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From: Dmitry Osipenko <digetx@gmail.com>
To: Sowjanya Komatineni <skomatineni@nvidia.com>
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
Subject: Re: [PATCH v8 14/21] clk: tegra210: Add suspend and resume support
Date: Mon, 12 Aug 2019 21:19:32 +0300
Message-ID: <1779e92b-fa4d-68ab-9218-51970eee1ec5@gmail.com> (raw)
In-Reply-To: <931b027d-fdf3-220b-167a-4177fa917781@nvidia.com>

12.08.2019 20:28, Sowjanya Komatineni пишет:
> 
> On 8/12/19 9:25 AM, Dmitry Osipenko wrote:
>> 11.08.2019 22:15, Sowjanya Komatineni пишет:
>>> On 8/11/19 10:39 AM, Dmitry Osipenko wrote:
>>>> 09.08.2019 21:40, Sowjanya Komatineni пишет:
>>>>> On 8/9/19 11:18 AM, Dmitry Osipenko wrote:
>>>>>> 09.08.2019 19:19, Sowjanya Komatineni пишет:
>>>>>>> On 8/9/19 6:56 AM, Dmitry Osipenko wrote:
>>>>>>>> 09.08.2019 2:46, Sowjanya Komatineni пишет:
>>>>>>>>> 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 clocks
>>>>>>>>> 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 <skomatineni@nvidia.com>
>>>>>>>>> ---
>>>>>>>>>     drivers/clk/tegra/clk-tegra210.c | 103 +++++++++++++++++++++++++++++++++++++--
>>>>>>>>>     drivers/clk/tegra/clk.c          |  64 ++++++++++++++++++++++++
>>>>>>>>>     drivers/clk/tegra/clk.h          |   3 ++
>>>>>>>>>     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 @@
>>>>>>>>>     #include <linux/clkdev.h>
>>>>>>>>>     #include <linux/of.h>
>>>>>>>>>     #include <linux/of_address.h>
>>>>>>>>> +#include <linux/syscore_ops.h>
>>>>>>>>>     #include <linux/delay.h>
>>>>>>>>>     #include <linux/export.h>
>>>>>>>>>     #include <linux/mutex.h>
>>>>>>>>>     #include <linux/clk/tegra.h>
>>>>>>>>>     #include <dt-bindings/clock/tegra210-car.h>
>>>>>>>>>     #include <dt-bindings/reset/tegra210-car.h>
>>>>>>>>> -#include <linux/iopoll.h>
>>>>>>>>>     #include <linux/sizes.h>
>>>>>>>>>     #include <soc/tegra/pmc.h>
>>>>>>>>>     @@ -220,11 +220,15 @@
>>>>>>>>>     #define CLK_M_DIVISOR_SHIFT 2
>>>>>>>>>     #define CLK_M_DIVISOR_MASK 0x3
>>>>>>>>>     +#define CLK_MASK_ARM    0x44
>>>>>>>>> +#define MISC_CLK_ENB    0x48
>>>>>>>>> +
>>>>>>>>>     #define RST_DFLL_DVCO 0x2f4
>>>>>>>>>     #define DVFS_DFLL_RESET_SHIFT 0
>>>>>>>>>       #define CLK_RST_CONTROLLER_RST_DEV_Y_SET 0x2a8
>>>>>>>>>     #define CLK_RST_CONTROLLER_RST_DEV_Y_CLR 0x2ac
>>>>>>>>> +#define CPU_SOFTRST_CTRL 0x380
>>>>>>>>>       #define LVL2_CLK_GATE_OVRA 0xf8
>>>>>>>>>     #define LVL2_CLK_GATE_OVRC 0x3a0
>>>>>>>>> @@ -2825,6 +2829,7 @@ static int tegra210_enable_pllu(void)
>>>>>>>>>         struct tegra_clk_pll_freq_table *fentry;
>>>>>>>>>         struct tegra_clk_pll pllu;
>>>>>>>>>         u32 reg;
>>>>>>>>> +    int ret;
>>>>>>>>>           for (fentry = pll_u_freq_table; fentry->input_rate; fentry++) {
>>>>>>>>>             if (fentry->input_rate == pll_ref_freq)
>>>>>>>>> @@ -2853,9 +2858,14 @@ static int tegra210_enable_pllu(void)
>>>>>>>>>         reg |= PLL_ENABLE;
>>>>>>>>>         writel(reg, clk_base + PLLU_BASE);
>>>>>>>>>     -    readl_relaxed_poll_timeout_atomic(clk_base + PLLU_BASE, reg,
>>>>>>>>> -                      reg & PLL_BASE_LOCK, 2, 1000);
>>>>>>>>> -    if (!(reg & PLL_BASE_LOCK)) {
>>>>>>>>> +    /*
>>>>>>>>> +     * During clocks resume, same PLLU init and enable sequence get
>>>>>>>>> +     * executed. So, readx_poll_timeout_atomic can't be used here as it
>>>>>>>>> +     * uses ktime_get() and timekeeping resume doesn't happen by that
>>>>>>>>> +     * time. So, using tegra210_wait_for_mask for PLL LOCK.
>>>>>>>>> +     */
>>>>>>>>> +    ret = tegra210_wait_for_mask(&pllu, PLLU_BASE, PLL_BASE_LOCK);
>>>>>>>>> +    if (ret) {
>>>>>>>>>             pr_err("Timed out waiting for PLL_U to lock\n");
>>>>>>>>>             return -ETIMEDOUT;
>>>>>>>>>         }
>>>>>>>>> @@ -3288,6 +3298,84 @@ static void tegra210_disable_cpu_clock(u32 cpu)
>>>>>>>>>     }
>>>>>>>>>       #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] = {
>>>>>>>> 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 bits have some use-case
>>>>>>>> outside of Silicon HW (like FPGA simulation), then this doesn't matter for upstream
>>>>>>>> and you
>>>>>>>> have to keep the workaround locally in the downstream kernel or whatever.
>>>>>>> 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_regs?
>>> 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 chip 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 mask, will also
> change values to valid mask so it can be used directly to write to clk_enb for enabling all
> peripherals clks.
> 

