Date:   Wed, 18 Dec 2019 09:00:15 -0800
From:   Sowjanya Komatineni <skomatineni@...dia.com>
To:     Dmitry Osipenko <digetx@...il.com>, <thierry.reding@...il.com>,
        <jonathanh@...dia.com>, <mperttunen@...dia.com>,
        <gregkh@...uxfoundation.org>, <sboyd@...nel.org>,
        <robh+dt@...nel.org>, <mark.rutland@....com>
CC:     <pdeschrijver@...dia.com>, <pgaikwad@...dia.com>,
        <spujar@...dia.com>, <josephl@...dia.com>,
        <daniel.lezcano@...aro.org>, <mmaddireddy@...dia.com>,
        <markz@...dia.com>, <devicetree@...r.kernel.org>,
        <linux-clk@...r.kernel.org>, <linux-tegra@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 06/19] soc: tegra: Add Tegra PMC clock registrations
 into PMC driver


On 12/18/19 8:52 AM, Dmitry Osipenko wrote:
> 18.12.2019 18:50, Sowjanya Komatineni пишет:
>> On 12/18/19 7:46 AM, Sowjanya Komatineni wrote:
>>> On 12/18/19 12:35 AM, Dmitry Osipenko wrote:
>>>> 18.12.2019 11:30, Dmitry Osipenko пишет:
>>>>> 17.12.2019 23:03, Sowjanya Komatineni пишет:
>>>>>> Tegra PMC has clk_out_1, clk_out_2, and clk_out_3 clocks and currently
>>>>>> these PMC clocks are registered by Tegra clock driver with each
>>>>>> clock as
>>>>>> separate mux and gate clocks using clk_register_mux and
>>>>>> clk_register_gate
>>>>>> by passing PMC base address and register offsets and PMC
>>>>>> programming for
>>>>>> these clocks happens through direct PMC access by the clock driver.
>>>>>>
>>>>>> With this, when PMC is in secure mode any direct PMC access from the
>>>>>> non-secure world does not go through and these clocks will not be
>>>>>> functional.
>>>>>>
>>>>>> This patch adds these PMC clocks registration to pmc driver with
>>>>>> PMC as
>>>>>> a clock provider and registers each clock as single clock.
>>>>>>
>>>>>> clk_ops callback implementations for these clocks uses
>>>>>> tegra_pmc_readl and
>>>>>> tegra_pmc_writel which supports PMC programming in both secure mode
>>>>>> and
>>>>>> non-secure mode.
>>>>>>
>>>>>> Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.com>
>>>>>> ---
>>>>>>    drivers/soc/tegra/pmc.c | 248
>>>>>> ++++++++++++++++++++++++++++++++++++++++++++++++
>>>>>>    1 file changed, 248 insertions(+)
>>>>>>
>>>>>> diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
>>>>>> index ea0e11a09c12..6d65194a6e71 100644
>>>>>> --- a/drivers/soc/tegra/pmc.c
>>>>>> +++ b/drivers/soc/tegra/pmc.c
>>>>>> @@ -13,6 +13,9 @@
>>>>>>      #include <linux/arm-smccc.h>
>>>>>>    #include <linux/clk.h>
>>>>>> +#include <linux/clk-provider.h>
>>>>>> +#include <linux/clkdev.h>
>>>>>> +#include <linux/clk/clk-conf.h>
>>>>>>    #include <linux/clk/tegra.h>
>>>>>>    #include <linux/debugfs.h>
>>>>>>    #include <linux/delay.h>
>>>>>> @@ -48,6 +51,7 @@
>>>>>>    #include <dt-bindings/pinctrl/pinctrl-tegra-io-pad.h>
>>>>>>    #include <dt-bindings/gpio/tegra186-gpio.h>
>>>>>>    #include <dt-bindings/gpio/tegra194-gpio.h>
>>>>>> +#include <dt-bindings/soc/tegra-pmc.h>
>>>>>>      #define PMC_CNTRL            0x0
>>>>>>    #define  PMC_CNTRL_INTR_POLARITY    BIT(17) /* inverts INTR
>>>>>> polarity */
>>>>>> @@ -100,6 +104,7 @@
