[PATCH v4 1/6] mtd: nand: vf610_nfc: Freescale NFC for VF610, MPC5125 and others
From: stefan@agner.ch (Stefan Agner)
Date: 2015-06-03 15:07:23
Also in:
linux-devicetree, lkml
On 2015-06-03 15:08, Sebastian Andrzej Siewior wrote:
On 2015-03-25 17:28:24 [+0100], Stefan Agner wrote:quoted
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 @@?quoted
+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); +}?quoted
+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