It looks to me that the tegra_clk_periph_force_on() could be made local to the
clk-tegra210.c and then the raw clk_enb values could be written directly instead of having
the clk_enb[] array, probably that will be a bit cleaner.

  reply index

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-08 23:46 [PATCH v8 00/21] SC7 entry and exit support for Tegra210 Sowjanya Komatineni
2019-08-08 23:46 ` [PATCH v8 01/21] pinctrl: tegra: Fix write barrier placement in pmx_writel Sowjanya Komatineni
2019-08-09 11:38   ` Dmitry Osipenko
2019-08-12  9:20   ` Thierry Reding
2019-08-14  8:32   ` Linus Walleij
2019-08-08 23:46 ` [PATCH v8 02/21] pinctrl: tegra: Add write barrier after all pinctrl register writes Sowjanya Komatineni
2019-08-09 11:39   ` Dmitry Osipenko
2019-08-12  9:20   ` Thierry Reding
2019-08-14  8:33   ` Linus Walleij
2019-08-08 23:46 ` [PATCH v8 03/21] clk: tegra: divider: Save and restore divider rate Sowjanya Komatineni
2019-08-12  9:21   ` Thierry Reding
2019-08-08 23:46 ` [PATCH v8 04/21] clk: tegra: pllout: Save and restore pllout context Sowjanya Komatineni
2019-08-11 18:04   ` Dmitry Osipenko
2019-08-08 23:46 ` [PATCH v8 05/21] clk: tegra: pll: Save and restore pll context Sowjanya Komatineni
2019-08-09 11:33   ` Dmitry Osipenko
2019-08-09 17:39     ` Sowjanya Komatineni
2019-08-09 17:50       ` Dmitry Osipenko
2019-08-09 18:50         ` Sowjanya Komatineni
2019-08-11 17:24           ` Dmitry Osipenko
2019-08-09 12:46   ` Dmitry Osipenko
2019-08-08 23:46 ` [PATCH v8 06/21] clk: tegra: Support for OSC context save and restore Sowjanya Komatineni
2019-08-08 23:46 ` [PATCH v8 07/21] clk: Add API to get index of the clock parent Sowjanya Komatineni
2019-08-09 11:49   ` Dmitry Osipenko
2019-08-12  9:47   ` Thierry Reding
2019-08-08 23:46 ` [PATCH v8 08/21] clk: tegra: periph: Add restore_context support Sowjanya Komatineni
2019-08-09 11:55   ` Dmitry Osipenko
2019-08-09 12:20     ` Dmitry Osipenko
2019-08-09 16:55       ` Sowjanya Komatineni
2019-08-12  9:50   ` Thierry Reding
2019-08-08 23:46 ` [PATCH v8 09/21] clk: tegra: clk-super: Fix to enable PLLP branches to CPU Sowjanya Komatineni
2019-08-09 12:11   ` Dmitry Osipenko
2019-08-12  9:53   ` Thierry Reding
2019-08-08 23:46 ` [PATCH v8 10/21] clk: tegra: clk-super: Add restore-context support Sowjanya Komatineni
2019-08-09 12:17   ` Dmitry Osipenko
2019-08-09 17:08     ` Sowjanya Komatineni
2019-08-11 17:29       ` Dmitry Osipenko
2019-08-12  9:55   ` Thierry Reding
