driver/mtd:IFC NAND:Initialise internal SRAM before any write

IFC-1.1.0 uses 28nm techenology for SRAM. This tech has known limitaion for
SRAM i.e. "byte select" is not supported. Hence Read Modify Write is
implemented in IFC for any "system side write" into sram buffer. Reading an
uninitialized memory results in ECC Error from sram wrapper.

Hence we must initialize/prefill SRAM buffer by any data before writing
anything in SRAM from system side. To initialize SRAM user can use "READID"
NAND command with read bytes equal to SRAM size. It will be a one time
activity post boot

Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
[scottwood@freescale.com: fix fsl_ifc_sram_init prototype]
Signed-off-by: Scott Wood <scottwood@freescale.com>

drivers/mtd/nand/fsl_ifc_nand.c

@@ -30,6 +30,7 @@
 #include <asm/errno.h>
 #include <asm/fsl_ifc.h>
 
+#define FSL_IFC_V1_1_0	0x01010000
 #define MAX_BANKS	4
 #define ERR_BYTE	0xFF /* Value returned for read bytes
 				when read failed */
@@ -738,11 +739,66 @@ static void fsl_ifc_select_chip(struct mtd_info *mtd, int chip)
 {
 }
 
+static void fsl_ifc_sram_init(void)
+{
+	struct fsl_ifc *ifc = ifc_ctrl->regs;
+	uint32_t cs = 0, csor = 0, csor_8k = 0, csor_ext = 0;
+	long long end_tick;
+
+	cs = ifc_ctrl->cs_nand >> IFC_NAND_CSEL_SHIFT;
+
+	/* Save CSOR and CSOR_ext */
+	csor = in_be32(&ifc_ctrl->regs->csor_cs[cs].csor);
+	csor_ext = in_be32(&ifc_ctrl->regs->csor_cs[cs].csor_ext);
+
+	/* chage PageSize 8K and SpareSize 1K*/
+	csor_8k = (csor & ~(CSOR_NAND_PGS_MASK)) | 0x0018C000;
+	out_be32(&ifc_ctrl->regs->csor_cs[cs].csor, csor_8k);
+	out_be32(&ifc_ctrl->regs->csor_cs[cs].csor_ext, 0x0000400);
+
+	/* READID */
+	out_be32(&ifc->ifc_nand.nand_fir0,
+			(IFC_FIR_OP_CMD0 << IFC_NAND_FIR0_OP0_SHIFT) |
+			(IFC_FIR_OP_UA  << IFC_NAND_FIR0_OP1_SHIFT) |
+			(IFC_FIR_OP_RB << IFC_NAND_FIR0_OP2_SHIFT));
+	out_be32(&ifc->ifc_nand.nand_fcr0,
+			NAND_CMD_READID << IFC_NAND_FCR0_CMD0_SHIFT);
+	out_be32(&ifc->ifc_nand.row3, 0x0);
+
+	out_be32(&ifc->ifc_nand.nand_fbcr, 0x0);
+
+	/* Program ROW0/COL0 */
+	out_be32(&ifc->ifc_nand.row0, 0x0);
+	out_be32(&ifc->ifc_nand.col0, 0x0);
+
+	/* set the chip select for NAND Transaction */
+	out_be32(&ifc->ifc_nand.nand_csel, ifc_ctrl->cs_nand);
+
+	/* start read seq */
+	out_be32(&ifc->ifc_nand.nandseq_strt, IFC_NAND_SEQ_STRT_FIR_STRT);
+
+	/* wait for NAND Machine complete flag or timeout */
+	end_tick = usec2ticks(IFC_TIMEOUT_MSECS * 1000) + get_ticks();
+
+	while (end_tick > get_ticks()) {
+		ifc_ctrl->status = in_be32(&ifc->ifc_nand.nand_evter_stat);
+
+		if (ifc_ctrl->status & IFC_NAND_EVTER_STAT_OPC)
+			break;
+	}
+
+	out_be32(&ifc->ifc_nand.nand_evter_stat, ifc_ctrl->status);
+
+	/* Restore CSOR and CSOR_ext */
+	out_be32(&ifc_ctrl->regs->csor_cs[cs].csor, csor);
+	out_be32(&ifc_ctrl->regs->csor_cs[cs].csor_ext, csor_ext);
+}
+
 int board_nand_init(struct nand_chip *nand)
 {
 	struct fsl_ifc_mtd *priv;
 	struct nand_ecclayout *layout;
-	uint32_t cspr = 0, csor = 0;
+	uint32_t cspr = 0, csor = 0, ver = 0;
 
 	if (!ifc_ctrl) {
 		fsl_ifc_ctrl_init();
@@ -861,5 +917,9 @@ int board_nand_init(struct nand_chip *nand)
 		nand->ecc.mode = NAND_ECC_SOFT;
 	}
 
+	ver = in_be32(&ifc_ctrl->regs->ifc_rev);
+	if (ver == FSL_IFC_V1_1_0)
+		fsl_ifc_sram_init();
+
 	return 0;
 }