Commit d49f5790 authored by Masahiro Yamada's avatar Masahiro Yamada Committed by Boris Brezillon
Browse files

mtd: nand: denali: use interrupt instead of polling for bank reset 



The current bank reset implementation polls the INTR_STATUS register
until interested bits are set.  This is not good because:

- polling simply wastes time-slice of the thread

- The while() loop may continue eternally if no bit is set, for
  example, due to the controller problem.  The denali_wait_for_irq()
  uses wait_for_completion_timeout(), which is safer.

We can use interrupt by moving the denali_reset_bank() call below
the interrupt setup.

Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
parent f486287d

drivers/mtd/nand/denali.c

+14 −14
Original line number Diff line number Diff line
@@ -1028,24 +1028,25 @@ static int denali_setup_data_interface(struct mtd_info *mtd, int chipnr, 


static void denali_reset_banks(struct denali_nand_info *denali)

{

	u32 irq_status;

	int i;



	denali_clear_irq_all(denali);



	for (i = 0; i < denali->max_banks; i++) {

		iowrite32(1 << i, denali->flash_reg + DEVICE_RESET);

		while (!(ioread32(denali->flash_reg + INTR_STATUS(i)) &

			(INTR__RST_COMP | INTR__TIME_OUT)))

			cpu_relax();

		if (!(ioread32(denali->flash_reg + INTR_STATUS(i)) &

		      INTR__INT_ACT))

		denali->flash_bank = i;



		denali_reset_irq(denali);



		iowrite32(DEVICE_RESET__BANK(i),

			  denali->flash_reg + DEVICE_RESET);



		irq_status = denali_wait_for_irq(denali,

			INTR__RST_COMP | INTR__INT_ACT | INTR__TIME_OUT);

		if (!(irq_status & INTR__INT_ACT))

			break;

	}



	dev_dbg(denali->dev, "%d chips connected\n", i);

	denali->max_banks = i;



	denali_clear_irq_all(denali);

}



static void denali_hw_init(struct denali_nand_info *denali)
@@ -1067,7 +1068,6 @@ static void denali_hw_init(struct denali_nand_info *denali) 
	denali->bbtskipbytes = ioread32(denali->flash_reg +

						SPARE_AREA_SKIP_BYTES);

	detect_max_banks(denali);

	denali_reset_banks(denali);

	iowrite32(0x0F, denali->flash_reg + RB_PIN_ENABLED);

	iowrite32(CHIP_EN_DONT_CARE__FLAG,

			denali->flash_reg + CHIP_ENABLE_DONT_CARE);
@@ -1185,9 +1185,6 @@ static void denali_drv_init(struct denali_nand_info *denali) 
	 * element that might be access shared data (interrupt status)

	 */

	spin_lock_init(&denali->irq_lock);



	/* indicate that MTD has not selected a valid bank yet */

	denali->flash_bank = CHIP_SELECT_INVALID;

}



static int denali_multidev_fixup(struct denali_nand_info *denali)
@@ -1262,6 +1259,9 @@ int denali_init(struct denali_nand_info *denali) 
	}



	denali_enable_irq(denali);

	denali_reset_banks(denali);



	denali->flash_bank = CHIP_SELECT_INVALID;



	nand_set_flash_node(chip, denali->dev->of_node);

	/* Fallback to the default name if DT did not give "label" property */

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