Hi Bernard, On 5/7/20 12:45 PM, Bernard Zhao wrote:
In function create_timings_aligned, all the max is to use dmc->min_tck->xxx, aligned with val dmc->timings->xxx. But the dmc->timings->tFAW use dmc->min_tck->tXP? Maybe this point is wrong parameter useing. Signed-off-by: Bernard Zhao <bernard@xxxxxxxx> --- drivers/memory/samsung/exynos5422-dmc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/memory/samsung/exynos5422-dmc.c b/drivers/memory/samsung/exynos5422-dmc.c index 81a1b1d01683..22a43d662833 100644 --- a/drivers/memory/samsung/exynos5422-dmc.c +++ b/drivers/memory/samsung/exynos5422-dmc.c @@ -1091,7 +1091,7 @@ static int create_timings_aligned(struct exynos5_dmc *dmc, u32 *reg_timing_row, /* power related timings */ val = dmc->timings->tFAW / clk_period_ps; val += dmc->timings->tFAW % clk_period_ps ? 1 : 0; - val = max(val, dmc->min_tck->tXP); + val = max(val, dmc->min_tck->tFAW); reg = &timing_power[0]; *reg_timing_power |= TIMING_VAL2REG(reg, val);
Good catch! Indeed this should be a dmc->min_tck->tFAW used for clamping. It didn't show up in testing because the frequency values based on which the 'clk_period_ps' are calculated are sane. Check the dump below: [ 5.458227] DMC: mem tFAW=25000, clk_period_ps=6060 [ 5.461743] DMC: tFAW=5, tXP=2 val=5 [ 5.465273] DMC: mem tFAW=25000, clk_period_ps=4854 [ 5.470101] DMC: tFAW=5, tXP=2 val=6 [ 5.473668] DMC: mem tFAW=25000, clk_period_ps=3636 [ 5.478507] DMC: tFAW=5, tXP=2 val=7 [ 5.482072] DMC: mem tFAW=25000, clk_period_ps=2421 [ 5.486951] DMC: tFAW=5, tXP=2 val=11 [ 5.490531] DMC: mem tFAW=25000, clk_period_ps=1841 [ 5.495439] DMC: tFAW=5, tXP=2 val=14 [ 5.499113] DMC: mem tFAW=25000, clk_period_ps=1579 [ 5.503877] DMC: tFAW=5, tXP=2 val=16 [ 5.507476] DMC: mem tFAW=25000, clk_period_ps=1373 [ 5.512368] DMC: tFAW=5, tXP=2 val=19 [ 5.515968] DMC: mem tFAW=25000, clk_period_ps=1212 [ 5.520826] DMC: tFAW=5, tXP=2 val=21 That's why in the existing configuration it does not harm (the calculated 'val' is always >= 5) the board. But I think this patch should be applied (after small changes in the commit message). @Krzysztof could you have a look on the commit message or take the patch with small adjustment in the description, please? I conditionally give (because of this description): Reviewed-by: Lukasz Luba <lukasz.luba@xxxxxxx> Thank you Bernard for reporting and fixing this. Regards, Lukasz