>>>>>>    #define PMC_WAKE2_STATUS        0x168
>>>>>>    #define PMC_SW_WAKE2_STATUS        0x16c
>>>>>>    +#define PMC_CLK_OUT_CNTRL        0x1a8
>>>>>>    #define PMC_SENSOR_CTRL            0x1b0
>>>>>>    #define  PMC_SENSOR_CTRL_SCRATCH_WRITE    BIT(2)
>>>>>>    #define  PMC_SENSOR_CTRL_ENABLE_RST    BIT(1)
>>>>>> @@ -155,6 +160,64 @@
>>>>>>    #define  TEGRA_SMC_PMC_READ    0xaa
>>>>>>    #define  TEGRA_SMC_PMC_WRITE    0xbb
>>>>>>    +struct pmc_clk {
>>>>>> +    struct clk_hw    hw;
>>>>>> +    unsigned long    offs;
>>>>>> +    u32        mux_mask;
>>>>>> +    u32        mux_shift;
>>>>>> +    u32        gate_shift;
>>>>>> +};
>>>>>> +
>>>>>> +#define to_pmc_clk(_hw) container_of(_hw, struct pmc_clk, hw)
>>>>>> +
>>>>>> +struct pmc_clk_init_data {
>>>>>> +    char *name;
>>>>>> +    const char *const *parents;
>>>>>> +    int num_parents;
>>>>>> +    int clk_id;
>>>>>> +    u8 mux_shift;
>>>>>> +    u8 gate_shift;
>>>>>> +};
>>>>>> +
>>>>>> +static const char * const clk_out1_parents[] = { "osc", "osc_div2",
>>>>>> +    "osc_div4", "extern1",
>>>>>> +};
>>>>>> +
>>>>>> +static const char * const clk_out2_parents[] = { "osc", "osc_div2",
>>>>>> +    "osc_div4", "extern2",
>>>>>> +};
>>>>>> +
>>>>>> +static const char * const clk_out3_parents[] = { "osc", "osc_div2",
>>>>>> +    "osc_div4", "extern3",
>>>>>> +};
>>>>>> +
>>>>>> +static const struct pmc_clk_init_data tegra_pmc_clks_data[] = {
>>>>>> +    {
>>>>>> +        .name = "clk_out_1",
>>>>>> +        .parents = clk_out1_parents,
>>>>>> +        .num_parents = ARRAY_SIZE(clk_out1_parents),
>>>>>> +        .clk_id = TEGRA_PMC_CLK_OUT_1,
>>>>>> +        .mux_shift = 6,
>>>>>> +        .gate_shift = 2,
>>>>> I'd replace these with a single .shift, given that mux_shift =
>>>>> gate_shift + 4 for all clocks.
>>>>>
>>>>>> +    },
>>>>>> +    {
>>>>>> +        .name = "clk_out_2",
>>>>>> +        .parents = clk_out2_parents,
>>>>>> +        .num_parents = ARRAY_SIZE(clk_out2_parents),
>>>>>> +        .clk_id = TEGRA_PMC_CLK_OUT_2,
>>>>>> +        .mux_shift = 14,
>>>>>> +        .gate_shift = 10,
>>>>>> +    },
>>>>>> +    {
>>>>>> +        .name = "clk_out_3",
>>>>>> +        .parents = clk_out3_parents,
>>>>>> +        .num_parents = ARRAY_SIZE(clk_out3_parents),
>>>>>> +        .clk_id = TEGRA_PMC_CLK_OUT_3,
>>>>>> +        .mux_shift = 22,
>>>>>> +        .gate_shift = 18,
>>>>>> +    },
>>>>>> +};
>>>>>> +
>>>>>>    struct tegra_powergate {
>>>>>>        struct generic_pm_domain genpd;
>>>>>>        struct tegra_pmc *pmc;
>>>>>> @@ -254,6 +317,9 @@ struct tegra_pmc_soc {
>>>>>>         */
>>>>>>        const struct tegra_wake_event *wake_events;
>>>>>>        unsigned int num_wake_events;
>>>>>> +
>>>>>> +    const struct pmc_clk_init_data *pmc_clks_data;
>>>>>> +    unsigned int num_pmc_clks;
>>>>>>    };
>>>>>>      static const char * const tegra186_reset_sources[] = {
>>>>>> @@ -2163,6 +2229,173 @@ static int tegra_pmc_clk_notify_cb(struct
>>>>>> notifier_block *nb,
>>>>>>        return NOTIFY_OK;
>>>>>>    }
>>>>>>    +static void pmc_clk_fence_udelay(u32 offset)
>>>>>> +{
>>>>>> +    tegra_pmc_readl(pmc, offset);
