Date:   Thu, 2 Jul 2020 01:17:45 +0800
From:   Zhou Yanjie <zhouyanjie@...yeetech.com>
To:     Paul Cercueil <paul@...pouillou.net>
Cc:     linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        daniel.lezcano@...aro.org, tglx@...utronix.de, robh+dt@...nel.org,
        dongsheng.qiu@...enic.com, aric.pzqi@...enic.com,
        rick.tyliu@...enic.com, yanfei.li@...enic.com,
        sernia.zhou@...mail.com, zhenwenjin@...il.com
Subject: Re: [PATCH v3 2/2] clocksource: Ingenic: Add support for the Ingenic
 X1000 OST.

Hi Paul,

在 2020/7/1 上午3:38, Paul Cercueil 写道:
> Hi Zhou,
>
> Le mer. 1 juil. 2020 à 1:15, 周琰杰 (Zhou Yanjie) 
> <zhouyanjie@...yeetech.com> a écrit :
>> X1000 and SoCs after X1000 (such as X1500 and X1830) had a separate
>> OST, it no longer belongs to TCU. This driver will register both a
>> clocksource and a sched_clock to the system.
>>
>> Tested-by: 周正 (Zhou Zheng) <sernia.zhou@...mail.com>
>> Co-developed-by: 漆鹏振 (Qi Pengzhen) <aric.pzqi@...enic.com>
>> Signed-off-by: 漆鹏振 (Qi Pengzhen) <aric.pzqi@...enic.com>
>> Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@...yeetech.com>
>> ---
>>
>> Notes:
>>     v1->v2:
>>     Fix compile warnings.
>>     Reported-by: kernel test robot <lkp@...el.com>
>>
>>     v2->v3:
>>     No change.
>>
>>  drivers/clocksource/Kconfig          |  19 +-
>>  drivers/clocksource/Makefile         |   1 +
>>  drivers/clocksource/ingenic-sysost.c | 509 
>> +++++++++++++++++++++++++++++++++++
>>  3 files changed, 525 insertions(+), 4 deletions(-)
>>  create mode 100644 drivers/clocksource/ingenic-sysost.c
>>
>> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
>> index 91418381fcd4..172397a00f3e 100644
>> --- a/drivers/clocksource/Kconfig
>> +++ b/drivers/clocksource/Kconfig
>> @@ -686,7 +686,7 @@ config MILBEAUT_TIMER
>>        Enables the support for Milbeaut timer driver.
>>
>>  config INGENIC_TIMER
>> -    bool "Clocksource/timer using the TCU in Ingenic JZ SoCs"
>> +    bool "Clocksource/timer using the TCU in Ingenic SoCs"
>
> This cosmetic change is unrelated to the patch, please drop it.
>

Sure.


>>      default MACH_INGENIC
>>      depends on MIPS || COMPILE_TEST
>>      depends on COMMON_CLK
>> @@ -694,15 +694,26 @@ config INGENIC_TIMER
>>      select TIMER_OF
>>      select IRQ_DOMAIN
>>      help
>> -      Support for the timer/counter unit of the Ingenic JZ SoCs.
>> +      Support for the timer/counter unit of the Ingenic SoCs.
>
> Same here.
>

Sure.


>> +
>> +config INGENIC_SYSOST
>> +    bool "Clocksource/timer using the SYSOST in Ingenic SoCs"
>> +    default MACH_INGENIC
>> +    depends on MIPS || COMPILE_TEST
>> +    depends on COMMON_CLK
>> +    select MFD_SYSCON
>> +    select TIMER_OF
>> +    select IRQ_DOMAIN
>> +    help
>> +      This option enables support for SYSOST in Ingenic SoCs .
>>
>>  config INGENIC_OST
>> -    bool "Clocksource for Ingenic OS Timer"
>> +    bool "Clocksource for Ingenic OST"
>
> Same here.
>

OK.


