linux-kernel - Re: [PATCH v3 3/8] clk: samsung: add BPLL rate table for Exynos 5422 SoC

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Message-ID: <59a5e9bc-a5de-9f98-5710-4cd48cb5b239@partner.samsung.com>
Date:   Mon, 11 Feb 2019 11:21:16 +0100
From:   Lukasz Luba <l.luba@...tner.samsung.com>
To:     cwchoi00@...il.com
Cc:     Chanwoo Choi <cw00.choi@...sung.com>,
        devicetree <devicetree@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Linux PM list <linux-pm@...r.kernel.org>,
        linux-samsung-soc <linux-samsung-soc@...r.kernel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Kukjin Kim <kgene@...nel.org>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Sylwester Nawrocki <s.nawrocki@...sung.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-clk@...r.kernel.org,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v3 3/8] clk: samsung: add BPLL rate table for Exynos
 5422 SoC

Hi Chanwoo,

On 2/3/19 8:54 AM, Chanwoo Choi wrote:
> Hi Lukasz,
> 
> 2019년 2월 1일 (금) 오후 11:22, Lukasz Luba <l.luba@...tner.samsung.com>님이 작성:
> 
>>
>> Hi Chanwoo,
>>
>> On 2/1/19 9:44 AM, Chanwoo Choi wrote:
>>> Hi,
>>>
>>> On 19. 1. 31. 오후 5:49, Lukasz Luba wrote:
>>>> Add new table rate for BPLL for Exynos5422 SoC supporting Dynamic Memory
>>>> Controller frequencies for driver's DRAM timings.
>>>>
>>>> CC: Sylwester Nawrocki <s.nawrocki@...sung.com>
>>>> CC: Chanwoo Choi <cw00.choi@...sung.com>
>>>> CC: Michael Turquette <mturquette@...libre.com>
>>>> CC: Stephen Boyd <sboyd@...nel.org>
>>>> CC: Kukjin Kim <kgene@...nel.org>
>>>> CC: Krzysztof Kozlowski <krzk@...nel.org>
>>>> CC: linux-samsung-soc@...r.kernel.org
>>>> CC: linux-clk@...r.kernel.org
>>>> CC: linux-arm-kernel@...ts.infradead.org
>>>> CC: linux-kernel@...r.kernel.org
>>>> Signed-off-by: Lukasz Luba <l.luba@...tner.samsung.com>
>>>> ---
>>>>    drivers/clk/samsung/clk-exynos5420.c | 15 ++++++++++++++-
>>>>    1 file changed, 14 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/clk/samsung/clk-exynos5420.c b/drivers/clk/samsung/clk-exynos5420.c
>>>> index 3e87421..8bf9579 100644
>>>> --- a/drivers/clk/samsung/clk-exynos5420.c
>>>> +++ b/drivers/clk/samsung/clk-exynos5420.c
>>>> @@ -1325,6 +1325,19 @@ static const struct samsung_pll_rate_table exynos5420_pll2550x_24mhz_tbl[] __ini
>>>>       PLL_35XX_RATE(24 * MHZ, 200000000,  200, 3, 3),
>>>>    };
>>>>
>>>> +static const struct samsung_pll_rate_table exynos5422_bpll_rate_table[] = {
>>>> +    PLL_35XX_RATE(24 * MHZ, 933000000, 311, 4, 1),
>>>> +    PLL_35XX_RATE(24 * MHZ, 825000000, 275, 4, 1),
>>>> +    PLL_35XX_RATE(24 * MHZ, 728000000, 182, 3, 1),
>>>> +    PLL_35XX_RATE(24 * MHZ, 633000000, 211, 4, 1),
>>>> +    PLL_35XX_RATE(24 * MHZ, 543000000, 181, 2, 2),
>>>> +    PLL_35XX_RATE(24 * MHZ, 413000000, 413, 6, 2),
>>>> +    PLL_35XX_RATE(24 * MHZ, 275000000, 275, 3, 3),
>>>> +    PLL_35XX_RATE(24 * MHZ, 206000000, 206, 3, 3),
>>>> +    PLL_35XX_RATE(24 * MHZ, 165000000, 110, 2, 3),
>>>> +    PLL_35XX_RATE(24 * MHZ, 138000000, 184, 2, 4),
>>>
>>> Except for 825Mhz, I can't find the target frequency
>>> on Exynos5422 TRM document. Usually, Exynos TRM specified
>>> the supported stable clocks. It means that undefined clocks
>>> are not stable as I knew. Where do you find them?
>>>
>>> When I calculated the PLL frequency with PMS value, it is correct.
>>> But, just we need to check the reference of undefined clocks on TRM
>>> in order to guarantee the stable operation.
>> They values live in vendor code for Android.
>> I have tested the DMC & DDR with these ratios in stress scenarios
>> for a few days and it was stable.
> 
> If possible, please share the url of original vendor code.
Here is the vendor code for the BPLL values:
https://github.com/hardkernel/linux/blob/odroidxu3-3.10.y-android/drivers/clk/samsung/clk-exynos5422.c#L2026

Regards,
Lukasz
> 
>>
>>>
>>> Remove 933/138Mhz because exynos5433-dmc.c doesn't use 933Mhz and 138Mhz
>>> and also Exynos5422 TRM doesn't define 933/138Mhz on pll table.
>> OK, I will remove them.
>>>
>>>> +};
>>>> +
>>>>    static const struct samsung_pll_rate_table exynos5420_epll_24mhz_tbl[] = {
>>>>       PLL_36XX_RATE(24 * MHZ, 600000000U, 100, 2, 1, 0),
>>>>       PLL_36XX_RATE(24 * MHZ, 400000000U, 200, 3, 2, 0),
>>>> @@ -1467,7 +1480,7 @@ static void __init exynos5x_clk_init(struct device_node *np,
>>>>               exynos5x_plls[apll].rate_table = exynos5420_pll2550x_24mhz_tbl;
>>>>               exynos5x_plls[epll].rate_table = exynos5420_epll_24mhz_tbl;
>>>>               exynos5x_plls[kpll].rate_table = exynos5420_pll2550x_24mhz_tbl;
>>>> -            exynos5x_plls[bpll].rate_table = exynos5420_pll2550x_24mhz_tbl;
>>>> +            exynos5x_plls[bpll].rate_table = exynos5422_bpll_rate_table;
>>>
>>> Exynos5422 used the same PLL table for apll, kpll, bpll and so on.
>>> You don't need to make the separate pll table. Just add new entries
>>> to exynos5420_pll2550x_24mhz_tbl table.
>> OK, I will extend the exynos5420_pll2550x_24mhz_tbl table.
>>
>> In v4 patch set, it will be fixed.
>>
>> Regards,
>> Lukasz
>>>
>>>>       }
>>>>
>>>>       samsung_clk_register_pll(ctx, exynos5x_plls, ARRAY_SIZE(exynos5x_plls),
>>>>
>>>
> 
> 
> 
> --
> Best Regards,
> Chanwoo Choi
> Samsung Electronics
> 
>