Messages in this thread | | | Date | Wed, 03 Jun 2015 17:05:16 +0200 | From | Stefan Agner <> | Subject | Re: [PATCH v4 1/6] mtd: nand: vf610 nfc: Fr eescale NFC for VF610, MPC5125 and others |
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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
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