Re: [PATCH v2 02/11] soc: tegra: Add Tegra PMC clock registrations into PMC driver

[Sowjanya Komatineni <skomatineni@nvidia.com>]

On 12/2/19 3:10 PM, Sowjanya Komatineni wrote:
>
> On 12/2/19 2:58 PM, Sowjanya Komatineni wrote:
>>
>> On 12/2/19 1:50 PM, Dmitry Osipenko wrote:
>>> 02.12.2019 23:09, Sowjanya Komatineni пишет:
>>>> On 11/28/19 5:25 AM, Dmitry Osipenko wrote:
>>>>> 28.11.2019 01:57, Sowjanya Komatineni пишет:
>>>>>> On 11/27/19 7:14 AM, Dmitry Osipenko wrote:
>>>>>>> 27.11.2019 07:59, Sowjanya Komatineni пишет:
>>>>>>>> Tegra210 and prior Tegra PMC has clk_out_1, clk_out_2, 
>>>>>>>> clk_out_3 with
>>>>>>>> mux and gate for each of these clocks.
>>>>>>>>
>>>>>>>> Currently these PMC clocks are registered by Tegra clock driver 
>>>>>>>> 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 clocks registration with PMC as a clock 
>>>>>>>> provider
>>>>>>>> for these clocks. clk_ops callback implementations for these 
>>>>>>>> clocks
>>>>>>>> uses tegra_pmc_readl and tegra_pmc_writel which supports PMC
>>>>>>>> programming
>>>>>>>> in secure mode and non-secure mode.
>>>>>>>>
>>>>>>>> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
>>>>>>>> ---
>>>>>>>>     drivers/soc/tegra/pmc.c | 330
>>>>>>>> ++++++++++++++++++++++++++++++++++++++++++++++++
>>>>>>>>     1 file changed, 330 insertions(+)
>>>>>>>>
>>>>>>>> diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
>>>>>>>> index ea0e11a09c12..a353f6d0a832 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 +160,91 @@
>>>>>>>>     #define  TEGRA_SMC_PMC_READ    0xaa
>>>>>>>>     #define  TEGRA_SMC_PMC_WRITE    0xbb
>>>>>>>>     +struct pmc_clk_mux {
>>>>>>>> +    struct clk_hw    hw;
>>>>>>>> +    unsigned long    offs;
>>>>>>>> +    u32        mask;
>>>>>>>> +    u32        shift;
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +#define to_pmc_clk_mux(_hw) container_of(_hw, struct 
>>>>>>>> pmc_clk_mux, hw)
>>>>>>>> +
>>>>>>>> +struct pmc_clk_gate {
>>>>>>>> +    struct clk_hw    hw;
>>>>>>>> +    unsigned long    offs;
>>>>>>>> +    u32        shift;
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +#define to_pmc_clk_gate(_hw) container_of(_hw, struct
>>>>>>>> pmc_clk_gate, hw)
>>>>>>>> +
>>>>>>>> +struct pmc_clk_init_data {
>>>>>>>> +    char *mux_name;
>>>>>>>> +    char *gate_name;
>>>>>>>> +    const char **parents;
>>>>>>>> +    int num_parents;
>>>>>>>> +    int mux_id;
>>>>>>>> +    int gate_id;
>>>>>>>> +    char *dev_name;
>>>>>>>> +    u8 mux_shift;
>>>>>>>> +    u8 gate_shift;
>>>>>>>> +    u8 init_parent_index;
>>>>>>>> +    int init_state;
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +static const char *clk_out1_parents[] = { "clk_m", "clk_m_div2",
>>>>>>>> +    "clk_m_div4", "extern1",
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +static const char *clk_out2_parents[] = { "clk_m", "clk_m_div2",
>>>>>>>> +    "clk_m_div4", "extern2",
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +static const char *clk_out3_parents[] = { "clk_m", "clk_m_div2",
>>>>>>>> +    "clk_m_div4", "extern3",
