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Commit 959e9f2a authored by Masahiro Yamada's avatar Masahiro Yamada Committed by Boris Brezillon
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mtd: nand: denali: remove unneeded find_valid_banks() 



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: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
parent b21ff825

drivers/mtd/nand/denali.c

+0 −47
Original line number Diff line number Diff line
@@ -337,51 +337,6 @@ 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.

drivers/mtd/nand/denali.h

+0 −1
Original line number Diff line number Diff line
@@ -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 */