From: Stefan Agner <stefan@agner.ch>
To: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: dwmw2@infradead.org, computersforpeace@gmail.com,
mark.rutland@arm.com, boris.brezillon@free-electrons.com,
aaron@tastycactus.com, marb@ixxat.de, pawel.moll@arm.com,
ijc+devicetree@hellion.org.uk, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org, robh+dt@kernel.org,
linux-mtd@lists.infradead.org, kernel@pengutronix.de,
galak@codeaurora.org, shawn.guo@linaro.org,
linux-arm-kernel@lists.infradead.org, bpringlemeir@nbsps.com
Subject: Re: [PATCH v4 1/6] mtd: nand: vf610_nfc: Freescale NFC for VF610, MPC5125 and others
Date: Wed, 03 Jun 2015 17:05:16 +0200 [thread overview]
Message-ID: <b3b09b4b8c97cbfc88fa0d5fdc5e40cd@agner.ch> (raw)
In-Reply-To: <20150603130825.GA23991@breakpoint.cc>
On 2015-06-03 15:08, Sebastian Andrzej Siewior wrote:
> On 2015-03-25 17:28:24 [+0100], Stefan Agner wrote:
>> diff --git a/drivers/mtd/nand/vf610_nfc.c b/drivers/mtd/nand/vf610_nfc.c
>> new file mode 100644
>> index 0000000..23c1510
>> --- /dev/null
>> +++ b/drivers/mtd/nand/vf610_nfc.c
>> @@ -0,0 +1,686 @@
> …
>> +static inline u32 vf610_nfc_read(struct vf610_nfc *nfc, uint reg)
>> +{
>> + return readl(nfc->regs + reg);
>> +}
>> +
>> +static inline void vf610_nfc_write(struct vf610_nfc *nfc, uint reg, u32 val)
>> +{
>> + writel(val, nfc->regs + reg);
>> +}
> …
>
>> +static void vf610_nfc_send_command(struct vf610_nfc *nfc, u32 cmd_byte1,
>> + u32 cmd_code)
>> +{
>> + void __iomem *reg = nfc->regs + NFC_FLASH_CMD2;
>> + u32 tmp;
>> +
>> + vf610_nfc_clear_status(nfc);
>> +
>> + tmp = __raw_readl(reg);
>> + tmp &= ~(CMD_BYTE1_MASK | CMD_CODE_MASK | BUFNO_MASK);
>> + tmp |= cmd_byte1 << CMD_BYTE1_SHIFT;
>> + tmp |= cmd_code << CMD_CODE_SHIFT;
>> + __raw_writel(tmp, reg);
>> +}
>
> Why readl() vs __raw_readl() dito for write?
> vf610_nfc_{read|write} is good since for PPC we would need out_be32()
> here instead.
> It would be nice if you could abstract the __raw_ once as well. And I am
> not sure if you need those at all since the former functions should work
> here just fine.
As Boris guessed correctly, the reason I used the raw variant was due to
performance improvements due to the barrier. However, I will use
{read|write}l_relaxed instead, which should offer endian abstraction
while not having the performance penalty due to extensive barriers...
--
Stefan
next prev parent reply other threads:[~2015-06-03 15:07 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-25 16:28 [PATCH v4 0/6] mtd: nand: vf610_nfc: Freescale NFC for VF610 Stefan Agner
2015-03-25 16:28 ` [PATCH v4 1/6] mtd: nand: vf610_nfc: Freescale NFC for VF610, MPC5125 and others Stefan Agner
2015-06-02 1:32 ` Brian Norris
2015-06-02 9:01 ` Stefan Agner
2015-06-03 8:10 ` Sebastian Andrzej Siewior
2015-06-03 9:45 ` Stefan Agner
2015-06-03 12:03 ` Sebastian Andrzej Siewior
2015-06-03 15:09 ` Stefan Agner
2015-06-09 20:05 ` Sebastian Andrzej Siewior
2015-06-03 13:08 ` Sebastian Andrzej Siewior
2015-06-03 15:05 ` Stefan Agner [this message]
2015-06-09 20:07 ` Sebastian Andrzej Siewior
2015-06-09 20:31 ` Stefan Agner
2015-06-12 19:44 ` Sebastian Andrzej Siewior
2015-06-17 13:02 ` Stefan Agner
2015-06-18 18:27 ` Sebastian Andrzej Siewior
2015-03-25 16:28 ` [PATCH v4 2/6] mtd: nand: vf610_nfc: add hardware BCH-ECC support Stefan Agner
2015-03-25 16:28 ` [PATCH v4 3/6] mtd: nand: vf610_nfc: add device tree bindings Stefan Agner
2015-03-25 16:28 ` [PATCH v4 4/6] ARM: vf610: enable NAND Flash Controller Stefan Agner
2015-03-25 16:28 ` [PATCH v4 5/6] ARM: dts: vf610: add NAND flash controller peripherial Stefan Agner
2015-03-25 16:28 ` [PATCH v4 6/6] ARM: dts: vf-colibri: enable NAND flash controller Stefan Agner
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