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Message-ID: <e2d0e8cc-b4ea-1148-4af1-fee6bb266cca@nvidia.com>
Date: Sun, 21 Jul 2019 23:52:30 -0700
From: Sowjanya Komatineni <skomatineni@...dia.com>
To: Dmitry Osipenko <digetx@...il.com>, <thierry.reding@...il.com>,
<jonathanh@...dia.com>, <tglx@...utronix.de>,
<jason@...edaemon.net>, <marc.zyngier@....com>,
<linus.walleij@...aro.org>, <stefan@...er.ch>,
<mark.rutland@....com>
CC: <pdeschrijver@...dia.com>, <pgaikwad@...dia.com>,
<sboyd@...nel.org>, <linux-clk@...r.kernel.org>,
<linux-gpio@...r.kernel.org>, <jckuo@...dia.com>,
<josephl@...dia.com>, <talho@...dia.com>,
<linux-tegra@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<mperttunen@...dia.com>, <spatra@...dia.com>, <robh+dt@...nel.org>,
<devicetree@...r.kernel.org>
Subject: Re: [PATCH V6 14/21] clk: tegra210: Add suspend and resume support
On 7/21/19 11:10 PM, Dmitry Osipenko wrote:
> 22.07.2019 1:45, Sowjanya Komatineni пишет:
>> On 7/21/19 2:38 PM, Dmitry Osipenko wrote:
>>> 21.07.2019 22:40, 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.
>>>>
>>>> Acked-by: Thierry Reding <treding@...dia.com>
>>>> Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.com>
>>>> ---
>>>> drivers/clk/tegra/clk-tegra210.c | 68
>>>> ++++++++++++++++++++++++++++++++++++++--
>>>> drivers/clk/tegra/clk.c | 14 +++++++++
>>>> drivers/clk/tegra/clk.h | 1 +
>>>> 3 files changed, 80 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/clk/tegra/clk-tegra210.c
>>>> b/drivers/clk/tegra/clk-tegra210.c
>>>> index 55a88c0824a5..68271873acc1 100644
>>>> --- a/drivers/clk/tegra/clk-tegra210.c
>>>> +++ b/drivers/clk/tegra/clk-tegra210.c
>>>> @@ -9,6 +9,7 @@
>>>> #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>
>>>> @@ -220,11 +221,15 @@
>>>> #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 +2830,7 @@ 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 +2859,8 @@ 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)) {
>>>> + ret = tegra210_wait_for_mask(&pllu, PLLU_BASE, PLL_BASE_LOCK);
>>>> + if (ret) {
>>> Why this is needed? Was there a bug?
>>>
>> during resume pllu init is needed and to use same terga210_init_pllu,
>> poll_timeout_atomic can't be used as its ony for atomic context.
>>
>> So changed to use wait_for_mask which should work in both cases.
> Atomic variant could be used from any context, not sure what do you
> mean. The 'atomic' part only means that function won't cause scheduling
> and that's it.
Sorry, replied incorrect. readx_poll_timeout_atomic uses ktime_get() and
during resume timekeeping suspend/resume happens later than clock
suspend/resume. So using tegra210_wait_for_mask.
both timekeeping and clk-tegra210 drivers are registered as syscore but
not ordered.
>>>> pr_err("Timed out waiting for PLL_U to lock\n");
>>>> return -ETIMEDOUT;
>>>> }
>>>> @@ -3288,6 +3293,56 @@ static void tegra210_disable_cpu_clock(u32 cpu)
>>>> }
>>>> #ifdef CONFIG_PM_SLEEP
>>>> +#define car_readl(_base, _off) readl_relaxed(clk_base + (_base) +
>>>> ((_off) * 4))
>>>> +#define car_writel(_val, _base, _off) \
>>>> + writel_relaxed(_val, clk_base + (_base) + ((_off) * 4))
>>>> +
>>>> +static u32 spare_reg_ctx, misc_clk_enb_ctx, clk_msk_arm_ctx;
>>>> +static u32 cpu_softrst_ctx[3];
>>>> +
>>>> +static int tegra210_clk_suspend(void)
>>>> +{
>>>> + unsigned int i;
>>>> +
>>>> + clk_save_context();
>>>> +
>>>> + /*
>>>> + * save the bootloader configured clock registers SPARE_REG0,
>>>> + * MISC_CLK_ENB, CLK_MASK_ARM, CPU_SOFTRST_CTRL
>>> Nit: Start all multi-line comments with a capital letter and put dot in
>>> the end of sentence.