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +static struct pmc_clk_init_data tegra_pmc_clks_data[] = {
>>>>>>>> +    {
>>>>>>>> +        .mux_name = "clk_out_1_mux",
>>>>>>>> +        .gate_name = "clk_out_1",
>>>>>>>> +        .parents = clk_out1_parents,
>>>>>>>> +        .num_parents = ARRAY_SIZE(clk_out1_parents),
>>>>>>>> +        .mux_id = TEGRA_PMC_CLK_OUT_1_MUX,
>>>>>>>> +        .gate_id = TEGRA_PMC_CLK_OUT_1,
>>>>>>>> +        .dev_name = "extern1",
>>>>>>>> +        .mux_shift = 6,
>>>>>>>> +        .gate_shift = 2,
>>>>>>>> +        .init_parent_index = 3,
>>>>>>>> +        .init_state = 1,
>>>>>>>> +    },
>>>>>>>> +    {
>>>>>>>> +        .mux_name = "clk_out_2_mux",
>>>>>>>> +        .gate_name = "clk_out_2",
>>>>>>>> +        .parents = clk_out2_parents,
>>>>>>>> +        .num_parents = ARRAY_SIZE(clk_out2_parents),
>>>>>>>> +        .mux_id = TEGRA_PMC_CLK_OUT_2_MUX,
>>>>>>>> +        .gate_id = TEGRA_PMC_CLK_OUT_2,
>>>>>>>> +        .dev_name = "extern2",
>>>>>>>> +        .mux_shift = 14,
>>>>>>>> +        .gate_shift = 10,
>>>>>>>> +        .init_parent_index = 0,
>>>>>>>> +        .init_state = 0,
>>>>>>>> +    },
>>>>>>>> +    {
>>>>>>>> +        .mux_name = "clk_out_3_mux",
>>>>>>>> +        .gate_name = "clk_out_3",
>>>>>>>> +        .parents = clk_out3_parents,
>>>>>>>> +        .num_parents = ARRAY_SIZE(clk_out3_parents),
>>>>>>>> +        .mux_id = TEGRA_PMC_CLK_OUT_3_MUX,
>>>>>>>> +        .gate_id = TEGRA_PMC_CLK_OUT_3,
>>>>>>>> +        .dev_name = "extern3",
>>>>>>>> +        .mux_shift = 22,
>>>>>>>> +        .gate_shift = 18,
>>>>>>>> +        .init_parent_index = 0,
>>>>>>>> +        .init_state = 0,
>>>>>>>> +    },
>>>>>>>> +};
>>>>>>>> +
>>>>>>>>     struct tegra_powergate {
>>>>>>>>         struct generic_pm_domain genpd;
>>>>>>>>         struct tegra_pmc *pmc;
>>>>>>>> @@ -254,6 +344,9 @@ struct tegra_pmc_soc {
>>>>>>>>          */
>>>>>>>>         const struct tegra_wake_event *wake_events;
>>>>>>>>         unsigned int num_wake_events;
>>>>>>>> +
>>>>>>>> +    struct pmc_clk_init_data *pmc_clks_data;
>>>>>>>> +    unsigned int num_pmc_clks;
>>>>>>>>     };
>>>>>>>>       static const char * const tegra186_reset_sources[] = {
>>>>>>>> @@ -2163,6 +2256,228 @@ 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_mux *mux = to_pmc_clk_mux(hw);
>>>>>>>> +    int num_parents = clk_hw_get_num_parents(hw);
>>>>>>>> +    u32 val;
>>>>>>>> +
>>>>>>>> +    val = tegra_pmc_readl(pmc, mux->offs) >> mux->shift;
>>>>>>>> +    val &= mux->mask;
>>>>>>>> +
>>>>>>>> +    if (val >= num_parents)
>>>>>>>> +        return -EINVAL;
>>>>>>>> +
>>>>>>>> +    return val;
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +static int pmc_clk_mux_set_parent(struct clk_hw *hw, u8 index)
>>>>>>>> +{
>>>>>>>> +    struct pmc_clk_mux *mux = to_pmc_clk_mux(hw);
>>>>>>>> +    u32 val;
>>>>>>>> +
>>>>>>>> +    val = tegra_pmc_readl(pmc, mux->offs);
>>>>>>>> +    val &= ~(mux->mask << mux->shift);
>>>>>>>> +    val |= index << mux->shift;
>>>>>>>> +    tegra_pmc_writel(pmc, val, mux->offs);
>>>>>>>> +    pmc_clk_fence_udelay(mux->offs);
