From: b32955@freescale•com (Huang Shijie)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH V1 3/5] mtd: m25p80: add the quad-read support
Date: Fri, 23 Aug 2013 17:25:21 +0800 [thread overview]
Message-ID: <52172A81.5090501@freescale.com> (raw)
In-Reply-To: <CAHSAbzN166J=DFi+1koPUpnFpJVHwtbC1AP21ywhAAissQxPxg@mail.gmail.com>
? 2013?08?23? 17:05, yuhang wang ??:
>> + u16 sr_cr;
>> > + int ret;
>> >
>> > #ifdef CONFIG_MTD_OF_PARTS
>> > if (!of_device_is_available(np))
>> > @@ -1014,6 +1050,21 @@ static int m25p_probe(struct spi_device *spi)
>> > else
>> > flash->read_opcode = OPCODE_NORM_READ;
>> >
>> > + /* Try to enable the Quad Read */
>> > + if (np&& of_property_read_bool(np, "m25p,quad-read")) {
>> > + /* The configuration register is set by the second byte. */
>> > + sr_cr = CR_QUAD<< 8;
>> > +
>> > + /* Write the QUAD bit to the Configuration Register. */
>> > + write_enable(flash);
>> > + if (write_sr_cr(flash, sr_cr) == 0) {
>> > + /* read back and check it */
>> > + ret = read_cr(flash);
>> > + if (ret> 0&& (ret& CR_QUAD))
>> > + flash->read_opcode = OPCODE_QIOR;
>> > + }
>> > + }
>> > +
> Well, M25p80.c support lots of flash devices, so driver should be as
> general as possible. Firstly not all the devices m25p80 supports set
> quad mode as your sequence, perhaps write_sr_cr can not match all the
It does not matter the NOR flash supports the write_sr_cr() or not,
If the NOR flash does not support the write_sr_cr(), it may fails, and
you will not set the OPCODE_QIOR for the
m25p80_read.
> m25p80 flash. Secondly, why you only support QIOR(high performance)
> not QOR or DOR. Maybe QIOR seems too special, so what if user want to
> use QOR if he set quad mode in DTS.
>
Frankly speaking, i am reluctant to support the QIOR, it is a little
slow. :)
So the the QIOR is lowest speed for QUADSPI controller, and i do not
want to support the DOR.
In my new version, i add the support for DDR QIOR read which is the
double rate of the QIOR.
The user should knows if the NOR flash supports the quad-read or not,
and set the proper DT.
> Another point, if command changed to OPCODE_QIOR, there should also
> should be some correct in m25p_read. such as the number of dummy data.
I only need to change the read opcode.
> QIOR can support read without read command if set the certain bit in
> transfer, these aspects did not reflect in your patch.
>
For the Quadspi, it will handle the dummy by the LUT sequence, such as
DDR QUAD read, the LUT sequence will
set proper dummy (6 cycles for S25FL128S). I do not need the m25p_read
to set the dummy.
thanks
Huang Shijie
next prev parent reply other threads:[~2013-08-23 9:25 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-19 4:09 [PATCH V1 0/5] Add the Quadspi driver for vf610-twr Huang Shijie
2013-08-19 4:09 ` [PATCH V1 1/5] mtd: m25p80: move the spi-nor commands to a header Huang Shijie
2013-08-19 4:10 ` [PATCH V1 2/5] mtd: m25p80: add support for Spansion s25fl128s chip Huang Shijie
2013-08-19 4:10 ` [PATCH V1 3/5] mtd: m25p80: add the quad-read support Huang Shijie
2013-08-22 19:34 ` Brian Norris
2013-08-22 19:55 ` Mark Brown
2013-08-22 20:29 ` Marek Vasut
2013-08-22 23:36 ` Mark Brown
2013-08-22 23:58 ` Marek Vasut
2013-08-23 9:41 ` Mark Brown
2013-08-23 10:42 ` Marek Vasut
2013-08-23 11:46 ` Brian Norris
2013-08-23 11:53 ` Brian Norris
2013-08-23 12:01 ` Mark Brown
2013-08-23 13:20 ` yuhang wang
2013-08-23 6:26 ` Huang Shijie
2013-08-23 11:23 ` Brian Norris
2013-08-23 11:27 ` Sourav Poddar
2013-08-23 11:30 ` Mark Brown
2013-08-23 9:05 ` yuhang wang
2013-08-23 9:25 ` Huang Shijie [this message]
2013-08-23 9:57 ` Sourav Poddar
2013-08-24 2:45 ` Huang Shijie
2013-08-23 15:59 ` Sourav Poddar
2013-08-23 13:59 ` yuhang wang
2013-08-24 3:01 ` Huang Shijie
2013-08-19 4:10 ` [PATCH V1 4/5] spi: Add Freescale QuadSpi driver Huang Shijie
2013-08-22 19:21 ` Brian Norris
2013-08-23 2:14 ` Huang Shijie
2013-08-23 6:59 ` Huang Shijie
2013-08-23 16:44 ` Mark Brown
2013-08-24 7:11 ` Brian Norris
2013-08-24 13:42 ` Huang Shijie
2013-08-19 4:10 ` [PATCH V1 5/5] ARM: dts: vf610-twr: Add SPI NOR support Huang Shijie
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