>>>
>>>> + */
>>>> + spare_reg_ctx = readl_relaxed(clk_base + SPARE_REG0);
>>>> + misc_clk_enb_ctx = readl_relaxed(clk_base + MISC_CLK_ENB);
>>>> + clk_msk_arm_ctx = readl_relaxed(clk_base + CLK_MASK_ARM);
>>>> +
>>>> + for (i = 0; i < ARRAY_SIZE(cpu_softrst_ctx); i++)
>>>> + cpu_softrst_ctx[i] = car_readl(CPU_SOFTRST_CTRL, i);
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static void tegra210_clk_resume(void)
>>>> +{
>>>> + unsigned int i;
>>>> +
>>>> + tegra_clk_osc_resume(clk_base);
>>>> +
>>>> + /*
>>>> + * restore the bootloader configured clock registers SPARE_REG0,
>>>> + * MISC_CLK_ENB, CLK_MASK_ARM, CPU_SOFTRST_CTRL from saved context.
>>> Same here.
>>>
>>>> + */
>>>> + writel_relaxed(spare_reg_ctx, clk_base + SPARE_REG0);
>>>> + writel_relaxed(misc_clk_enb_ctx, clk_base + MISC_CLK_ENB);
>>>> + writel_relaxed(clk_msk_arm_ctx, clk_base + CLK_MASK_ARM);
>>>> +
>>>> + for (i = 0; i < ARRAY_SIZE(cpu_softrst_ctx); i++)
>>>> + car_writel(cpu_softrst_ctx[i], CPU_SOFTRST_CTRL, i);
>>>> +
>>>> + fence_udelay(5, clk_base);
>>>> +
>>>> + tegra210_init_pllu();
>>>> + clk_restore_context();
>>>> +}
>>>> +
>>>> static void tegra210_cpu_clock_suspend(void)
>>>> {
>>>> /* switch coresite to clk_m, save off original source */
>>>> @@ -3303,6 +3358,11 @@ static void tegra210_cpu_clock_resume(void)
>>>> }
>>>> #endif
>>>> +static struct syscore_ops tegra_clk_syscore_ops = {
>>>> + .suspend = tegra210_clk_suspend,
>>>> + .resume = tegra210_clk_resume,
>>>> +};
>>>> +
>>>> static struct tegra_cpu_car_ops tegra210_cpu_car_ops = {
>>>> .wait_for_reset = tegra210_wait_cpu_in_reset,
>>>> .disable_clock = tegra210_disable_cpu_clock,
>>>> @@ -3587,5 +3647,7 @@ static void __init tegra210_clock_init(struct
>>>> device_node *np)
>>>> tegra210_mbist_clk_init();
>>>> tegra_cpu_car_ops = &tegra210_cpu_car_ops;
>>>> +
>>>> + register_syscore_ops(&tegra_clk_syscore_ops);
>>>> }
>>>> CLK_OF_DECLARE(tegra210, "nvidia,tegra210-car", tegra210_clock_init);
>>>> diff --git a/drivers/clk/tegra/clk.c b/drivers/clk/tegra/clk.c
>>>> index 573e3c967ae1..eb08047fd02f 100644
>>>> --- a/drivers/clk/tegra/clk.c
>>>> +++ b/drivers/clk/tegra/clk.c
>>>> @@ -23,6 +23,7 @@
>>>> #define CLK_OUT_ENB_W 0x364
>>>> #define CLK_OUT_ENB_X 0x280
>>>> #define CLK_OUT_ENB_Y 0x298
>>>> +#define CLK_ENB_PLLP_OUT_CPU BIT(31)
>>>> #define CLK_OUT_ENB_SET_L 0x320
>>>> #define CLK_OUT_ENB_CLR_L 0x324
>>>> #define CLK_OUT_ENB_SET_H 0x328
>>>> @@ -199,6 +200,19 @@ const struct tegra_clk_periph_regs
>>>> *get_reg_bank(int clkid)
>>>> }
>>>> }
>>>> +void tegra_clk_set_pllp_out_cpu(bool enable)
>>>> +{
>>>> + u32 val;
>>>> +
>>>> + val = readl_relaxed(clk_base + CLK_OUT_ENB_Y);
>>>> + if (enable)
>>>> + val |= CLK_ENB_PLLP_OUT_CPU;
>>>> + else
>>>> + val &= ~CLK_ENB_PLLP_OUT_CPU;
>>>> +
>>>> + writel_relaxed(val, clk_base + CLK_OUT_ENB_Y);
>>>> +}
>>>> +
>>>> struct clk ** __init tegra_clk_init(void __iomem *regs, int num,
>>>> int banks)
>>>> {
>>>> clk_base = regs;
>>>> diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h
>>>> index 562a3ee2d537..0ffa763c755b 100644
>>>> --- a/drivers/clk/tegra/clk.h
>>>> +++ b/drivers/clk/tegra/clk.h
>>>> @@ -863,6 +863,7 @@ int div_frac_get(unsigned long rate, unsigned
>>>> parent_rate, u8 width,
>>>> u8 frac_width, u8 flags);
>>>> void tegra_clk_sync_state_pll(struct clk_hw *hw);
>>>> void tegra_clk_osc_resume(void __iomem *clk_base);
>>>> +void tegra_clk_set_pllp_out_cpu(bool enable);
>>>> /* Combined read fence with delay */
>>>> #define fence_udelay(delay, reg) \
>>>>
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