>>>>>>>> +
>>>>>>>> +    return 0;
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +static const struct clk_ops pmc_clk_mux_ops = {
>>>>>>>> +    .get_parent = pmc_clk_mux_get_parent,
>>>>>>>> +    .set_parent = pmc_clk_mux_set_parent,
>>>>>>>> +    .determine_rate = __clk_mux_determine_rate,
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +static struct clk *
>>>>>>>> +tegra_pmc_clk_mux_register(const char *name, const char * const
>>>>>>>> *parent_names,
>>>>>>>> +               int num_parents, unsigned long flags,
>>>>>>>> +               unsigned long offset, u32 shift, u32 mask)
>>>>>>>> +{
>>>>>>>> +    struct clk_init_data init;
>>>>>>>> +    struct pmc_clk_mux *mux;
>>>>>>>> +
>>>>>>>> +    mux = kzalloc(sizeof(*mux), GFP_KERNEL);
>>>>>>>> +    if (!mux)
>>>>>>>> +        return ERR_PTR(-ENOMEM);
>>>>>>>> +
>>>>>>>> +    init.name = name;
>>>>>>>> +    init.ops = &pmc_clk_mux_ops;
>>>>>>>> +    init.parent_names = parent_names;
>>>>>>>> +    init.num_parents = num_parents;
>>>>>>>> +    init.flags = flags;
>>>>>>>> +
>>>>>>>> +    mux->hw.init = &init;
>>>>>>>> +    mux->offs = offset;
>>>>>>>> +    mux->mask = mask;
>>>>>>>> +    mux->shift = shift;
>>>>>>>> +
>>>>>>>> +    return clk_register(NULL, &mux->hw);
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +static int pmc_clk_is_enabled(struct clk_hw *hw)
>>>>>>>> +{
>>>>>>>> +    struct pmc_clk_gate *gate = to_pmc_clk_gate(hw);
>>>>>>>> +
>>>>>>>> +    return tegra_pmc_readl(pmc, gate->offs) & BIT(gate->shift) 
>>>>>>>> ? 1
>>>>>>>> : 0;
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +static void pmc_clk_set_state(struct clk_hw *hw, int state)
>>>>>>>> +{
>>>>>>>> +    struct pmc_clk_gate *gate = to_pmc_clk_gate(hw);
>>>>>>>> +    u32 val;
>>>>>>>> +
>>>>>>>> +    val = tegra_pmc_readl(pmc, gate->offs);
>>>>>>>> +    val = state ? (val | BIT(gate->shift)) : (val &
>>>>>>>> ~BIT(gate->shift));
>>>>>>>> +    tegra_pmc_writel(pmc, val, gate->offs);
>>>>>>>> +    pmc_clk_fence_udelay(gate->offs);
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +static int pmc_clk_enable(struct clk_hw *hw)
>>>>>>>> +{
>>>>>>>> +    pmc_clk_set_state(hw, 1);
>>>>>>>> +
>>>>>>>> +    return 0;
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +static void pmc_clk_disable(struct clk_hw *hw)
>>>>>>>> +{
>>>>>>>> +    pmc_clk_set_state(hw, 0);
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +static const struct clk_ops pmc_clk_gate_ops = {
>>>>>>>> +    .is_enabled = pmc_clk_is_enabled,
>>>>>>>> +    .enable = pmc_clk_enable,
>>>>>>>> +    .disable = pmc_clk_disable,
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +static struct clk *
>>>>>>>> +tegra_pmc_clk_gate_register(const char *name, const char
>>>>>>>> *parent_name,
>>>>>>>> +                unsigned long flags, unsigned long offset,
>>>>>>>> +                u32 shift)
>>>>>>>> +{
>>>>>>>> +    struct clk_init_data init;
>>>>>>>> +    struct pmc_clk_gate *gate;
>>>>>>>> +
>>>>>>>> +    gate = kzalloc(sizeof(*gate), GFP_KERNEL);
>>>>>>>> +    if (!gate)
