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Message-ID: <e5da42b8-bf21-4b57-8ae6-37ce6ca4210c@gmail.com>
Date: Tue, 3 Dec 2019 00:50:52 +0300
From: Dmitry Osipenko <digetx@...il.com>
To: Sowjanya Komatineni <skomatineni@...dia.com>,
thierry.reding@...il.com, jonathanh@...dia.com,
mperttunen@...dia.com, gregkh@...uxfoundation.org,
sboyd@...nel.org, tglx@...utronix.de, robh+dt@...nel.org,
mark.rutland@....com
Cc: allison@...utok.net, pdeschrijver@...dia.com, pgaikwad@...dia.com,
mturquette@...libre.com, horms+renesas@...ge.net.au,
Jisheng.Zhang@...aptics.com, krzk@...nel.org, arnd@...db.de,
spujar@...dia.com, josephl@...dia.com, vidyas@...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 v2 02/11] soc: tegra: Add Tegra PMC clock registrations
into PMC driver
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@...dia.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).
>>>>> + 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.
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