From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753572AbdFMNsj (ORCPT ); Tue, 13 Jun 2017 09:48:39 -0400 Received: from conuserg-09.nifty.com ([210.131.2.76]:31110 "EHLO conuserg-09.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753553AbdFMNsh (ORCPT ); Tue, 13 Jun 2017 09:48:37 -0400 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-09.nifty.com v5DDjxiq031338 X-Nifty-SrcIP: [153.142.97.92] From: Masahiro Yamada To: linux-mtd@lists.infradead.org Cc: Enrico Jorns , Artem Bityutskiy , Dinh Nguyen , Boris Brezillon , Marek Vasut , David Woodhouse , Masami Hiramatsu , Chuanxiao Dong , Jassi Brar , Masahiro Yamada , Cyrille Pitchen , linux-kernel@vger.kernel.org, Brian Norris , Richard Weinberger Subject: [PATCH v7 07/16] mtd: nand: denali: use interrupt instead of polling for bank reset Date: Tue, 13 Jun 2017 22:45:41 +0900 Message-Id: <1497361550-8115-8-git-send-email-yamada.masahiro@socionext.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1497361550-8115-1-git-send-email-yamada.masahiro@socionext.com> References: <1497361550-8115-1-git-send-email-yamada.masahiro@socionext.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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: Masahiro Yamada --- Changes in v7: None Changes in v6: None Changes in v5: None Changes in v4: None Changes in v3: None Changes in v2: - Newly added drivers/mtd/nand/denali.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c index 3169ba58c58a..31d987d26e12 100644 --- a/drivers/mtd/nand/denali.c +++ b/drivers/mtd/nand/denali.c @@ -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 */ -- 2.7.4