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mtd: rawnand: denali: remove denali_reset_banks()

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In nand_scan_ident(), the controller driver resets every NAND chip.
This is done by sending NAND_CMD_RESET. The Denali IP provides
another way to do the equivalent thing; if a bit is set in the
DEVICE_RESET register, the controller sends the RESET command to
the corresponding device. denali_reset_banks() uses it to reset
all devices beforehand.

This redundant reset sequence was needed to know the actual number
of chips before calling nand_scan_ident(); if DEVICE_RESET fails,
there is no chip in that chip select. Then, denali_reset_banks()
sets denali->max_banks to the number of detected chips.

As commit f486287d23 ("mtd: nand: denali: fix bank reset function
to detect the number of chips") explained, nand_scan_ident() issued
Set Features (0xEF) command to all CS lines, some of which may not be
connected with a chip. Then, the driver would wait for R/B# response,
which never happens.

This problem was solved by commit 107b7d6a7a ("mtd: rawnand: avoid
setting again the timings to mode 0 after a reset"). In the current
code, nand_setup_data_interface() is called from nand_scan_tail(),
which is invoked after the chip detection.

Now, we can really remove the redundant denali_nand_banks() by simply
passing the maximum number of chip selects supported by this IP
(typically 4 or 8) to nand_scan(). Let's leave all the chip detection
process to nand_scan_ident().

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
This commit is contained in:
Masahiro Yamada 2018-11-28 14:27:37 +09:00 committed by Miquel Raynal
parent a2a05c2f53
commit 5fb3dc1147
1 changed files with 0 additions and 29 deletions
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29
drivers/mtd/nand/raw/denali.c
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@ -1045,29 +1045,6 @@ static int denali_setup_data_interface(struct nand_chip *chip, int chipnr,
return 0;
}
static void denali_reset_banks(struct denali_nand_info *denali)
{
u32 irq_status;
int i;
for (i = 0; i < denali->max_banks; i++) {
denali->active_bank = i;
denali_reset_irq(denali);
iowrite32(DEVICE_RESET__BANK(i),
denali->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;
}
static void denali_hw_init(struct denali_nand_info *denali)
{
/*
@ -1322,12 +1299,6 @@ int denali_init(struct denali_nand_info *denali)
}
denali_enable_irq(denali);
denali_reset_banks(denali);
if (!denali->max_banks) {
/* Error out earlier if no chip is found for some reasons. */
ret = -ENODEV;
goto disable_irq;
}
denali->active_bank = DENALI_INVALID_BANK;