>>>>>>>> +        return ERR_PTR(-ENOMEM);
>>>>>>>> +
>>>>>>>> +    init.name = name;
>>>>>>>> +    init.ops = &pmc_clk_gate_ops;
>>>>>>>> +    init.parent_names = &parent_name;
>>>>>>>> +    init.num_parents = 1;
>>>>>>>> +    init.flags = flags;
>>>>>>>> +
>>>>>>>> +    gate->hw.init = &init;
>>>>>>>> +    gate->offs = offset;
>>>>>>>> +    gate->shift = shift;
>>>>>>>> +
>>>>>>>> +    return clk_register(NULL, &gate->hw);
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +static void tegra_pmc_clock_register(struct tegra_pmc *pmc,
>>>>>>>> +                     struct device_node *np)
>>>>>>>> +{
>>>>>>>> +    struct clk *clkmux, *clk, *parent;
>>>>>>>> +    struct clk_onecell_data *clk_data;
>>>>>>>> +    unsigned int num_clks;
>>>>>>>> +    int i, ret;
>>>>>>>> +
>>>>>>>> +    /* each pmc clock output has a mux and a gate */
>>>>>>>> +    num_clks = pmc->soc->num_pmc_clks * 2;
>>>>>>>> +
>>>>>>>> +    if (!num_clks)
>>>>>>>> +        return;
>>>>>>>> +
>>>>>>>> +    clk_data = kmalloc(sizeof(*clk_data), GFP_KERNEL);
>>>>>>>> +    if (!clk_data)
>>>>>>>> +        return;
>>>>>>>> +
>>>>>>>> +    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 = num_clks;
>>>>>>>> +
>>>>>>>> +    for (i = 0; i < pmc->soc->num_pmc_clks; i++) {
>>>>>>>> +        struct pmc_clk_init_data *data;
>>>>>>>> +
>>>>>>>> +        data = pmc->soc->pmc_clks_data + i;
>>>>>>>> +
>>>>>>>> +        clkmux = tegra_pmc_clk_mux_register(data->mux_name,
>>>>>>>> +                            data->parents,
>>>>>>>> +                            data->num_parents,
>>>>>>>> + CLK_SET_RATE_NO_REPARENT |
>>>>>>>> +                            CLK_SET_RATE_PARENT,
>>>>>>>> +                            PMC_CLK_OUT_CNTRL,
>>>>>>>> +                            data->mux_shift, 3);
>>>>>>>> +        if (IS_ERR(clkmux))
>>>>>>>> +            goto free_clks;
>>>>>>>> +
>>>>>>>> +        clk_data->clks[data->mux_id] = clkmux;
>>>>>>>> +
>>>>>>>> +        clk = tegra_pmc_clk_gate_register(data->gate_name,
>>>>>>>> +                          data->mux_name,
>>>>>>>> +                          CLK_SET_RATE_PARENT,
>>>>>>>> +                          PMC_CLK_OUT_CNTRL,
>>>>>>>> +                          data->gate_shift);
>>>>>>>> +        if (IS_ERR(clk))
>>>>>>>> +            goto free_clks;
>>>>>>>> +
>>>>>>>> +        clk_data->clks[data->gate_id] = clk;
>>>>>>>> +
>>>>>>>> +        ret = clk_set_parent(clk, clkmux);
>>>>>>>> +        if (ret < 0) {
>>>>>>>> +            pr_err("failed to set parent of %s to %s\n",
>>>>>>>> +                   __func__, __clk_get_name(clk),
>>>>>>>> +                   __clk_get_name(clkmux));
>>>>>>>> +        }
>>>>>>>> +
>>>>>>>> +        clk_register_clkdev(clk, data->dev_name, 
>>>>>>>> data->gate_name);
>>>>>>>> +
>>>>>>>> +        /* configure initial clock parent and state */
>>>>>>>> +        parent = clk_get_sys(data->gate_name,
>>>>>>>> + data->parents[data->init_parent_index]);
>>> Couldn't the default parent be defined using "assigned clock" in a
>>> device-tree? Please see "Assigned clock parents and rates" in the doc.
