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Subject: Re: [PATCH v4 2/8] clk: samsung: add new clocks for DMC for
 Exynos5422 SoC
To:     cwchoi00@gmail.com
Cc:     devicetree <devicetree@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Linux PM list <linux-pm@vger.kernel.org>,
        linux-samsung-soc <linux-samsung-soc@vger.kernel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Kukjin Kim <kgene@kernel.org>,
        Chanwoo Choi <cw00.choi@samsung.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Sylwester Nawrocki <s.nawrocki@samsung.com>,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>, linux-clk@vger.kernel.org,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
From:   Lukasz Luba <l.luba@partner.samsung.com>
Message-ID: <ae5a3ed8-a075-5ee4-e50a-dc4d2a9c5485@partner.samsung.com>
Date:   Mon, 11 Feb 2019 12:11:47 +0100
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References: <CGME20190201164719eucas1p2091c6d41a6cc21a3d36081daf4bc8267@eucas1p2.samsung.com>
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Hi Chanwoo,

On 2/3/19 10:56 AM, Chanwoo Choi wrote:
> Hi Lukasz,
> 
> I recommend that please don't send the version up patchset before
> finishing the discussion.
> 
> 2019년 2월 2일 (토) 오전 2:47, Lukasz Luba <l.luba@partner.samsung.com>님이 작성:
>>
>> This patch provides support for clocks needed for Dynamic Memory Controller
>> in Exynos5422 SoC. It adds CDREX base register addresses, new DIV, MUX and
>> GATE entries.
>>
>> Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
>> ---
>>   drivers/clk/samsung/clk-exynos5420.c | 46 ++++++++++++++++++++++++++++++++----
>>   1 file changed, 42 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/clk/samsung/clk-exynos5420.c b/drivers/clk/samsung/clk-exynos5420.c
>> index 34cce3c..f1a4f56 100644
>> --- a/drivers/clk/samsung/clk-exynos5420.c
>> +++ b/drivers/clk/samsung/clk-exynos5420.c
>> @@ -132,6 +132,8 @@
>>   #define BPLL_LOCK              0x20010
>>   #define BPLL_CON0              0x20110
>>   #define SRC_CDREX              0x20200
>> +#define GATE_BUS_CDREX0                0x20700
>> +#define GATE_BUS_CDREX1                0x20704
>>   #define DIV_CDREX0             0x20500
>>   #define DIV_CDREX1             0x20504
>>   #define KPLL_LOCK              0x28000
>> @@ -248,6 +250,8 @@ static const unsigned long exynos5x_clk_regs[] __initconst = {
>>          DIV_CDREX1,
>>          SRC_KFC,
>>          DIV_KFC0,
>> +       GATE_BUS_CDREX0,
>> +       GATE_BUS_CDREX1,
>>   };
>>
>>   static const unsigned long exynos5800_clk_regs[] __initconst = {
>> @@ -425,6 +429,10 @@ PNAME(mout_group13_5800_p) = { "dout_osc_div", "mout_sw_aclkfl1_550_cam" };
>>   PNAME(mout_group14_5800_p)     = { "dout_aclk550_cam", "dout_sclk_sw" };
>>   PNAME(mout_group15_5800_p)     = { "dout_osc_div", "mout_sw_aclk550_cam" };
>>   PNAME(mout_group16_5800_p)     = { "dout_osc_div", "mout_mau_epll_clk" };
>> +PNAME(mout_mx_mspll_ccore_phy_p) = { "sclk_bpll", "mout_sclk_dpll",
>> +                                       "mout_sclk_mpll", "ff_dout_spll2",
>> +                                       "mout_sclk_spll", "mout_sclk_epll"};
>> +
> 
> Remove unneeded extra blank line.
OK
> 
>>
>>   /* fixed rate clocks generated outside the soc */
>>   static struct samsung_fixed_rate_clock
>> @@ -450,7 +458,7 @@ static const struct samsung_fixed_factor_clock
>>   static const struct samsung_fixed_factor_clock
>>                  exynos5800_fixed_factor_clks[] __initconst = {
>>          FFACTOR(0, "ff_dout_epll2", "mout_sclk_epll", 1, 2, 0),
>> -       FFACTOR(0, "ff_dout_spll2", "mout_sclk_spll", 1, 2, 0),
>> +       FFACTOR(CLK_FF_DOUT_SPLL2, "ff_dout_spll2", "mout_sclk_spll", 1, 2, 0),
>>   };
>>
>>   static const struct samsung_mux_clock exynos5800_mux_clks[] __initconst = {
>> @@ -472,11 +480,14 @@ static const struct samsung_mux_clock exynos5800_mux_clks[] __initconst = {
>>          MUX(0, "mout_aclk300_disp1", mout_group5_5800_p, SRC_TOP2, 24, 2),
>>          MUX(0, "mout_aclk300_gscl", mout_group5_5800_p, SRC_TOP2, 28, 2),
>>
>> +       MUX(CLK_MOUT_MX_MSPLL_CCORE_PHY, "mout_mx_mspll_ccore_phy",
>> +               mout_mx_mspll_ccore_phy_p, SRC_TOP7, 0, 3),
>> +
>>          MUX(CLK_MOUT_MX_MSPLL_CCORE, "mout_mx_mspll_ccore",
>> -                       mout_mx_mspll_ccore_p, SRC_TOP7, 16, 2),
>> +                       mout_mx_mspll_ccore_p, SRC_TOP7, 16, 3),
>>          MUX_F(CLK_MOUT_MAU_EPLL, "mout_mau_epll_clk", mout_mau_epll_clk_5800_p,
>>                          SRC_TOP7, 20, 2, CLK_SET_RATE_PARENT, 0),
>> -       MUX(0, "sclk_bpll", mout_bpll_p, SRC_TOP7, 24, 1),
>> +       MUX(CLK_SCLK_BPLL, "sclk_bpll", mout_bpll_p, SRC_TOP7, 24, 1),
>>          MUX(0, "mout_epll2", mout_epll2_5800_p, SRC_TOP7, 28, 1),
>>
>>          MUX(0, "mout_aclk550_cam", mout_group3_5800_p, SRC_TOP8, 16, 3),
>> @@ -648,7 +659,7 @@ static const struct samsung_mux_clock exynos5x_mux_clks[] __initconst = {
> 
> The newly added clocks by this patch are supported on all Exynos5420/5422/5800?
The clocks are the same for Exynos5420/5422/5800 DMCs.

