linux-kernel - [PATCH 31/39] mtd: nand: denali: remove meaningless writes to read-only registers

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Message-Id: <1480183585-592-32-git-send-email-yamada.masahiro@socionext.com>
Date:   Sun, 27 Nov 2016 03:06:17 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     linux-mtd@...ts.infradead.org
Cc:     Masahiro Yamada <yamada.masahiro@...ionext.com>,
        linux-kernel@...r.kernel.org,
        Boris Brezillon <boris.brezillon@...e-electrons.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Brian Norris <computersforpeace@...il.com>,
        Richard Weinberger <richard@....at>,
        David Woodhouse <dwmw2@...radead.org>,
        Cyrille Pitchen <cyrille.pitchen@...el.com>
Subject: [PATCH 31/39] mtd: nand: denali: remove meaningless writes to read-only registers

The write accesses to LOGICAL_PAGE_{DATA,SPARE}_SIZE have no effect
because the Denali User's Guide says these registers are read-only.

The hardware automatically multiplies the main/spare size by the
number of devices and update LOGICAL_PAGE_{DATA,SPARE}_SIZE.

Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
---

 drivers/mtd/nand/denali.c | 16 ----------------
 1 file changed, 16 deletions(-)

diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c
index 4b2bbcb..9193331 100644
--- a/drivers/mtd/nand/denali.c
+++ b/drivers/mtd/nand/denali.c
@@ -342,8 +342,6 @@ static void get_samsung_nand_para(struct denali_nand_info *denali, u8 device_id)
 
 static void get_toshiba_nand_para(struct denali_nand_info *denali)
 {
-	u32 tmp;
-
 	/*
 	 * Workaround to fix a controller bug which reports a wrong
 	 * spare area size for some kind of Toshiba NAND device
@@ -351,10 +349,6 @@ static void get_toshiba_nand_para(struct denali_nand_info *denali)
 	if ((ioread32(denali->flash_reg + DEVICE_MAIN_AREA_SIZE) == 4096) &&
 		(ioread32(denali->flash_reg + DEVICE_SPARE_AREA_SIZE) == 64)) {
 		iowrite32(216, denali->flash_reg + DEVICE_SPARE_AREA_SIZE);
-		tmp = ioread32(denali->flash_reg + DEVICES_CONNECTED) *
-			ioread32(denali->flash_reg + DEVICE_SPARE_AREA_SIZE);
-		iowrite32(tmp,
-				denali->flash_reg + LOGICAL_PAGE_SPARE_SIZE);
 #if SUPPORT_15BITECC
 		iowrite32(15, denali->flash_reg + ECC_CORRECTION);
 #elif SUPPORT_8BITECC
@@ -365,22 +359,12 @@ static void get_toshiba_nand_para(struct denali_nand_info *denali)
 
 static void get_hynix_nand_para(struct denali_nand_info *denali, u8 device_id)
 {
-	u32 main_size, spare_size;
-
 	switch (device_id) {
 	case 0xD5: /* Hynix H27UAG8T2A, H27UBG8U5A or H27UCG8VFA */
 	case 0xD7: /* Hynix H27UDG8VEM, H27UCG8UDM or H27UCG8V5A */
 		iowrite32(128, denali->flash_reg + PAGES_PER_BLOCK);
 		iowrite32(4096, denali->flash_reg + DEVICE_MAIN_AREA_SIZE);
 		iowrite32(224, denali->flash_reg + DEVICE_SPARE_AREA_SIZE);
-		main_size = 4096 *
-			ioread32(denali->flash_reg + DEVICES_CONNECTED);
-		spare_size = 224 *
-			ioread32(denali->flash_reg + DEVICES_CONNECTED);
-		iowrite32(main_size,
-				denali->flash_reg + LOGICAL_PAGE_DATA_SIZE);
-		iowrite32(spare_size,
-				denali->flash_reg + LOGICAL_PAGE_SPARE_SIZE);
 		iowrite32(0, denali->flash_reg + DEVICE_WIDTH);
 #if SUPPORT_15BITECC
 		iowrite32(15, denali->flash_reg + ECC_CORRECTION);
-- 
2.7.4