
+	return 1; 	// "QRY" found
 }
 
-static int cfi_probe_chip(struct map_info *map, __u32 base,
+static int __xipram cfi_probe_chip(struct map_info *map, __u32 base,
 				   unsigned long *chip_map, struct cfi_private *cfi)
 {
 	int i;
@@ -79,12 +116,16 @@ static int cfi_probe_chip(struct map_info *map, __u32 base,
 			(unsigned long)base + 0x55, map->size -1);
 		return 0;
 	}
+
+	xip_disable();
 	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
 	cfi_send_gen_cmd(0xFF, 0, base, map, cfi, cfi->device_type, NULL);
 	cfi_send_gen_cmd(0x98, 0x55, base, map, cfi, cfi->device_type, NULL);
 
-	if (!qry_present(map,base,cfi))
+	if (!qry_present(map,base,cfi)) {
+		xip_enable(base, map, cfi);
 		return 0;
+	}
 
 	if (!cfi->numchips) {
 		/* This is the first time we're called. Set up the CFI 
@@ -110,6 +151,7 @@ static int cfi_probe_chip(struct map_info *map, __u32 base,
 
 			/* If the QRY marker goes away, it's an alias */
 			if (!qry_present(map, start, cfi)) {
+				xip_allowed(base, map);
 				printk(KERN_DEBUG "%s: Found an alias at 0x%x for the chip at 0x%lx\n",
 				       map->name, base, start);
 				return 0;
@@ -122,6 +164,7 @@ static int cfi_probe_chip(struct map_info *map, __u32 base,
 			cfi_send_gen_cmd(0xFF, 0, start, map, cfi, cfi->device_type, NULL);
 			
 			if (qry_present(map, base, cfi)) {
+				xip_allowed(base, map);
 				printk(KERN_DEBUG "%s: Found an alias at 0x%x for the chip at 0x%lx\n",
 				       map->name, base, start);
 				return 0;
@@ -137,6 +180,7 @@ static int cfi_probe_chip(struct map_info *map, __u32 base,
 	/* Put it back into Read Mode */
 	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
 	cfi_send_gen_cmd(0xFF, 0, base, map, cfi, cfi->device_type, NULL);
+	xip_allowed(base, map);
 
 	printk(KERN_INFO "%s: Found %d x%d devices at 0x%x in %d-bit bank\n",
 	       map->name, cfi->interleave, cfi->device_type*8, base,
@@ -145,7 +189,7 @@ static int cfi_probe_chip(struct map_info *map, __u32 base,
 	return 1;
 }
 
-static int cfi_chip_setup(struct map_info *map, 
+static int __xipram cfi_chip_setup(struct map_info *map, 
 				   struct cfi_private *cfi)
 {
 	int ofs_factor = cfi->interleave*cfi->device_type;
@@ -153,6 +197,7 @@ static int cfi_chip_setup(struct map_info *map,
 	int num_erase_regions = cfi_read_query(map, base + (0x10 + 28)*ofs_factor);
 	int i;
 
+	xip_enable(base, map, cfi);
 #ifdef DEBUG_CFI
 	printk("Number of erase regions: %d\n", num_erase_regions);
 #endif
@@ -170,9 +215,29 @@ static int cfi_chip_setup(struct map_info *map,
 	cfi->cfi_mode = CFI_MODE_CFI;
 	
 	/* Read the CFI info structure */
-	for (i=0; i<(sizeof(struct cfi_ident) + num_erase_regions * 4); i++) {
+	xip_disable_qry(base, map, cfi);
+	for (i=0; i<(sizeof(struct cfi_ident) + num_erase_regions * 4); i++)
 		((unsigned char *)cfi->cfiq)[i] = cfi_read_query(map,base + (0x10 + i)*ofs_factor);
-	}
+
+	/* Note we put the device back into Read Mode BEFORE going into Auto
+	 * Select Mode, as some devices support nesting of modes, others
+	 * don't. This way should always work.
+	 * On cmdset 0001 the writes of 0xaa and 0x55 are not needed, and
+	 * so should be treated as nops or illegal (and so put the device
+	 * back into Read Mode, which is a nop in this case).
+	 */
+	cfi_send_gen_cmd(0xf0,     0, base, map, cfi, cfi->device_type, NULL);
+	cfi_send_gen_cmd(0xaa, 0x555, base, map, cfi, cfi->device_type, NULL);
+	cfi_send_gen_cmd(0x55, 0x2aa, base, map, cfi, cfi->device_type, NULL);
+	cfi_send_gen_cmd(0x90, 0x555, base, map, cfi, cfi->device_type, NULL);
+	cfi->mfr = cfi_read_query(map, base);
+	cfi->id = cfi_read_query(map, base + ofs_factor);    
+
+	/* Put it back into Read Mode */
+	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
+	/* ... even if it's an Intel chip */
+	cfi_send_gen_cmd(0xFF, 0, base, map, cfi, cfi->device_type, NULL);
+	xip_allowed(base, map);
 