> I'm not sure because on the patch description, you only mentioned the
> Exynos5422 without Exynos5420/Exynos5800.
The driver code supports currently only Exynos5422 due to specific
timings inside, but the clocks are for all three Exynos SoCs.
It does not harm the Exynos5420/5800.
> 
> As for now, I can't check the Exynos TRM because I'm in holiday until
> next Wednesday. I will check them with Exynos542-/5422/5800 TRM on
> next Thursday.
OK, please add me to the communication thread with them. We will speed
up the process (I can test something for them if needed).
> 
>>
>>          MUX(0, "mout_sclk_mpll", mout_mpll_p, SRC_TOP6, 0, 1),
>>          MUX(CLK_MOUT_VPLL, "mout_sclk_vpll", mout_vpll_p, SRC_TOP6, 4, 1),
>> -       MUX(0, "mout_sclk_spll", mout_spll_p, SRC_TOP6, 8, 1),
>> +       MUX(CLK_MOUT_SCLK_SPLL, "mout_sclk_spll", mout_spll_p, SRC_TOP6, 8, 1),
>>          MUX(0, "mout_sclk_ipll", mout_ipll_p, SRC_TOP6, 12, 1),
>>          MUX(0, "mout_sclk_rpll", mout_rpll_p, SRC_TOP6, 16, 1),
>>          MUX_F(CLK_MOUT_EPLL, "mout_sclk_epll", mout_epll_p, SRC_TOP6, 20, 1,
>> @@ -817,6 +828,8 @@ static const struct samsung_div_clock exynos5x_div_clks[] __initconst = {
>>          DIV(CLK_DOUT_CLK2X_PHY0, "dout_clk2x_phy0", "dout_sclk_cdrex",
>>                          DIV_CDREX0, 3, 5),
>>
>> +       DIV(0, "dout_pclk_drex0", "dout_cclk_drex0", DIV_CDREX0, 28, 3),
> 
> Before applied this patch, on line 809, DIV_CDREX0[28:30] was already
> defined with "dout_pclk_cdrex" gate clock name.
In my previous email, I have mentioned that the same bits
(8 combinations) are controlling 3 dividers, which re-branch to 3 edges
in the clock tree named:
CLKDIV_PCLK_CDREX, CLKDIV_PCLK_DREX0, CLKDIV_PCLK_DREX1.
It is in the Exynos5422_UM_REV0.10 documentation section:
7.9.6.7 CLK_DIV_CDREX0

They are put into one because there is a need of synchronization between
the BUS and DREXs (two external memory interfaces).
That's why it looks good in the clock information summary when an
SW engineer can see these HW assumptions.

If you disagree and would like to see only minimal clock definition
which makes the HW working, please write it on LKML.
The clock summary would not be reflecting the actual hierarchy and
someone who is looking for a specific clock details will not find it.

  Why do you redefine it
> with same register/same bit with the different clock name?
The clock is added for information purpose. I can remove it if you like,
but then the clock summary would not reflect the actual HW implementation.