2019-08-08 23:46 ` [PATCH v8 11/21] clk: tegra: clk-dfll: Add suspend and resume support Sowjanya Komatineni
2019-08-09 12:23   ` Dmitry Osipenko
2019-08-09 16:39     ` Sowjanya Komatineni
2019-08-09 18:00       ` Dmitry Osipenko
2019-08-09 18:33         ` Sowjanya Komatineni
2019-08-09 18:52           ` Dmitry Osipenko
2019-08-12 10:01   ` Thierry Reding
2019-08-08 23:46 ` [PATCH v8 12/21] cpufreq: tegra124: " Sowjanya Komatineni
2019-08-12 10:07   ` Thierry Reding
2019-08-08 23:46 ` [PATCH v8 13/21] clk: tegra210: Use fence_udelay during PLLU init Sowjanya Komatineni
2019-08-11 18:02   ` Dmitry Osipenko
2019-08-11 19:16     ` Sowjanya Komatineni
2019-08-08 23:46 ` [PATCH v8 14/21] clk: tegra210: Add suspend and resume support Sowjanya Komatineni
2019-08-09 13:56   ` Dmitry Osipenko
2019-08-09 16:19     ` Sowjanya Komatineni
2019-08-09 18:18       ` Dmitry Osipenko
     [not found]         ` <cbe94f84-a17b-7e1a-811d-89db571784e1@nvidia.com>
2019-08-11 17:39           ` Dmitry Osipenko
2019-08-11 19:15             ` Sowjanya Komatineni
2019-08-12 16:25               ` Dmitry Osipenko
2019-08-12 17:28                 ` Sowjanya Komatineni
2019-08-12 18:19                   ` Dmitry Osipenko [this message]
2019-08-12 19:03                     ` Sowjanya Komatineni
2019-08-12 20:28                       ` Dmitry Osipenko
2019-08-12 10:17   ` Thierry Reding
2019-08-08 23:46 ` [PATCH v8 15/21] soc/tegra: pmc: Allow to support more tegras wake Sowjanya Komatineni
2019-08-11 17:52   ` Dmitry Osipenko
2019-08-08 23:46 ` [PATCH v8 16/21] soc/tegra: pmc: Add pmc wake support for tegra210 Sowjanya Komatineni
2019-08-09 13:28   ` Dmitry Osipenko
2019-08-08 23:46 ` [PATCH v8 17/21] arm64: tegra: Enable wake from deep sleep on RTC alarm Sowjanya Komatineni
2019-08-08 23:46 ` [PATCH v8 18/21] soc/tegra: pmc: Configure core power request polarity Sowjanya Komatineni
2019-08-09 13:13   ` Dmitry Osipenko
2019-08-08 23:46 ` [PATCH v8 19/21] soc/tegra: pmc: Configure deep sleep control settings Sowjanya Komatineni
2019-08-09 13:23   ` Dmitry Osipenko
2019-08-09 16:23     ` Sowjanya Komatineni
2019-08-09 17:24       ` Sowjanya Komatineni
2019-08-09 18:22         ` Dmitry Osipenko
2019-08-08 23:46 ` [PATCH v8 20/21] arm64: dts: tegra210-p2180: Jetson TX1 SC7 timings Sowjanya Komatineni
2019-08-08 23:47 ` [PATCH v8 21/21] arm64: dts: tegra210-p3450: Jetson Nano " Sowjanya Komatineni

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