>>>
>>> https://www.kernel.org/doc/Documentation/devicetree/bindings/clock/clock-bindings.txt 
>>>
>>>
>>> Then you could simply use of_clk_set_defaults(pmc->dev->of_node, true).
>>
>> Yes, of_clk_add_provider() does of_clk_set_defaults which sets based 
>> on assigned parents and clock rates.
>>
>> This need device tree to specify assigned clock parent properties. 
>> Will update device tree and remove init parent from the driver.
>>
> assigned-clock properties should be set in consumer node of these 
> clocks and currently these clocks are not used yet.
>
> So will just remove init parent from driver and when these clocks are 
> used device tree can be updated in corresponding consumer node with 
> these properties.
>
How about default ON/OFF init state for the clocks? I see assigned-clock 
properties for parent and rate only.

But based on existing clock-tegra-pmc driver, I see clk_out_1 is default 
enabled with extern1 parent for T30 thru T210 platforms.

Peter/Thierry, What was the reason we enable clk_out_1 right from the 
clock registration?

>>>
>>>>>>>> +        if (!IS_ERR(parent)) {
>>>>>>>> +            ret = clk_set_parent(clkmux, parent);
>>>>>>>> +            if (ret < 0) {
>>>>>>>> +                pr_err("failed to set parent of %s to %s\n",
>>>>>>>> +                       __func__, __clk_get_name(clkmux),
>>>>>>>> +                       __clk_get_name(parent));
>>>>>>>> +                WARN_ON(1);
>>>>>>>> +            }
>>>>>>>> +        }
>>>>>>>> +
>>>>>>>> +        if (data->init_state) {
>>>>>>>> +            if (clk_prepare_enable(clk)) {
>>>>>>>> +                pr_err("failed to enable %s\n", __func__,
>>>>>>>> +                       __clk_get_name(clk));
>>>>>>>> +                WARN_ON(1);
>>>>> Alternatively you could write it like this:
>>>>>
>>>>>      err = clk_prepare_enable(clk);
>>>>>
>>>>>      WARN_ON(err, "failed to enable %s: %d\n",
>>>>>          __clk_get_name(clk), err);
>>>>>
>>>>>>> Should be a bit better to move the WARN_ON to the end of errors
>>>>>>> handling
>>>>>>> in order to catch all possible errors:
>>>>>>>
>>>>>>> @@ -2510,6 +2510,7 @@ static void tegra_pmc_clock_register(struct
>>>>>>> tegra_pmc *pmc,
>>>>>>>            return;
>>>>>>>
>>>>>>>     free_clks:
>>>>>>> +       WARN_ON(1);
>>>>>>>            kfree(clk_data->clks);
>>>>>>>     free_clkdata:
>>>>>>>            kfree(clk_data);
>>>>>> Reason I had WARN_ON right during clk_set_parent failure is to 
>>>>>> have the
>>>>>> loop continue for subsequence pmc clocks registration instead of
>>>>>> terminating all pmc clocks registration.
>>>>> Ah, okay. Nevertheless this WARN_ON in the end shouldn't be the least
>>>>> (IMO).
>>>> Hi Dmitry, Just want to be clear on the above comment. Are you
>>>> suggesting to add additional WARN_ON at the end?
>>> Yes, it was my suggestion.
>>>
>>>> Thought WARN_ON right during corresponding clock failure with warn
>>>> message showing clock names will be clear and also other clocks still
>>>> should be registered.
>>>>
>>>> To add additional WARN_ON at the end need to track status of each 
>>>> clock
>>>> and use that to as warn condition.
>>> You could add a warning/error message to every point of failure.
>>>
>>> Primarily, it is important not to miss a error. Secondarily, it is
>>> important to make diagnostic message meaningful.
>>>
>>> Realistically, I doubt that this chunk of code will ever fail once 
>>> it is
>>> known to work well. So it will be nice to have a more detailed
>>> diagnostics (just in a case), but it shouldn't be a must.
>>
>> OK, Will add additional WARN message "failed registering PMC clocks" 
>> at the end.
>>