mtd: nand: sunxi: Set serial access mode correctly
authorRoy Spliet <r.spliet@ultimaker.com>
Fri, 26 Jun 2015 09:00:11 +0000 (11:00 +0200)
committerBrian Norris <computersforpeace@gmail.com>
Mon, 20 Jul 2015 17:45:53 +0000 (10:45 -0700)
Replaces the hard coded "always use EDO" policy with that prescribed
by the ONFI 3.1 specification that EDO mode should always be used if tRC
is below 30ns.

Signed-off-by: Roy Spliet <r.spliet@ultimaker.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
drivers/mtd/nand/sunxi_nand.c

index 663e3314bb83d89937fcb7c5f49a280dad6e3994..f97a58d6aae1bbbacdb29ca86ac30c1f21d19e48 100644 (file)
@@ -99,6 +99,9 @@
                                 NFC_CMD_INT_ENABLE | \
                                 NFC_DMA_INT_ENABLE)
 
+/* define bit use in NFC_TIMING_CTL */
+#define NFC_TIMING_CTL_EDO     BIT(8)
+
 /* define NFC_TIMING_CFG register layout */
 #define NFC_TIMING_CFG(tWB, tADL, tWHR, tRHW, tCAD)            \
        (((tWB) & 0x3) | (((tADL) & 0x3) << 2) |                \
@@ -225,6 +228,7 @@ struct sunxi_nand_chip {
        struct mtd_info mtd;
        unsigned long clk_rate;
        u32 timing_cfg;
+       u32 timing_ctl;
        int selected;
        int nsels;
        struct sunxi_nand_chip_sel sels[0];
@@ -411,6 +415,7 @@ static void sunxi_nfc_select_chip(struct mtd_info *mtd, int chip)
                }
        }
 
+       writel(sunxi_nand->timing_ctl, nfc->regs + NFC_REG_TIMING_CTL);
        writel(sunxi_nand->timing_cfg, nfc->regs + NFC_REG_TIMING_CFG);
        writel(ctl, nfc->regs + NFC_REG_CTL);
 
@@ -940,6 +945,13 @@ static int sunxi_nand_chip_set_timings(struct sunxi_nand_chip *chip,
        /* TODO: A83 has some more bits for CDQSS, CS, CLHZ, CCS, WC */
        chip->timing_cfg = NFC_TIMING_CFG(tWB, tADL, tWHR, tRHW, tCAD);
 
+       /*
+        * ONFI specification 3.1, paragraph 4.15.2 dictates that EDO data
+        * output cycle timings shall be used if the host drives tRC less than
+        * 30 ns.
+        */
+       chip->timing_ctl = (timings->tRC_min < 30000) ? NFC_TIMING_CTL_EDO : 0;
+
        /* Convert min_clk_period from picoseconds to nanoseconds */
        min_clk_period = DIV_ROUND_UP(min_clk_period, 1000);
 
@@ -1441,11 +1453,6 @@ static int sunxi_nfc_probe(struct platform_device *pdev)
 
        platform_set_drvdata(pdev, nfc);
 
-       /*
-        * TODO: replace this magic value with EDO flag
-        */
-       writel(0x100, nfc->regs + NFC_REG_TIMING_CTL);
-
        ret = sunxi_nand_chips_init(dev, nfc);
        if (ret) {
                dev_err(dev, "failed to init nand chips\n");