>>      depends on MIPS || COMPILE_TEST
>>      depends on COMMON_CLK
>>      select MFD_SYSCON
>>      help
>> -      Support for the Operating System Timer of the Ingenic JZ SoCs.
>> +      Support for the Operating System Timer of the Ingenic SoCs.
>
> Same here.
>

Sure.


>>
>>  config MICROCHIP_PIT64B
>>      bool "Microchip PIT64B support"
>> diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
>> index bdda1a2e4097..3994e221e262 100644
>> --- a/drivers/clocksource/Makefile
>> +++ b/drivers/clocksource/Makefile
>> @@ -82,6 +82,7 @@ obj-$(CONFIG_H8300_TMR8)        += h8300_timer8.o
>>  obj-$(CONFIG_H8300_TMR16)        += h8300_timer16.o
>>  obj-$(CONFIG_H8300_TPU)            += h8300_tpu.o
>>  obj-$(CONFIG_INGENIC_OST)        += ingenic-ost.o
>> +obj-$(CONFIG_INGENIC_SYSOST)    += ingenic-sysost.o
>>  obj-$(CONFIG_INGENIC_TIMER)        += ingenic-timer.o
>>  obj-$(CONFIG_CLKSRC_ST_LPC)        += clksrc_st_lpc.o
>>  obj-$(CONFIG_X86_NUMACHIP)        += numachip.o
>> diff --git a/drivers/clocksource/ingenic-sysost.c 
>> b/drivers/clocksource/ingenic-sysost.c
>> new file mode 100644
>> index 000000000000..d3e1b7582221
>> --- /dev/null
>> +++ b/drivers/clocksource/ingenic-sysost.c
>> @@ -0,0 +1,509 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Ingenic XBurst SoCs SYSOST clocks driver
>> + * Copyright (c) 2020 周琰杰 (Zhou Yanjie) <zhouyanjie@...yeetech.com>
>> + */
>> +
>> +#include <linux/bitops.h>
>> +#include <linux/clk.h>
>> +#include <linux/clk-provider.h>
>> +#include <linux/clockchips.h>
>> +#include <linux/clocksource.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_irq.h>
>> +#include <linux/sched_clock.h>
>> +#include <linux/slab.h>
>> +#include <linux/syscore_ops.h>
>> +
>> +#include <dt-bindings/clock/ingenic,ost.h>
>> +
>> +/* OST register offsets */
>> +#define OST_REG_OSTCCR            0x00
>> +#define OST_REG_OSTCR            0x08
>> +#define OST_REG_OSTFR            0x0c
>> +#define OST_REG_OSTMR            0x10
>> +#define OST_REG_OST1DFR            0x14
>> +#define OST_REG_OST1CNT            0x18
>> +#define OST_REG_OST2CNTL        0x20
>> +#define OST_REG_OSTCNT2HBUF        0x24
>> +#define OST_REG_OSTESR            0x34
>> +#define OST_REG_OSTECR            0x38
>> +
>> +/* bits within the OSTCCR register */
>> +#define OSTCCR_PRESCALE1_MASK    0x3
>> +#define OSTCCR_PRESCALE2_MASK    0xc
>> +#define OSTCCR_PRESCALE1_LSB    0
>> +#define OSTCCR_PRESCALE2_LSB    2
>> +
>> +/* bits within the OSTCR register */
>> +#define OSTCR_OST1CLR            BIT(0)
>> +#define OSTCR_OST2CLR            BIT(1)
>> +
>> +/* bits within the OSTFR register */
>> +#define OSTFR_FFLAG                BIT(0)
>> +
>> +/* bits within the OSTMR register */
>> +#define OSTMR_FMASK                BIT(0)
>> +
>> +/* bits within the OSTESR register */
>> +#define OSTESR_OST1ENS            BIT(0)
>> +#define OSTESR_OST2ENS            BIT(1)
>> +
>> +/* bits within the OSTECR register */
>> +#define OSTECR_OST1ENC            BIT(0)
>> +#define OSTECR_OST2ENC            BIT(1)
>> +
>> +enum ost_clk_parent {
>> +    OST_PARENT_EXT,
>> +};
>> +
>> +struct ingenic_soc_info {
>> +    unsigned int num_channels;
>> +};
>
> Unless you plan to add support for other SoCs which have more than 2 
> channels, I think you can drop this - just add a OST_NUM_CHANNELS macro.
>

When X2000 turned on SMT, a total of 3 channels are required, this is 
reserved for adding support for X2000 in the future.