>>>>>> +    /* pmc clk propagation delay 2 us */
>>>>>> +    udelay(2);
>>>>>> +}
>>>>>> +
>>>>>> +static u8 pmc_clk_mux_get_parent(struct clk_hw *hw)
>>>>>> +{
>>>>>> +    struct pmc_clk *clk = to_pmc_clk(hw);
>>>>>> +    u32 val;
>>>>>> +
>>>>>> +    val = tegra_pmc_readl(pmc, clk->offs) >> clk->mux_shift;
>>>>>> +    val &= clk->mux_mask;
>>>>>> +
>>>>>> +    return val;
>>>>>> +}
>>>>>> +
>>>>>> +static int pmc_clk_mux_set_parent(struct clk_hw *hw, u8 index)
>>>>>> +{
>>>>>> +    struct pmc_clk *clk = to_pmc_clk(hw);
>>>>>> +    u32 val;
>>>>>> +
>>>>>> +    val = tegra_pmc_readl(pmc, clk->offs);
>>>>>> +    val &= ~(clk->mux_mask << clk->mux_shift);
>>>>>> +    val |= index << clk->mux_shift;
>>>>>> +    tegra_pmc_writel(pmc, val, clk->offs);
>>>>>> +    pmc_clk_fence_udelay(clk->offs);
>>>>>> +
>>>>>> +    return 0;
>>>>>> +}
>>>>>> +
>>>>>> +static int pmc_clk_is_enabled(struct clk_hw *hw)
>>>>>> +{
>>>>>> +    struct pmc_clk *clk = to_pmc_clk(hw);
>>>>>> +
>>>>>> +    return tegra_pmc_readl(pmc, clk->offs) & BIT(clk->gate_shift)
>>>>>> ? 1 : 0;
>>>>>> +}
>>>>>> +
>>>>>> +static void pmc_clk_set_state(unsigned long offs, u32 shift, int
>>>>>> state)
>>>>>> +{
>>>>>> +    u32 val;
>>>>>> +
>>>>>> +    val = tegra_pmc_readl(pmc, offs);
>>>>>> +    val = state ? (val | BIT(shift)) : (val & ~BIT(shift));
>>>>>> +    tegra_pmc_writel(pmc, val, offs);
>>>>>> +    pmc_clk_fence_udelay(offs);
>>>>>> +}
>>>>>> +
>>>>>> +static int pmc_clk_enable(struct clk_hw *hw)
>>>>>> +{
>>>>>> +    struct pmc_clk *clk = to_pmc_clk(hw);
>>>>>> +
>>>>>> +    pmc_clk_set_state(clk->offs, clk->gate_shift, 1);
>>>>>> +
>>>>>> +    return 0;
>>>>>> +}
>>>>>> +
>>>>>> +static void pmc_clk_disable(struct clk_hw *hw)
>>>>>> +{
>>>>>> +    struct pmc_clk *clk = to_pmc_clk(hw);
>>>>>> +
>>>>>> +    pmc_clk_set_state(clk->offs, clk->gate_shift, 0);
>>>>>> +}
>>>>>> +
>>>>>> +static const struct clk_ops pmc_clk_ops = {
>>>>>> +    .get_parent = pmc_clk_mux_get_parent,
>>>>>> +    .set_parent = pmc_clk_mux_set_parent,
>>>>>> +    .determine_rate = __clk_mux_determine_rate,
>>>>>> +    .is_enabled = pmc_clk_is_enabled,
>>>>>> +    .enable = pmc_clk_enable,
>>>>>> +    .disable = pmc_clk_disable,
>>>>>> +};
>>>>>> +
>>>>>> +static struct clk *
>>>>>> +tegra_pmc_clk_out_register(const struct pmc_clk_init_data *data,
>>>>>> +               unsigned long offset)
>>>>>> +{
>>>>>> +    struct clk_init_data init;
>>>>>> +    struct pmc_clk *pmc_clk;
>>>>>> +
>>>>>> +    pmc_clk = kzalloc(sizeof(*pmc_clk), GFP_KERNEL);
>>>>>> +    if (!pmc_clk)
>>>>>> +        return ERR_PTR(-ENOMEM);
>>>>>> +
>>>>>> +    init.name = data->name;
>>>>>> +    init.ops = &pmc_clk_ops;
>>>>>> +    init.parent_names = data->parents;
>>>>>> +    init.num_parents = data->num_parents;
>>>>>> +    init.flags = CLK_SET_RATE_NO_REPARENT | CLK_SET_RATE_PARENT |
>>>>>> +             CLK_SET_PARENT_GATE;
>>>>>> +
>>>>>> +    pmc_clk->hw.init = &init;
>>>>>> +    pmc_clk->offs = offset;
>>>>>> +    pmc_clk->mux_mask = 3;
>>>>> If mux_mask is a constant value, perhaps will be better to replace the
>>>>> variable with a literal?
