Re: [PATCH v4 06/19] soc: tegra: Add Tegra PMC clock registrations into PMC driver

Sowjanya Komatineni
2019-12-20T01:21:38Z

On 12/18/19 4:41 PM, Sowjanya Komatineni wrote:
>
> On 12/18/19 1:44 PM, Dmitry Osipenko wrote:
>> 18.12.2019 11:35, Dmitry Osipenko пишет:
>>> 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@nvidia.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)
>
> MUX Mask is used only here for PMC clock out and is same for all
> clk_out mux so will use
>
> #define PMC_CLK_OUT_MUX_MASK    GENMASK(1, 0)
>
>> I want to point out that may be a separated gate/mux shifts is a fine
>> variant, you should try and see whether another variants produce more
>> concise result.
>>
>> [snip]

We can do mux_shift as gate_shift + 4 and that restricts this clk
register only for clk1/2/3 as well and there are no other clocks in pmc
anyway.

How about using bit shift define for CLK1, CLK2, and CLK3?

.mux_shift = PMC_CLK1_SRC_SEL_SHIFT,

.gate_shift = PMC_CLK1_FORCE_EN_SHIFT,