 	/* Do any necessary byteswapping */
 	cfi->cfiq->P_ID = le16_to_cpu(cfi->cfiq->P_ID);
@@ -198,25 +263,6 @@ static int cfi_chip_setup(struct map_info *map,
 #endif
 	}
 
-	/* Note we put the device back into Read Mode BEFORE going into Auto
-	 * Select Mode, as some devices support nesting of modes, others
-	 * don't. This way should always work.
-	 * On cmdset 0001 the writes of 0xaa and 0x55 are not needed, and
-	 * so should be treated as nops or illegal (and so put the device
-	 * back into Read Mode, which is a nop in this case).
-	 */
-	cfi_send_gen_cmd(0xf0,     0, base, map, cfi, cfi->device_type, NULL);
-	cfi_send_gen_cmd(0xaa, 0x555, base, map, cfi, cfi->device_type, NULL);
-	cfi_send_gen_cmd(0x55, 0x2aa, base, map, cfi, cfi->device_type, NULL);
-	cfi_send_gen_cmd(0x90, 0x555, base, map, cfi, cfi->device_type, NULL);
-	cfi->mfr = cfi_read_query(map, base);
-	cfi->id = cfi_read_query(map, base + ofs_factor);    
-
-	/* Put it back into Read Mode */
-	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
-	/* ... even if it's an Intel chip */
-	cfi_send_gen_cmd(0xFF, 0, base, map, cfi, cfi->device_type, NULL);
-
 	printk(KERN_INFO "%s: Found %d x%d devices at 0x%x in %d-bit bank\n",
 	       map->name, cfi->interleave, cfi->device_type*8, base,
 	       map->bankwidth*8);

drivers/mtd/chips/cfi_util.c

@@ -7,7 +7,7 @@
  *
  * This code is covered by the GPL.
  *
- * $Id: cfi_util.c,v 1.5 2004/08/12 06:40:23 eric Exp $
+ * $Id: cfi_util.c,v 1.7 2004/11/05 22:41:05 nico Exp $
  *
  */
 
@@ -22,13 +22,14 @@
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
+#include <linux/mtd/xip.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/map.h>
 #include <linux/mtd/cfi.h>
 #include <linux/mtd/compatmac.h>
 
 struct cfi_extquery *
-cfi_read_pri(struct map_info *map, __u16 adr, __u16 size, const char* name)
+__xipram cfi_read_pri(struct map_info *map, __u16 adr, __u16 size, const char* name)
 {
 	struct cfi_private *cfi = map->fldrv_priv;
 	__u32 base = 0; // cfi->chips[0].start;
@@ -40,21 +41,35 @@ cfi_read_pri(struct map_info *map, __u16 adr, __u16 size, const char* name)
 	if (!adr)
 		goto out;
 
-	/* Switch it into Query Mode */
-	cfi_send_gen_cmd(0x98, 0x55, base, map, cfi, cfi->device_type, NULL);
-
 	extp = kmalloc(size, GFP_KERNEL);
 	if (!extp) {
 		printk(KERN_ERR "Failed to allocate memory\n");
 		goto out;
 	}
 
+#ifdef CONFIG_MTD_XIP
+	local_irq_disable();
+#endif
+
+	/* Switch it into Query Mode */
+	cfi_send_gen_cmd(0x98, 0x55, base, map, cfi, cfi->device_type, NULL);
+
 	/* Read in the Extended Query Table */
 	for (i=0; i<size; i++) {
 		((unsigned char *)extp)[i] = 
 			cfi_read_query(map, base+((adr+i)*ofs_factor));
 	}
 
+	/* Make sure it returns to read mode */
+	cfi_send_gen_cmd(0xf0, 0, base, map, cfi, cfi->device_type, NULL);
+	cfi_send_gen_cmd(0xff, 0, base, map, cfi, cfi->device_type, NULL);
+
+#ifdef CONFIG_MTD_XIP
+	(void) map_read(map, base);
+	asm volatile (".rep 8; nop; .endr");
+	local_irq_enable();
+#endif
+
 	if (extp->MajorVersion != '1' || 
 	    (extp->MinorVersion < '0' || extp->MinorVersion > '3')) {
 		printk(KERN_WARNING "  Unknown %s Extended Query "
@@ -62,15 +77,9 @@ cfi_read_pri(struct map_info *map, __u16 adr, __u16 size, const char* name)
 		       extp->MinorVersion);
 		kfree(extp);
 		extp = NULL;
-		goto out;
 	}
 
