[U-Boot] [RFC 4/4] MXC: Reorganize 16 bit nand detection.

[Magnus Lilja]

Alternative solution for supporting 16 bit NAND detection for the
i.MX27 and i.MX31 SoCs. This moves the SoC specific code to the SoC header
file leaving mxc_nand.c free from #ifdef's (in this respect).

Question:
Is this approach acceptable/preferred over having #ifdef's for different
SoCs in mxc_nand.c?
---
 drivers/mtd/nand/mxc_nand.c           |   12 ++----------
 include/asm-arm/arch-mx27/imx-regs.h  |   13 +++++++++++++
 include/asm-arm/arch-mx31/mx31-regs.h |   13 +++++++++++++
 3 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c
index 3e4254a..45d0024 100644
--- a/drivers/mtd/nand/mxc_nand.c
+++ b/drivers/mtd/nand/mxc_nand.c
@@ -808,8 +808,6 @@ static void mxc_nand_command(struct mtd_info *mtd, unsigned command,
 
 int board_nand_init(struct nand_chip *this)
 {
-	struct system_control_regs *sc_regs =
-		(struct system_control_regs *)IMX_SYSTEM_CTL_BASE;
 	struct mtd_info *mtd;
 	uint16_t tmp;
 	int err = 0;
@@ -871,15 +869,9 @@ int board_nand_init(struct nand_chip *this)
 	writew(0x4, &host->regs->nfc_wrprot);
 
 	/* NAND bus width determines access funtions used by upper layer */
-#ifdef CONFIG_MX27
-	if (readl(&sc_regs->fmcr) & NF_16BIT_SEL)
-		this->options |= NAND_BUSWIDTH_16;
-#elif defined(CONFIG_MX31)
-	if (readl(&sc_regs->rcsr) & CCM_RCSR_NF16B)
+	if (mxc_nand_is_16bit())
 		this->options |= NAND_BUSWIDTH_16;
-#else
-#warning "No autodetection of 8/16 bit NAND"
-#endif
+
 	host->pagesize_2k = 0;
 
 	return err;
diff --git a/include/asm-arm/arch-mx27/imx-regs.h b/include/asm-arm/arch-mx27/imx-regs.h
index d36a6da..b88fe51 100644
--- a/include/asm-arm/arch-mx27/imx-regs.h
+++ b/include/asm-arm/arch-mx27/imx-regs.h
@@ -516,4 +516,17 @@ struct iim_regs {
 #define IIM0_SCC_KEY		11
 #define IIM1_SUID		1
 
+#ifndef __ASSEMBLY__
+static inline int mxc_nand_is_16bit(void)
+{
+	struct system_control_regs *sc_regs =
+		(struct system_control_regs *)IMX_SYSTEM_CTL_BASE;
+
+	if (readl(&sc_regs->rcsr) & CCM_RCSR_NF16B)
+		return 1;
+	else
+		return 0;
+}
+#endif
+
 #endif				/* _IMX_REGS_H */
diff --git a/include/asm-arm/arch-mx31/mx31-regs.h b/include/asm-arm/arch-mx31/mx31-regs.h
index 86c9975..613c632 100644
--- a/include/asm-arm/arch-mx31/mx31-regs.h
+++ b/include/asm-arm/arch-mx31/mx31-regs.h
@@ -63,6 +63,19 @@ struct system_control_regs {
 #define CCM_RCSR_NF16B	(1 << 31)
 #define CCM_RCSR_NFMS	(1 << 30)
 
+#include <asm/io.h>
+
+static inline int mxc_nand_is_16bit(void)
+{
+	struct system_control_regs *sc_regs =
+		(struct system_control_regs *)IMX_SYSTEM_CTL_BASE;
+
+	if (readl(&sc_regs->rcsr) & CCM_RCSR_NF16B)
+		return 1;
+	else
+		return 0;
+}
+
 #endif
 
 #define __REG(x)     (*((volatile u32 *)(x)))
-- 
1.5.6