mmc: sdhci-esdhc-imx: fix lockdep splat upon tuning

=================================
[ INFO: inconsistent lock state ]
3.14.0-rc1+ #490 Not tainted
---------------------------------
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
kworker/u8:0/6 [HC0[0]:SC0[0]:HE1:SE1] takes:
 (&(&host->lock)->rlock#2){?.-...}, at: [<c04b57a4>] esdhc_send_tuning_cmd+0x104/0x14c
{IN-HARDIRQ-W} state was registered at:
  [<c00652fc>] mark_lock+0x15c/0x6f8
  [<c0066354>] __lock_acquire+0xabc/0x1ca0
  [<c0067ad8>] lock_acquire+0xa0/0x130
  [<c0697a44>] _raw_spin_lock+0x34/0x44
  [<c04b0dbc>] sdhci_irq+0x20/0xa40
  [<c0071b1c>] handle_irq_event_percpu+0x74/0x284
  [<c0071d70>] handle_irq_event+0x44/0x64
  [<c0074db8>] handle_fasteoi_irq+0xac/0x140
  [<c007147c>] generic_handle_irq+0x28/0x38
  [<c000efd4>] handle_IRQ+0x40/0x98
  [<c0008584>] gic_handle_irq+0x30/0x64
  [<c0013144>] __irq_svc+0x44/0x58
  [<c0028fc8>] irq_exit+0xc0/0x120
  [<c000efd8>] handle_IRQ+0x44/0x98
  [<c0008584>] gic_handle_irq+0x30/0x64
  [<c0013144>] __irq_svc+0x44/0x58
  [<c068f398>] printk+0x3c/0x44
  [<c03191d0>] _regulator_get+0x1b4/0x1e0
  [<c031924c>] regulator_get+0x18/0x1c
  [<c049fbc4>] mmc_add_host+0x30/0x1c0
  [<c04b2e10>] sdhci_add_host+0x804/0xbbc
  [<c04b5318>] sdhci_esdhc_imx_probe+0x380/0x674
  [<c036d530>] platform_drv_probe+0x20/0x50
  [<c036b948>] driver_probe_device+0x120/0x234
  [<c036baf8>] __driver_attach+0x9c/0xa0
  [<c036a04c>] bus_for_each_dev+0x5c/0x90
  [<c036b418>] driver_attach+0x24/0x28
  [<c036b018>] bus_add_driver+0xe4/0x1d8
  [<c036c1b0>] driver_register+0x80/0xfc
  [<c036ce28>] __platform_driver_register+0x50/0x64
  [<c093706c>] sdhci_esdhc_imx_driver_init+0x18/0x20
  [<c0008834>] do_one_initcall+0x3c/0x164
  [<c0901c94>] kernel_init_freeable+0x104/0x1d0
  [<c068c45c>] kernel_init+0x10/0x118
  [<c000e768>] ret_from_fork+0x14/0x2c
irq event stamp: 5933
hardirqs last  enabled at (5933): [<c069813c>] _raw_spin_unlock_irqrestore+0x38/0x4c
hardirqs last disabled at (5932): [<c0697b04>] _raw_spin_lock_irqsave+0x24/0x60
softirqs last  enabled at (5914): [<c0028ba0>] __do_softirq+0x260/0x360
softirqs last disabled at (5909): [<c0028fc8>] irq_exit+0xc0/0x120

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&host->lock)->rlock#2);
  <Interrupt>
    lock(&(&host->lock)->rlock#2);

 *** DEADLOCK ***

2 locks held by kworker/u8:0/6:
 #0:  (kmmcd){.+.+.+}, at: [<c003d890>] process_one_work+0x134/0x4e8
 #1:  ((&(&host->detect)->work)){+.+.+.}, at: [<c003d890>] process_one_work+0x134/0x4e8

stack backtrace:
CPU: 2 PID: 6 Comm: kworker/u8:0 Not tainted 3.14.0-rc1+ #490
Workqueue: kmmcd mmc_rescan
Backtrace:
[<c00124a0>] (dump_backtrace) from [<c0012640>] (show_stack+0x18/0x1c)
[<c0012628>] (show_stack) from [<c069164c>] (dump_stack+0x70/0x8c)
[<c06915dc>] (dump_stack) from [<c068f080>] (print_usage_bug+0x274/0x2e4)
[<c068ee0c>] (print_usage_bug) from [<c0065774>] (mark_lock+0x5d4/0x6f8)
[<c00651a0>] (mark_lock) from [<c0065e6c>] (__lock_acquire+0x5d4/0x1ca0)
[<c0065898>] (__lock_acquire) from [<c0067ad8>] (lock_acquire+0xa0/0x130)
[<c0067a38>] (lock_acquire) from [<c0697a44>] (_raw_spin_lock+0x34/0x44)
[<c0697a10>] (_raw_spin_lock) from [<c04b57a4>] (esdhc_send_tuning_cmd+0x104/0x14c)
[<c04b56a0>] (esdhc_send_tuning_cmd) from [<c04b582c>] (esdhc_executing_tuning+0x40/0x100)
[<c04b57ec>] (esdhc_executing_tuning) from [<c04afa54>] (sdhci_execute_tuning+0xcc/0x754)
[<c04af988>] (sdhci_execute_tuning) from [<c04a4684>] (mmc_sd_init_card+0x65c/0x694)
[<c04a4028>] (mmc_sd_init_card) from [<c04a48f0>] (mmc_attach_sd+0xb0/0x184)
[<c04a4840>] (mmc_attach_sd) from [<c049eb28>] (mmc_rescan+0x26c/0x2e8)
[<c049e8bc>] (mmc_rescan) from [<c003d914>] (process_one_work+0x1b8/0x4e8)
[<c003d75c>] (process_one_work) from [<c003e090>] (worker_thread+0x13c/0x3f8)
[<c003df54>] (worker_thread) from [<c00449bc>] (kthread+0xcc/0xe8)
[<c00448f0>] (kthread) from [<c000e768>] (ret_from_fork+0x14/0x2c)

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Markus Pargmann <mpa@pengutronix.de>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>

drivers/mmc/host/sdhci-esdhc-imx.c

@@ -738,14 +738,12 @@ static int esdhc_send_tuning_cmd(struct sdhci_host *host, u32 opcode,
 	mrq.done = esdhc_request_done;
 	init_completion(&(mrq.completion));
 
-	disable_irq(host->irq);
-	spin_lock(&host->lock);
+	spin_lock_irq(&host->lock);
 	host->mrq = &mrq;
 
 	sdhci_send_command(host, mrq.cmd);
 
-	spin_unlock(&host->lock);
-	enable_irq(host->irq);
+	spin_unlock_irq(&host->lock);
 
 	wait_for_completion(&mrq.completion);