mtd: gpmi: add a new field for HW_GPMI_TIMING1

The gpmi_nfc_compute_hardware_timing{} should contains all the
fields setting for gpmi timing registers. It already contains the fields
for HW_GPMI_TIMING0 and HW_GPMI_CTRL1.

So it is better to add a new field setting for HW_GPMI_TIMING1 in
this data structure. This makes the code more clear in logic.

This patch also changes some comments to make the code more readable.
Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/gpmi-nand/gpmi-lib.c

@@ -728,6 +728,7 @@ static int gpmi_nfc_compute_hardware_timing(struct gpmi_nand_data *this,
 	hw->address_setup_in_cycles = address_setup_in_cycles;
 	hw->use_half_periods        = dll_use_half_periods;
 	hw->sample_delay_factor     = sample_delay_factor;
+	hw->device_busy_timeout     = GPMI_DEFAULT_BUSY_TIMEOUT;
 
 	/* Return success. */
 	return 0;
@@ -752,26 +753,26 @@ void gpmi_begin(struct gpmi_nand_data *this)
 		goto err_out;
 	}
 
-	/* set ready/busy timeout */
-	writel(0x500 << BP_GPMI_TIMING1_BUSY_TIMEOUT,
-		gpmi_regs + HW_GPMI_TIMING1);
-
 	/* Get the timing information we need. */
 	nfc->clock_frequency_in_hz = clk_get_rate(r->clock[0]);
 	clock_period_in_ns = 1000000000 / nfc->clock_frequency_in_hz;
 
 	gpmi_nfc_compute_hardware_timing(this, &hw);
 
-	/* Set up all the simple timing parameters. */
+	/* [1] Set HW_GPMI_TIMING0 */
 	reg = BF_GPMI_TIMING0_ADDRESS_SETUP(hw.address_setup_in_cycles) |
 		BF_GPMI_TIMING0_DATA_HOLD(hw.data_hold_in_cycles)         |
 		BF_GPMI_TIMING0_DATA_SETUP(hw.data_setup_in_cycles)       ;
 
 	writel(reg, gpmi_regs + HW_GPMI_TIMING0);
 
-	/*
-	 * DLL_ENABLE must be set to 0 when setting RDN_DELAY or HALF_PERIOD.
-	 */
+	/* [2] Set HW_GPMI_TIMING1 */
+	writel(BF_GPMI_TIMING1_BUSY_TIMEOUT(hw.device_busy_timeout),
+		gpmi_regs + HW_GPMI_TIMING1);
+
+	/* [3] The following code is to set the HW_GPMI_CTRL1. */
+
+	/* DLL_ENABLE must be set to 0 when setting RDN_DELAY or HALF_PERIOD. */
 	writel(BM_GPMI_CTRL1_DLL_ENABLE, gpmi_regs + HW_GPMI_CTRL1_CLR);
 
 	/* Clear out the DLL control fields. */

drivers/mtd/nand/gpmi-nand/gpmi-nand.h

@@ -189,14 +189,24 @@ struct gpmi_nand_data {
  * @data_setup_in_cycles:      The data setup time, in cycles.
  * @data_hold_in_cycles:       The data hold time, in cycles.
  * @address_setup_in_cycles:   The address setup time, in cycles.
+ * @device_busy_timeout:       The timeout waiting for NAND Ready/Busy,
+ *                             this value is the number of cycles multiplied
+ *                             by 4096.
  * @use_half_periods:          Indicates the clock is running slowly, so the
  *                             NFC DLL should use half-periods.
  * @sample_delay_factor:       The sample delay factor.
  */
 struct gpmi_nfc_hardware_timing {
+	/* for HW_GPMI_TIMING0 */
 	uint8_t  data_setup_in_cycles;
 	uint8_t  data_hold_in_cycles;
 	uint8_t  address_setup_in_cycles;
+
+	/* for HW_GPMI_TIMING1 */
+	uint16_t device_busy_timeout;
+#define GPMI_DEFAULT_BUSY_TIMEOUT	0x500 /* default busy timeout value.*/
+
+	/* for HW_GPMI_CTRL1 */
 	bool     use_half_periods;
 	uint8_t  sample_delay_factor;
 };

drivers/mtd/nand/gpmi-nand/gpmi-regs.h

@@ -154,6 +154,9 @@
 
 #define HW_GPMI_TIMING1					0x00000080
 #define BP_GPMI_TIMING1_BUSY_TIMEOUT			16
+#define BM_GPMI_TIMING1_BUSY_TIMEOUT	(0xffff << BP_GPMI_TIMING1_BUSY_TIMEOUT)
+#define BF_GPMI_TIMING1_BUSY_TIMEOUT(v)		\
+	(((v) << BP_GPMI_TIMING1_BUSY_TIMEOUT) & BM_GPMI_TIMING1_BUSY_TIMEOUT)
 
 #define HW_GPMI_TIMING2					0x00000090
 #define HW_GPMI_DATA					0x000000a0