+#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.
+ */
+
+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 */
+ 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);
+ xip_iprefetch();
+ local_irq_enable();
+}
+
+/*
+ * When a delay is required for the flash operation to complete, the
+ * xip_wait_for_operation() 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 int __xipram xip_wait_for_operation(
+ struct map_info *map, struct flchip *chip,
+ unsigned long adr, unsigned int chip_op_time )
+{
+ struct cfi_private *cfi = map->fldrv_priv;
+ struct cfi_pri_intelext *cfip = cfi->cmdset_priv;
+ map_word status, OK = CMD(0x80);
+ unsigned long usec, suspended, start, done;
+ flstate_t oldstate, newstate;
+
+ start = xip_currtime();
+ usec = chip_op_time * 8;
+ if (usec == 0)
+ usec = 500000;
+ done = 0;
+
+ 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!
+ */
+ usec -= done;
+ map_write(map, CMD(0xb0), adr);
+ map_write(map, CMD(0x70), adr);
+ 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 -EIO;
+ }
+ 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();
+ spin_unlock(chip->mutex);
+ 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.
+ */
+ spin_lock(chip->mutex);
+ while (chip->state != newstate) {
+ DECLARE_WAITQUEUE(wait, current);
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ add_wait_queue(&chip->wq, &wait);
+ spin_unlock(chip->mutex);
+ schedule();
+ remove_wait_queue(&chip->wq, &wait);
+ spin_lock(chip->mutex);
+ }
+ /* 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);
+ done = xip_elapsed_since(start);
+ } while (!map_word_andequal(map, status, OK, OK)
+ && done < usec);
+
+ return (done >= usec) ? -ETIME : 0;
+}
+
+/*
+ * 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
+ * and stub it out from INVAL_CACHE_AND_WAIT.
+ */
+#define XIP_INVAL_CACHED_RANGE(map, from, size) \
+ INVALIDATE_CACHED_RANGE(map, from, size)
+
+#define INVAL_CACHE_AND_WAIT(map, chip, cmd_adr, inval_adr, inval_len, usec) \
+ xip_wait_for_operation(map, chip, cmd_adr, usec)
+
+#else
+
+#define xip_disable(map, chip, adr)
+#define xip_enable(map, chip, adr)
+#define XIP_INVAL_CACHED_RANGE(x...)
+#define INVAL_CACHE_AND_WAIT inval_cache_and_wait_for_operation
+
+static int inval_cache_and_wait_for_operation(
+ struct map_info *map, struct flchip *chip,
+ unsigned long cmd_adr, unsigned long inval_adr, int inval_len,
+ unsigned int chip_op_time)
+{
+ struct cfi_private *cfi = map->fldrv_priv;
+ map_word status, status_OK = CMD(0x80);
+ int chip_state = chip->state;
+ unsigned int timeo, sleep_time;
+
+ spin_unlock(chip->mutex);
+ if (inval_len)
+ INVALIDATE_CACHED_RANGE(map, inval_adr, inval_len);
+ spin_lock(chip->mutex);
+
+ /* set our timeout to 8 times the expected delay */
+ timeo = chip_op_time * 8;
+ if (!timeo)
+ timeo = 500000;
+ sleep_time = chip_op_time / 2;
+
+ for (;;) {
+ status = map_read(map, cmd_adr);
+ if (map_word_andequal(map, status, status_OK, status_OK))
+ break;
+
+ if (!timeo) {
+ map_write(map, CMD(0x70), cmd_adr);
+ chip->state = FL_STATUS;
+ return -ETIME;
+ }
+
+ /* OK Still waiting. Drop the lock, wait a while and retry. */
+ spin_unlock(chip->mutex);
+ if (sleep_time >= 1000000/HZ) {
+ /*
+ * Half of the normal delay still remaining
+ * can be performed with a sleeping delay instead
+ * of busy waiting.
+ */
+ msleep(sleep_time/1000);
+ timeo -= sleep_time;
+ sleep_time = 1000000/HZ;
+ } else {
+ udelay(1);
+ cond_resched();
+ timeo--;
+ }
+ spin_lock(chip->mutex);
+
+ while (chip->state != chip_state) {
+ /* Someone's suspended the operation: sleep */
+ DECLARE_WAITQUEUE(wait, current);
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ add_wait_queue(&chip->wq, &wait);
+ spin_unlock(chip->mutex);
+ schedule();
+ remove_wait_queue(&chip->wq, &wait);
+ spin_lock(chip->mutex);
+ }
+ }
+
+ /* Done and happy. */
+ chip->state = FL_STATUS;
+ return 0;
+}
+
+#endif
+
+#define WAIT_TIMEOUT(map, chip, adr, udelay) \
+ INVAL_CACHE_AND_WAIT(map, chip, adr, 0, 0, udelay);
+
+