>> +
>> +struct ingenic_ost_clk_info {
>> +    struct clk_init_data init_data;
>> +    u8 ostccr_reg;
>> +};
>> +
>> +struct ingenic_ost_clk {
>> +    struct clk_hw hw;
>> +    unsigned int idx;
>> +    struct ingenic_ost *ost;
>> +    const struct ingenic_ost_clk_info *info;
>> +};
>> +
>> +struct ingenic_ost {
>> +    void __iomem *base;
>> +    const struct ingenic_soc_info *soc_info;
>> +    struct clk *clk, *percpu_timer_clk, *global_timer_clk;
>> +    unsigned int percpu_timer_channel, global_timer_channel;
>> +    struct clock_event_device cevt;
>> +    struct clocksource cs;
>> +    char name[20];
>> +
>> +    struct clk_hw_onecell_data *clocks;
>> +};
>> +
>> +static struct ingenic_ost *ingenic_ost;
>> +
>> +static inline struct ingenic_ost_clk *to_ost_clk(struct clk_hw *hw)
>> +{
>> +    return container_of(hw, struct ingenic_ost_clk, hw);
>> +}
>> +
>> +static unsigned long ingenic_ost_recalc_rate(struct clk_hw *hw,
>> +        unsigned long parent_rate)
>> +{
>> +    struct ingenic_ost_clk *ost_clk = to_ost_clk(hw);
>> +    const struct ingenic_ost_clk_info *info = ost_clk->info;
>> +    unsigned int prescale;
>> +
>> +    prescale = readl(ost_clk->ost->base + info->ostccr_reg);
>> +
>> +    if (ost_clk->idx == OST_CLK_PERCPU_TIMER)
>> +        prescale = (prescale & OSTCCR_PRESCALE1_MASK) >> 
>> OSTCCR_PRESCALE1_LSB;
>> +    else if (ost_clk->idx == OST_CLK_GLOBAL_TIMER)
>> +        prescale = (prescale & OSTCCR_PRESCALE2_MASK) >> 
>> OSTCCR_PRESCALE2_LSB;
>
> Instead of checking which clock you're manipulating here, just set a 
> different .recalc_rate to the two clocks.
>

Sure.


>> +
>> +    return parent_rate >> (prescale * 2);
>> +}
>> +
>> +static u8 ingenic_ost_get_prescale(unsigned long rate, unsigned long 
>> req_rate)
>> +{
>> +    u8 prescale;
>> +
>> +    for (prescale = 0; prescale < 2; prescale++)
>> +        if ((rate >> (prescale * 2)) <= req_rate)
>> +            return prescale;
>> +
>> +    return 2; /* /16 divider */
>> +}
>> +
>> +static long ingenic_ost_round_rate(struct clk_hw *hw, unsigned long 
>> req_rate,
>> +        unsigned long *parent_rate)
>> +{
>> +    unsigned long rate = *parent_rate;
>> +    u8 prescale;
>> +
>> +    if (req_rate > rate)
>> +        return rate;
>> +
>> +    prescale = ingenic_ost_get_prescale(rate, req_rate);
>> +
>> +    return rate >> (prescale * 2);
>> +}
>> +
>> +static int ingenic_ost_set_rate(struct clk_hw *hw, unsigned long 
>> req_rate,
>> +        unsigned long parent_rate)
>> +{
>> +    struct ingenic_ost_clk *ost_clk = to_ost_clk(hw);
>> +    const struct ingenic_ost_clk_info *info = ost_clk->info;
>> +    u8 prescale = ingenic_ost_get_prescale(parent_rate, req_rate);
>> +    int val;
>> +
>> +    if (ost_clk->idx == OST_CLK_PERCPU_TIMER) {
>> +        val = readl(ost_clk->ost->base + info->ostccr_reg);
>> +        val = (val & ~OSTCCR_PRESCALE1_MASK) | (prescale << 
>> OSTCCR_PRESCALE1_LSB);
>> +        writel(val, ost_clk->ost->base + info->ostccr_reg);
>> +    } else if (ost_clk->idx == OST_CLK_GLOBAL_TIMER) {
>> +        val = readl(ost_clk->ost->base + info->ostccr_reg);
>> +        val = (val & ~OSTCCR_PRESCALE2_MASK) | (prescale << 
>> OSTCCR_PRESCALE2_LSB);
>> +        writel(val, ost_clk->ost->base + info->ostccr_reg);
>> +    }
>
> Same here - set a different .set_rate() callback to the two clocks.
>