> driver have to get only unique clock for the same register/same bit
> information.
True, driver gets the clocks which have exported IDs.
This one has '0' as you can see and is only for the clk_summary
information output.


The purpose of the patch with detailed clock tree related to DMC was
information, not the driver usage. That's why some clocks they did
no have IDs so drivers would not take them (without a hack).

> 
>     808         /* CDREX Block */
>     809         DIV(CLK_DOUT_PCLK_CDREX, "dout_pclk_cdrex",
> "dout_aclk_cdrex1",
>     810                         DIV_CDREX0, 28, 3),
> 
> And also, you don't use "dout_pclk_drex0" defined by you for
> CLK_ACLK_PPMU_DREX* gate clock on below. Instead, you use the already
> defined 'dout_pclk_cdrex' as I commented.
True
> 
>> +
>>          DIV(CLK_DOUT_PCLK_CORE_MEM, "dout_pclk_core_mem", "mout_mclk_cdrex",
>>                          DIV_CDREX1, 8, 3),
>>
>> @@ -1170,6 +1183,31 @@ static const struct samsung_gate_clock exynos5x_gate_clks[] __initconst = {
>>                          GATE_TOP_SCLK_ISP, 12, CLK_SET_RATE_PARENT, 0),
>>
>>          GATE(CLK_G3D, "g3d", "mout_user_aclk_g3d", GATE_IP_G3D, 9, 0, 0),
>> +
> 
> Add the following comment for the readability in order to sustain the
> consistency of this driver.
> /* CDREX Block */ or /* CDREX */
OK
> 
>> +       GATE(CLK_CLKM_PHY0, "clkm_phy0", "dout_sclk_cdrex",
>> +                       GATE_BUS_CDREX0, 0, 0, 0),
>> +       GATE(CLK_CLKM_PHY1, "clkm_phy1", "dout_sclk_cdrex",
>> +                       GATE_BUS_CDREX0, 1, 0, 0),
>> +       GATE(0, "mx_mspll_ccore_phy", "mout_mx_mspll_ccore_phy",
>> +                       SRC_MASK_TOP7, 0, CLK_IGNORE_UNUSED, 0),
>> +
>> +       GATE(CLK_ACLK_PPMU_DREX0_0, "aclk_ppmu_drex0_0", "dout_aclk_cdrex1",
>> +                       GATE_BUS_CDREX1, 15, CLK_IGNORE_UNUSED, 0),
>> +       GATE(CLK_ACLK_PPMU_DREX0_1, "aclk_ppmu_drex0_1", "dout_aclk_cdrex1",
>> +                       GATE_BUS_CDREX1, 14, CLK_IGNORE_UNUSED, 0),
>> +       GATE(CLK_ACLK_PPMU_DREX1_0, "aclk_ppmu_drex1_0", "dout_aclk_cdrex1",
>> +                       GATE_BUS_CDREX1, 13, CLK_IGNORE_UNUSED, 0),
>> +       GATE(CLK_ACLK_PPMU_DREX1_1, "aclk_ppmu_drex1_1", "dout_aclk_cdrex1",
>> +                       GATE_BUS_CDREX1, 12, CLK_IGNORE_UNUSED, 0),
> 
> You better to move the gate clock of GATE_BUS_CDREX[15:12] under the
> gate clock of GATE_BUS_CDREX[29:26]
> for the decending order because you defined them as the decending order.
Make sense, I will change it.

Regards,
Lukasz
> 
>> +
>> +       GATE(CLK_PCLK_PPMU_DREX0_0, "pclk_ppmu_drex0_0", "dout_pclk_cdrex",
>> +                       GATE_BUS_CDREX1, 29, CLK_IGNORE_UNUSED, 0),
>> +       GATE(CLK_PCLK_PPMU_DREX0_1, "pclk_ppmu_drex0_1", "dout_pclk_cdrex",
>> +                       GATE_BUS_CDREX1, 28, CLK_IGNORE_UNUSED, 0),
>> +       GATE(CLK_PCLK_PPMU_DREX1_0, "pclk_ppmu_drex1_0", "dout_pclk_cdrex",
>> +                       GATE_BUS_CDREX1, 27, CLK_IGNORE_UNUSED, 0),
>> +       GATE(CLK_PCLK_PPMU_DREX1_1, "pclk_ppmu_drex1_1", "dout_pclk_cdrex",
>> +                       GATE_BUS_CDREX1, 26, CLK_IGNORE_UNUSED, 0),
>>   };
>>
>>   static const struct samsung_div_clock exynos5x_disp_div_clks[] __initconst = {
>> --
>> 2.7.4
>>
> 
> 
> --
> Best Regards,
> Chanwoo Choi
> 
>