commit cc9da9ae17ebbe693347e450bfc98a61d827388a
author Jagan Teki <jagan@amarulasolutions.com> Tue Jul 16 17:27:13 2019 +0530
committer Kever Yang <kever.yang@rock-chips.com> Sat Jul 20 23:59:44 2019 +0800
tree 0eeebf670a608739d4bcae3349666e57f40b027e
parent 5e927184486d390f1287fd38b0f96f248edbc997

ram: rk3399: Avoid two channel ZQ Cal Start at the same time

It is possible in lpddr4 dram, where both the channels would
start at same time with ZQ Cal Start. If it uses ZQ Call start
then it will use RZQ.

For example LPDDR4 366 Dual-Die, Quad-Channel Package, RZQ maybe
connect to both channel. If ZQ Cal Start at the same time,
it will use the same RZQ.

It is not a problem of using RZQ in both the channels, but can not
use at the same time.

So, to avoid this, we have an option of dram tINIT3 value for
increasing the frequency for channel 1.

This patch increase the available tINIT3 with existing running
dram frequency.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: YouMin Chen <cym@rock-chips.com>
Reviewed-by: Kever Yang <Kever.yang@rock-chips.com>

drivers/ram/rockchip/sdram_rk3399.c

diff --git a/drivers/ram/rockchip/sdram_rk3399.c b/drivers/ram/rockchip/sdram_rk3399.c
index 6f6f382..8b2c6b3 100644
--- a/drivers/ram/rockchip/sdram_rk3399.c
+++ b/drivers/ram/rockchip/sdram_rk3399.c
@@ -550,6 +550,20 @@
 		    sizeof(struct rk3399_ddr_pctl_regs) - 4);
 	writel(params_ctl[0], &denali_ctl[0]);
 
+	/*
+	 * two channel init at the same time, then ZQ Cal Start
+	 * at the same time, it will use the same RZQ, but cannot
+	 * start at the same time.
+	 *
+	 * So, increase tINIT3 for channel 1, will avoid two
+	 * channel ZQ Cal Start at the same time
+	 */
+	if (params->base.dramtype == LPDDR4 && channel == 1) {
+		tmp = ((params->base.ddr_freq * MHz + 999) / 1000);
+		tmp1 = readl(&denali_ctl[14]);
+		writel(tmp + tmp1, &denali_ctl[14]);
+	}
+
 	copy_to_reg(denali_pi, &params->pi_regs.denali_pi[0],
 		    sizeof(struct rk3399_ddr_pi_regs));