Sure.


>> +
>> +    return 0;
>> +}
>> +
>> +static const struct clk_ops ingenic_ost_clk_ops = {
>> +    .recalc_rate    = ingenic_ost_recalc_rate,
>> +    .round_rate    = ingenic_ost_round_rate,
>> +    .set_rate    = ingenic_ost_set_rate,
>> +};
>> +
>> +static const char * const ingenic_ost_clk_parents[] = {
>> +    [OST_PARENT_EXT]  = "ext",
>> +};
>
> just { "ext" } will be fine, no need to specify the index, which is 
> zero anyway. Then you can drop the ost_clock_parent enum.
>

OK.


>> +
>> +#define DEF_TIMER(_name, _ostccr) { \
>> +    .init_data = { \
>> +        .name = _name, \
>> +        .parent_names = ingenic_ost_clk_parents, \
>> +        .num_parents = ARRAY_SIZE(ingenic_ost_clk_parents), \
>> +        .ops = &ingenic_ost_clk_ops, \
>> +        .flags = CLK_SET_RATE_UNGATE, \
>> +    }, \
>> +    .ostccr_reg = _ostccr, \
>> +}
>> +
>> +static const struct ingenic_ost_clk_info ingenic_ost_clk_info[] = {
>> +    [OST_CLK_PERCPU_TIMER] = DEF_TIMER("percpu timer", OST_REG_OSTCCR),
>> +    [OST_CLK_GLOBAL_TIMER] = DEF_TIMER("global timer", OST_REG_OSTCCR),
>> +};
>> +
>> +#undef DEF_TIMER
>> +
>> +static u64 notrace ingenic_ost_global_timer_read_cntl(void)
>> +{
>> +    struct ingenic_ost *ost = ingenic_ost;
>> +    unsigned int count;
>> +
>> +    count = readl(ost->base + OST_REG_OST2CNTL);
>> +
>> +    return count;
>> +}
>> +
>> +static u64 notrace ingenic_ost_clocksource_read(struct clocksource *cs)
>> +{
>> +    return ingenic_ost_global_timer_read_cntl();
>> +}
>> +
>> +static inline struct ingenic_ost *to_ingenic_ost(struct 
>> clock_event_device *evt)
>> +{
>> +    return container_of(evt, struct ingenic_ost, cevt);
>> +}
>> +
>> +static int ingenic_ost_cevt_set_state_shutdown(struct 
>> clock_event_device *evt)
>> +{
>> +    struct ingenic_ost *ost = to_ingenic_ost(evt);
>> +
>> +    writel(OSTECR_OST1ENC, ost->base + OST_REG_OSTECR);
>> +
>> +    return 0;
>> +}
>> +
>> +static int ingenic_ost_cevt_set_next(unsigned long next,
>> +                     struct clock_event_device *evt)
>> +{
>> +    struct ingenic_ost *ost = to_ingenic_ost(evt);
>> +
>> +    writel((u32)~OSTFR_FFLAG, ost->base + OST_REG_OSTFR);
>> +    writel(next, ost->base + OST_REG_OST1DFR);
>> +    writel(OSTCR_OST1CLR, ost->base + OST_REG_OSTCR);
>> +    writel(OSTESR_OST1ENS, ost->base + OST_REG_OSTESR);
>> +    writel((u32)~OSTMR_FMASK, ost->base + OST_REG_OSTMR);
>> +
>> +    return 0;
>> +}
>> +
>> +static irqreturn_t ingenic_ost_cevt_cb(int irq, void *dev_id)
>> +{
>> +    struct clock_event_device *evt = dev_id;
>> +    struct ingenic_ost *ost = to_ingenic_ost(evt);
>> +
>> +    writel(OSTECR_OST1ENC, ost->base + OST_REG_OSTECR);
>> +
>> +    if (evt->event_handler)
>> +        evt->event_handler(evt);
>> +