-out:
-	/* Make sure it's in read mode */
-	cfi_send_gen_cmd(0xf0, 0, base, map, cfi, cfi->device_type, NULL);
-	cfi_send_gen_cmd(0xff, 0, base, map, cfi, cfi->device_type, NULL);
-
-	return extp;
+ out:	return extp;
 }
 
 EXPORT_SYMBOL(cfi_read_pri);

include/linux/mtd/flashchip.h

@@ -6,7 +6,7 @@
  *
  * (C) 2000 Red Hat. GPLd.
  *
- * $Id: flashchip.h,v 1.14 2004/06/15 16:44:59 nico Exp $
+ * $Id: flashchip.h,v 1.15 2004/11/05 22:41:06 nico Exp $
  *
  */
 
@@ -37,6 +37,8 @@ typedef enum {
 	FL_LOCKING,
 	FL_UNLOCKING,
 	FL_POINT,
+	FL_XIP_WHILE_ERASING,
+	FL_XIP_WHILE_WRITING,
 	FL_UNKNOWN
 } flstate_t;
 

include/linux/mtd/xip.h

+/*
+ * MTD primitives for XIP support
+ *
+ * Author:	Nicolas Pitre
+ * Created:	Nov 2, 2004
+ * Copyright:	(C) 2004 MontaVista Software, Inc.
+ *
+ * This XIP support for MTD has been loosely inspired
+ * by an earlier patch authored by David Woodhouse.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * $Id: xip.h,v 1.1 2004/11/05 22:41:06 nico Exp $
+ */
+
+#ifndef __LINUX_MTD_XIP_H__
+#define __LINUX_MTD_XIP_H__
+
+#include <linux/config.h>
+
+#ifdef CONFIG_MTD_XIP
+
+/*
+ * Function that are modifying the flash state away from array mode must
+ * obviously not be running from flash.  The __xipram is therefore marking
+ * those functions so they get relocated to ram.
+ */
+#define __xipram __attribute__ ((__section__ (".data")))
+
+/*
+ * We really don't want gcc to guess anything.
+ * We absolutely _need_ proper inlining.
+ */
+#include <linux/compiler.h>
+
+/*
+ * Each architecture has to provide the following macros.  They must access
+ * the hardware directly and not rely on any other (XIP) functions since they
+ * won't be available when used (flash not in array mode).
+ *
+ * xip_irqpending()
+ *
+ * 	return non zero when any hardware interrupt is pending.
+ *
+ * xip_currtime()
+ *
+ * 	return a platform specific time reference to be used with
+ * 	xip_elapsed_since().
+ *
+ * xip_elapsed_since(x)
+ *
+ * 	return in usecs the elapsed timebetween now and the reference x as
+ * 	returned by xip_currtime().
+ *
+ * 	note 1: convertion to usec can be approximated, as long as the
+ * 		returned value is <= the real elapsed time.
+ * 	note 2: this should be able to cope with a few seconds without
+ * 		overflowing.
+ */
+
+#if defined(CONFIG_ARCH_SA1100) || defined(CONFIG_ARCH_PXA)
+
+#include <asm/hardware.h>
+#ifdef CONFIG_ARCH_PXA
+#include <asm/arch/pxa-regs.h>
+#endif
+
+#define xip_irqpending()	(ICIP & ICMR)
+
+/* we sample OSCR and convert desired delta to usec (1/4 ~= 1000000/3686400) */
+#define xip_currtime()		(OSCR)
+#define xip_elapsed_since(x)	(signed)((OSCR - (x)) / 4)
+
+#else
+#error "missing IRQ and timer primitives for XIP MTD support"
+#endif
+
+/*
+ * xip_cpu_idle() is used when waiting for a delay equal or larger than
+ * the system timer tick period.  This should put the CPU into idle mode
+ * to save power and to be woken up only when some interrupts are pending.
+ * As above, this should not rely upon standard kernel code.
+ */
+
+#if defined(CONFIG_CPU_XSCALE)
+#define xip_cpu_idle()  asm volatile ("mcr p14, 0, %0, c7, c0, 0" :: "r" (1))
+#else
+#define xip_cpu_idle()  do { } while (0)
+#endif
+
+#else
+
+#define __xipram
+
+#endif /* CONFIG_MTD_XIP */
+
+#endif /* __LINUX_MTD_XIP_H__ */