>>>>>
>>>>> #define PMC_CLK_OUT_MUX_MASK    GENMASK(1, 0)
>>>> Maybe even:
>>>>
>>>> #define PMC_CLK_OUT_MUX_MASK(c)    GENMASK(c->shift + 1, c->shift)
>>>>
>>>>>> +    pmc_clk->mux_shift = data->mux_shift;
>>>>>> +    pmc_clk->gate_shift = data->gate_shift;
>>>>>> +
>>>>>> +    return clk_register(NULL, &pmc_clk->hw);
>>>>>> +}
>>>>>> +
>>>>>> +static void tegra_pmc_clock_register(struct tegra_pmc *pmc,
>>>>>> +                     struct device_node *np)
>>>>>> +{
>>>>>> +    struct clk *clk;
>>>>>> +    struct clk_onecell_data *clk_data;
>>>>>> +    unsigned int num_clks;
>>>>>> +    int i, err = -ENOMEM;
>>>>>> +
>>>>>> +    num_clks = pmc->soc->num_pmc_clks;
>>>>>> +
>>>>>> +    if (!num_clks)
>>>>>> +        return;
>>>>>> +
>>>>>> +    clk_data = kmalloc(sizeof(*clk_data), GFP_KERNEL);
>>>>>> +    if (!clk_data)
>>>>>> +        goto err_clk;
>>>>> What about devm_kmalloc, devm_kcalloc?
>>>>>
>>>>>> +    clk_data->clks = kcalloc(TEGRA_PMC_CLK_MAX,
>>>>>> sizeof(*clk_data->clks),
>>>>>> +                 GFP_KERNEL);
>>>>>> +    if (!clk_data->clks)
>>>>>> +        goto free_clkdata;
>>>>>> +
>>>>>> +    clk_data->clk_num = TEGRA_PMC_CLK_MAX;
>>>>>> +
>>>>>> +    for (i = 0; i < TEGRA_PMC_CLK_MAX; i++)
>>>>>> +        clk_data->clks[i] = ERR_PTR(-ENOENT);
>>>>>> +
>>>>>> +    for (i = 0; i < pmc->soc->num_pmc_clks; i++) {
>>>>>> +        const struct pmc_clk_init_data *data;
>>>>>> +
>>>>>> +        data = pmc->soc->pmc_clks_data + i;
>>>>>> +
>>>>>> +        clk = tegra_pmc_clk_out_register(data,
>>>>>> PMC_CLK_OUT_CNTRL);> +        if (IS_ERR(clk)) {
>>>>>> +            dev_err(pmc->dev,
>>>>>> +                "unable to register %s\n", data->name);
>>>>>> +            err = PTR_ERR(clk);
>>>>> Error codes in a message could be useful.
>>> Added error code at end of clock register along with WARN message to
>>> have it common to show warning with error code for all errors
>>> including kmalloc and kcalloc.
>>>
>> Sure, With devm_kmalloc and devm_kcalloc, will move error code along
>> with message and do return right at point of errors.
> There is no need to warn about memory allocations because there will be
> warning anyway, unless __GFP_NOWARN is used.

Earlier I had WARN message at each of errors during clock registers 
except during malloc/calloc.

When you suggested to add additional WARN message at the end of clock 
register in earlier feedback, thought you were suggesting to warn about 
kmalloc/kcalloc failures.

Probably I misunderstood your suggestion.

Anyways now with moving to devm malloc/calloc, will use dev_warn to show 
warning along with error code right at the point of error.

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