>> +    return IRQ_HANDLED;
>> +}
>> +
>> +static int __init ingenic_ost_register_clock(struct ingenic_ost *ost,
>> +            unsigned int idx, const struct ingenic_ost_clk_info *info,
>> +            struct clk_hw_onecell_data *clocks)
>> +{
>> +    struct ingenic_ost_clk *ost_clk;
>> +    int val, err;
>> +
>> +    ost_clk = kzalloc(sizeof(*ost_clk), GFP_KERNEL);
>> +    if (!ost_clk)
>> +        return -ENOMEM;
>> +
>> +    ost_clk->hw.init = &info->init_data;
>> +    ost_clk->idx = idx;
>> +    ost_clk->info = info;
>> +    ost_clk->ost = ost;
>> +
>> +    /* Reset clock divider */
>> +    val = readl(ost->base + info->ostccr_reg);
>> +    val &= ~(OSTCCR_PRESCALE1_MASK | OSTCCR_PRESCALE2_MASK);
>> +    writel(val, ost->base + info->ostccr_reg);
>> +
>> +    err = clk_hw_register(NULL, &ost_clk->hw);
>> +    if (err) {
>> +        kfree(ost_clk);
>> +        return err;
>> +    }
>> +
>> +    clocks->hws[idx] = &ost_clk->hw;
>> +
>> +    return 0;
>> +}
>> +
>> +static struct clk * __init ingenic_ost_get_clock(struct device_node 
>> *np, int id)
>> +{
>> +    struct of_phandle_args args;
>> +
>> +    args.np = np;
>> +    args.args_count = 1;
>> +    args.args[0] = id;
>> +
>> +    return of_clk_get_from_provider(&args);
>> +}
>> +
>> +static int __init ingenic_ost_percpu_timer_init(struct device_node *np,
>> +                     struct ingenic_ost *ost)
>> +{
>> +    unsigned int timer_virq, channel = ost->percpu_timer_channel;
>> +    unsigned long rate;
>> +    int err;
>> +
>> +    ost->percpu_timer_clk = ingenic_ost_get_clock(np, channel);
>> +    if (IS_ERR(ost->percpu_timer_clk))
>> +        return PTR_ERR(ost->percpu_timer_clk);
>> +
>> +    err = clk_prepare_enable(ost->percpu_timer_clk);
>> +    if (err)
>> +        goto err_clk_put;
>> +
>> +    rate = clk_get_rate(ost->percpu_timer_clk);
>> +    if (!rate) {
>> +        err = -EINVAL;
>> +        goto err_clk_disable;
>> +    }
>> +
>> +    timer_virq = of_irq_get(np, 0);
>> +    if (!timer_virq) {
>> +        err = -EINVAL;
>> +        goto err_clk_disable;
>> +    }
>> +
>> +    snprintf(ost->name, sizeof(ost->name), "OST percpu timer");
>> +
>> +    err = request_irq(timer_virq, ingenic_ost_cevt_cb, IRQF_TIMER,
>> +              ost->name, &ost->cevt);
>> +    if (err)
>> +        goto err_irq_dispose_mapping;
>> +
>> +    ost->cevt.cpumask = cpumask_of(smp_processor_id());
>> +    ost->cevt.features = CLOCK_EVT_FEAT_ONESHOT;
>> +    ost->cevt.name = ost->name;
>> +    ost->cevt.rating = 400;
>> +    ost->cevt.set_state_shutdown = ingenic_ost_cevt_set_state_shutdown;
>> +    ost->cevt.set_next_event = ingenic_ost_cevt_set_next;
>> +
>> +    clockevents_config_and_register(&ost->cevt, rate, 4, 0xffffffff);
>> +
>> +    return 0;
>> +
