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

[Sowjanya Komatineni <skomatineni@nvidia.com>]

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]);
>>>> +        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?

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.