ddr: socfpga: Clean up ddr_setup()

Replace the current rather convoluted code using ad-hoc polling
mechanism with a more straightforward code. Use wait_for_bit_le32()
to poll the DDRCALSTAT register instead of local reimplementation.
It makes no sense to pull for 5 seconds before giving up and trying
to restart the EMIF, so instead wait 500 mSec for the calibration to
complete and if this fails, restart the EMIF and try again. Perform
this 32 times instead of 3 times as the original code did.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Chin Liang See <chin.liang.see@intel.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Cc: Tien Fong Chee <tien.fong.chee@intel.com>

diff --git a/drivers/ddr/altera/sdram_arria10.c b/drivers/ddr/altera/sdram_arria10.c
index ff83c6100273a80cacc141402479c3c5880f47e3..1777e7e1a50e8caf6ebbda79d28a547f9ff17e0e 100644 (file)
--- a/drivers/ddr/altera/sdram_arria10.c
+++ b/drivers/ddr/altera/sdram_arria10.c
@@ -102,12 +102,6 @@ static int match_ddr_conf(u32 ddr_conf)
        return 0;
 }
 
-/* Check whether SDRAM is successfully Calibrated */
-static int is_sdram_cal_success(void)
-{
-       return readl(&socfpga_ecc_hmc_base->ddrcalstat);
-}
-
 static int emif_clear(void)
 {
        writel(0, DDR_REG_CORE2SEQ);
@@ -167,30 +161,23 @@ static int emif_reset(void)
 
 static int ddr_setup(void)
 {
-       int i, j, ddr_setup_complete = 0;
-
-       /* Try 3 times to do a calibration */
-       for (i = 0; (i < 3) && !ddr_setup_complete; i++) {
-               WATCHDOG_RESET();
-
-               /* A delay to wait for calibration bit to set */
-               for (j = 0; (j < 10) && !ddr_setup_complete; j++) {
-                       mdelay(500);
-                       ddr_setup_complete = is_sdram_cal_success();
-               }
-
-               if (!ddr_setup_complete)
-                       if (emif_reset())
-                               puts("Error: Failed to reset EMIF\n");
+       int i, ret;
+
+       /* Try 32 times to do a calibration */
+       for (i = 0; i < 32; i++) {
+               mdelay(500);
+               ret = wait_for_bit_le32(&socfpga_ecc_hmc_base->ddrcalstat,
+                                       BIT(0), true, 500, false);
+               if (!ret)
+                       return 0;
+
+               ret = emif_reset();
+               if (ret)
+                       puts("Error: Failed to reset EMIF\n");
        }
 
-       /* After 3 times trying calibration */
-       if (!ddr_setup_complete) {
-               puts("Error: Could Not Calibrate SDRAM\n");
-               return -EPERM;
-       }
-
-       return 0;
+       puts("Error: Could Not Calibrate SDRAM\n");
+       return -EPERM;
 }
 
 static int sdram_is_ecc_enabled(void)