From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sowjanya Komatineni Subject: Re: [PATCH v8 14/21] clk: tegra210: Add suspend and resume support Date: Mon, 12 Aug 2019 10:28:20 -0700 Message-ID: <931b027d-fdf3-220b-167a-4177fa917781@nvidia.com> References: <1565308020-31952-1-git-send-email-skomatineni@nvidia.com> <1565308020-31952-15-git-send-email-skomatineni@nvidia.com> <7d101ec9-c559-8b40-1764-6bf67a9c7a7a@nvidia.com> <4397de5d-772d-2b04-5f87-b2988f6c96c8@gmail.com> <805a825e-f19d-d056-83eb-8ed1cb1c089c@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Dmitry Osipenko Cc: thierry.reding@gmail.com, jonathanh@nvidia.com, tglx@linutronix.de, jason@lakedaemon.net, marc.zyngier@arm.com, linus.walleij@linaro.org, stefan@agner.ch, mark.rutland@arm.com, pdeschrijver@nvidia.com, pgaikwad@nvidia.com, sboyd@kernel.org, linux-clk@vger.kernel.org, linux-gpio@vger.kernel.org, jckuo@nvidia.com, josephl@nvidia.com, talho@nvidia.com, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, mperttunen@nvidia.com, spatra@nvidia.com, robh+dt@kernel.org, devicetree@vger.kernel.org, rjw@rjwysocki.net, viresh.kumar@linaro.org, linux-pm@vger.kernel.org List-Id: devicetree@vger.kernel.org On 8/12/19 9:25 AM, Dmitry Osipenko wrote: > 11.08.2019 22:15, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >> On 8/11/19 10:39 AM, Dmitry Osipenko wrote: >>> 09.08.2019 21:40, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>>> On 8/9/19 11:18 AM, Dmitry Osipenko wrote: >>>>> 09.08.2019 19:19, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>>>>> On 8/9/19 6:56 AM, Dmitry Osipenko wrote: >>>>>>> 09.08.2019 2:46, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82= : >>>>>>>> This patch adds support for clk: tegra210: suspend-resume. >>>>>>>> >>>>>>>> All the CAR controller settings are lost on suspend when core >>>>>>>> power goes off. >>>>>>>> >>>>>>>> This patch has implementation for saving and restoring all PLLs >>>>>>>> and clocks context during system suspend and resume to have the >>>>>>>> clocks back to same state for normal operation. >>>>>>>> >>>>>>>> Clock driver suspend and resume are registered as syscore_ops as c= locks >>>>>>>> restore need to happen before the other drivers resume to have all= their >>>>>>>> clocks back to the same state as before suspend. >>>>>>>> >>>>>>>> Signed-off-by: Sowjanya Komatineni >>>>>>>> --- >>>>>>>> =C2=A0=C2=A0 drivers/clk/tegra/clk-tegra210.c | 103 +++++++++++++= ++++++++++++++++++++++++-- >>>>>>>> =C2=A0=C2=A0 drivers/clk/tegra/clk.c=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0 |=C2=A0 64 ++++++++++++++++++++++++ >>>>>>>> =C2=A0=C2=A0 drivers/clk/tegra/clk.h=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0 |=C2=A0=C2=A0 3 ++ >>>>>>>> =C2=A0=C2=A0 3 files changed, 166 insertions(+), 4 deletions(-) >>>>>>>> >>>>>>>> diff --git a/drivers/clk/tegra/clk-tegra210.c b/drivers/clk/tegra/= clk-tegra210.c >>>>>>>> index 998bf60b219a..8dd6f4f4debb 100644 >>>>>>>> --- a/drivers/clk/tegra/clk-tegra210.c >>>>>>>> +++ b/drivers/clk/tegra/clk-tegra210.c >>>>>>>> @@ -9,13 +9,13 @@ >>>>>>>> =C2=A0=C2=A0 #include >>>>>>>> =C2=A0=C2=A0 #include >>>>>>>> =C2=A0=C2=A0 #include >>>>>>>> +#include >>>>>>>> =C2=A0=C2=A0 #include >>>>>>>> =C2=A0=C2=A0 #include >>>>>>>> =C2=A0=C2=A0 #include >>>>>>>> =C2=A0=C2=A0 #include >>>>>>>> =C2=A0=C2=A0 #include >>>>>>>> =C2=A0=C2=A0 #include >>>>>>>> -#include >>>>>>>> =C2=A0=C2=A0 #include >>>>>>>> =C2=A0=C2=A0 #include >>>>>>>> =C2=A0=C2=A0 @@ -220,11 +220,15 @@ >>>>>>>> =C2=A0=C2=A0 #define CLK_M_DIVISOR_SHIFT 2 >>>>>>>> =C2=A0=C2=A0 #define CLK_M_DIVISOR_MASK 0x3 >>>>>>>> =C2=A0=C2=A0 +#define CLK_MASK_ARM=C2=A0=C2=A0=C2=A0 0x44 >>>>>>>> +#define MISC_CLK_ENB=C2=A0=C2=A0=C2=A0 0x48 >>>>>>>> + >>>>>>>> =C2=A0=C2=A0 #define RST_DFLL_DVCO 0x2f4 >>>>>>>> =C2=A0=C2=A0 #define DVFS_DFLL_RESET_SHIFT 0 >>>>>>>> =C2=A0=C2=A0 =C2=A0 #define CLK_RST_CONTROLLER_RST_DEV_Y_SET 0x2a= 8 >>>>>>>> =C2=A0=C2=A0 #define CLK_RST_CONTROLLER_RST_DEV_Y_CLR 0x2ac >>>>>>>> +#define CPU_SOFTRST_CTRL 0x380 >>>>>>>> =C2=A0=C2=A0 =C2=A0 #define LVL2_CLK_GATE_OVRA 0xf8 >>>>>>>> =C2=A0=C2=A0 #define LVL2_CLK_GATE_OVRC 0x3a0 >>>>>>>> @@ -2825,6 +2829,7 @@ static int tegra210_enable_pllu(void) >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 struct tegra_clk_pll_freq_ta= ble *fentry; >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 struct tegra_clk_pll pllu; >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 u32 reg; >>>>>>>> +=C2=A0=C2=A0=C2=A0 int ret; >>>>>>>> =C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 for (fentry =3D pll_u= _freq_table; fentry->input_rate; fentry++) { >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (= fentry->input_rate =3D=3D pll_ref_freq) >>>>>>>> @@ -2853,9 +2858,14 @@ static int tegra210_enable_pllu(void) >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 reg |=3D PLL_ENABLE; >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 writel(reg, clk_base + PLLU_= BASE); >>>>>>>> =C2=A0=C2=A0 -=C2=A0=C2=A0=C2=A0 readl_relaxed_poll_timeout_atomi= c(clk_base + PLLU_BASE, reg, >>>>>>>> -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 reg & PLL_B= ASE_LOCK, 2, 1000); >>>>>>>> -=C2=A0=C2=A0=C2=A0 if (!(reg & PLL_BASE_LOCK)) { >>>>>>>> +=C2=A0=C2=A0=C2=A0 /* >>>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0 * During clocks resume, same PLLU init a= nd enable sequence get >>>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0 * executed. So, readx_poll_timeout_atomi= c can't be used here as it >>>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0 * uses ktime_get() and timekeeping resum= e doesn't happen by that >>>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0 * time. So, using tegra210_wait_for_mask= for PLL LOCK. >>>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0 */ >>>>>>>> +=C2=A0=C2=A0=C2=A0 ret =3D tegra210_wait_for_mask(&pllu, PLLU_BAS= E, PLL_BASE_LOCK); >>>>>>>> +=C2=A0=C2=A0=C2=A0 if (ret) { >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 pr_e= rr("Timed out waiting for PLL_U to lock\n"); >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 retu= rn -ETIMEDOUT; >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 } >>>>>>>> @@ -3288,6 +3298,84 @@ static void tegra210_disable_cpu_clock(u32 = cpu) >>>>>>>> =C2=A0=C2=A0 } >>>>>>>> =C2=A0=C2=A0 =C2=A0 #ifdef CONFIG_PM_SLEEP >>>>>>>> +/* >>>>>>>> + * This array lists mask values for each peripheral clk bank >>>>>>>> + * to mask out reserved bits during the clocks state restore >>>>>>>> + * on SC7 resume to prevent accidental writes to these reserved >>>>>>>> + * bits. >>>>>>>> + */ >>>>>>>> +static u32 periph_clk_rsvd_mask[TEGRA210_CAR_BANK_COUNT] =3D { >>>>>>> Should be more natural to have a "valid_mask" instead of "rsvd_mask= ". >>>>>>> >>>>>>> What's actually wrong with touching of the reserved bits? They must= be NO-OP.. or the >>>>>>> reserved bits are actually some kind of "secret" bits? If those bit= s have some use-case >>>>>>> outside of Silicon HW (like FPGA simulation), then this doesn't mat= ter for upstream >>>>>>> and you >>>>>>> have to keep the workaround locally in the downstream kernel or wha= tever. >>>>>> Will rename as valid_mask. >>>>>> >>>>>> some bits in these registers are undefined and is not good to write = to these bits as they >>>>>> can cause pslverr. >>>>> Okay, it should be explained in the comment. >>>>> >>>>> Is it possible to disable trapping of changing the undefined bits? >>>> No its internal to design >>> Okay. >>> >>> Also, what about to move the valid_mask into struct tegra_clk_periph_re= gs? >> No, we cannot move to tegra_clk_periph_regs as its in tegra/clk.c and is= common for all tegra. >> >> Reserved bits are different on tegra chips so should come from Tegra chi= p specific clock >> driver like >> >> clk-tegra210 for Tegra210. > Could you please check whether the reserved bits are RAZ (read as zero)? > > [snip] yes all reserved bits of clk_enb register is 0. This should not be set to 1= . As I will be changing to variable name to valid_mask instead of reserved=20 mask, will also change values to valid mask so it can be used directly=20 to write to clk_enb for enabling all peripherals clks.