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 --- drivers/ram/rockchip/sdram_rk3399.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/drivers/ram/rockchip/sdram_rk3399.c b/drivers/ram/rockchip/sdram_rk3399.c index 4d2310cbe6..0a5152c710 100644 --- a/drivers/ram/rockchip/sdram_rk3399.c +++ b/drivers/ram/rockchip/sdram_rk3399.c @@ -550,6 +550,20 @@ static int pctl_cfg(struct dram_info *dram, const struct chan_info *chan, 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, ¶ms->pi_regs.denali_pi[0], sizeof(struct rk3399_ddr_pi_regs));