Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751455AbdFEX1u (ORCPT ); Mon, 5 Jun 2017 19:27:50 -0400 Received: from conuserg-10.nifty.com ([210.131.2.77]:32212 "EHLO conuserg-10.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751313AbdFEXZT (ORCPT ); Mon, 5 Jun 2017 19:25:19 -0400 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-10.nifty.com v55NMD5j004412 X-Nifty-SrcIP: [118.110.19.204] From: Masahiro Yamada To: linux-mtd@lists.infradead.org Cc: Enrico Jorns , Artem Bityutskiy , Dinh Nguyen , Boris Brezillon , Marek Vasut , Graham Moore , David Woodhouse , Masami Hiramatsu , Chuanxiao Dong , Jassi Brar , Masahiro Yamada , Cyrille Pitchen , linux-kernel@vger.kernel.org, Brian Norris , Richard Weinberger Subject: [PATCH v4 09/23] mtd: nand: denali: remove unneeded find_valid_banks() Date: Tue, 6 Jun 2017 08:21:48 +0900 Message-Id: <1496704922-12261-10-git-send-email-yamada.masahiro@socionext.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1496704922-12261-1-git-send-email-yamada.masahiro@socionext.com> References: <1496704922-12261-1-git-send-email-yamada.masahiro@socionext.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3134 Lines: 103 The function find_valid_banks() issues the Read ID (0x90) command, then compares the first byte (Manufacturer ID) of each bank with the one of bank0. This is equivalent to what nand_scan_ident() does. The number of chips is detected there, so this is unneeded. What is worse for find_valid_banks() is that, if multiple chips are connected to INTEL_CE4100 platform, it crashes the kernel by BUG(). This is what we should avoid. This function is just harmful and unneeded. Signed-off-by: Masahiro Yamada --- Changes in v4: None Changes in v3: None Changes in v2: - Newly added drivers/mtd/nand/denali.c | 47 ----------------------------------------------- drivers/mtd/nand/denali.h | 1 - 2 files changed, 48 deletions(-) diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c index 4017262..a289011 100644 --- a/drivers/mtd/nand/denali.c +++ b/drivers/mtd/nand/denali.c @@ -338,51 +338,6 @@ static void get_samsung_nand_para(struct denali_nand_info *denali, } /* - * determines how many NAND chips are connected to the controller. Note for - * Intel CE4100 devices we don't support more than one device. - */ -static void find_valid_banks(struct denali_nand_info *denali) -{ - uint32_t id[denali->max_banks]; - int i; - - denali->total_used_banks = 1; - for (i = 0; i < denali->max_banks; i++) { - index_addr(denali, MODE_11 | (i << 24) | 0, 0x90); - index_addr(denali, MODE_11 | (i << 24) | 1, 0); - index_addr_read_data(denali, MODE_11 | (i << 24) | 2, &id[i]); - - dev_dbg(denali->dev, - "Return 1st ID for bank[%d]: %x\n", i, id[i]); - - if (i == 0) { - if (!(id[i] & 0x0ff)) - break; /* WTF? */ - } else { - if ((id[i] & 0x0ff) == (id[0] & 0x0ff)) - denali->total_used_banks++; - else - break; - } - } - - if (denali->platform == INTEL_CE4100) { - /* - * Platform limitations of the CE4100 device limit - * users to a single chip solution for NAND. - * Multichip support is not enabled. - */ - if (denali->total_used_banks != 1) { - dev_err(denali->dev, - "Sorry, Intel CE4100 only supports a single NAND device.\n"); - BUG(); - } - } - dev_dbg(denali->dev, - "denali->total_used_banks: %d\n", denali->total_used_banks); -} - -/* * Use the configuration feature register to determine the maximum number of * banks that the hardware supports. */ @@ -439,8 +394,6 @@ static uint16_t denali_nand_timing_set(struct denali_nand_info *denali) ioread32(denali->flash_reg + RDWR_EN_HI_CNT), ioread32(denali->flash_reg + CS_SETUP_CNT)); - find_valid_banks(denali); - /* * If the user specified to override the default timings * with a specific ONFI mode, we apply those changes here. diff --git a/drivers/mtd/nand/denali.h b/drivers/mtd/nand/denali.h index 0e9297d..80767cf 100644 --- a/drivers/mtd/nand/denali.h +++ b/drivers/mtd/nand/denali.h @@ -326,7 +326,6 @@ struct denali_nand_info { int platform; struct nand_buf buf; struct device *dev; - int total_used_banks; int page; void __iomem *flash_reg; /* Register Interface */ void __iomem *flash_mem; /* Host Data/Command Interface */ -- 2.7.4