>> +err_irq_dispose_mapping:
>> +    irq_dispose_mapping(timer_virq);
>> +err_clk_disable:
>> +    clk_disable_unprepare(ost->percpu_timer_clk);
>> +err_clk_put:
>> +    clk_put(ost->percpu_timer_clk);
>> +    return err;
>> +}
>> +
>> +static int __init ingenic_ost_global_timer_init(struct device_node *np,
>> +                           struct ingenic_ost *ost)
>> +{
>> +    unsigned int channel = ost->global_timer_channel;
>> +    struct clocksource *cs = &ost->cs;
>> +    unsigned long rate;
>> +    int err;
>> +
>> +    ost->global_timer_clk = ingenic_ost_get_clock(np, channel);
>> +    if (IS_ERR(ost->global_timer_clk))
>> +        return PTR_ERR(ost->global_timer_clk);
>> +
>> +    err = clk_prepare_enable(ost->global_timer_clk);
>> +    if (err)
>> +        goto err_clk_put;
>> +
>> +    rate = clk_get_rate(ost->global_timer_clk);
>> +    if (!rate) {
>> +        err = -EINVAL;
>> +        goto err_clk_disable;
>> +    }
>> +
>> +    /* Clear counter CNT registers */
>> +    writel(OSTCR_OST2CLR, ost->base + OST_REG_OSTCR);
>> +
>> +    /* Enable OST channel */
>> +    writel(OSTESR_OST2ENS, ost->base + OST_REG_OSTESR);
>> +
>> +    cs->name = "ingenic-ost";
>> +    cs->rating = 400;
>> +    cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
>> +    cs->mask = CLOCKSOURCE_MASK(32);
>> +    cs->read = ingenic_ost_clocksource_read;
>> +
>> +    err = clocksource_register_hz(cs, rate);
>> +    if (err)
>> +        goto err_clk_disable;
>> +
>> +    return 0;
>> +
>> +err_clk_disable:
>> +    clk_disable_unprepare(ost->global_timer_clk);
>> +err_clk_put:
>> +    clk_put(ost->global_timer_clk);
>> +    return err;
>> +}
>> +
>> +static const struct ingenic_soc_info x1000_soc_info = {
>> +    .num_channels = 2,
>> +};
>> +
>> +static const struct of_device_id __maybe_unused 
>> ingenic_ost_of_match[] __initconst = {
>> +    { .compatible = "ingenic,x1000-ost", .data = &x1000_soc_info, },
>> +    { /* sentinel */ }
>> +};
>> +
>> +static int __init ingenic_ost_probe(struct device_node *np)
>> +{
>> +    const struct of_device_id *id = 
>> of_match_node(ingenic_ost_of_match, np);
>> +    struct ingenic_ost *ost;
>> +    unsigned int i;
>> +    int ret;
>> +
>> +    ost = kzalloc(sizeof(*ost), GFP_KERNEL);
>> +    if (!ost)
>> +        return -ENOMEM;
>> +
>> +    ost->base = of_iomap(np, 0);
>> +    if (IS_ERR(ost->base)) {
>> +        pr_err("%s: Failed to map OST registers\n", __func__);
>> +        ret = PTR_ERR(ost->base);
>> +        goto err_free_ost;
>> +    }
>> +
>> +    ost->clk = of_clk_get_by_name(np, "ost");
>> +    if (IS_ERR(ost->clk)) {
>> +        ret = PTR_ERR(ost->clk);
>> +        pr_crit("%s: Cannot get OST clock\n", __func__);
>> +        goto err_free_ost;
>> +    }
>> +
>> +    ret = clk_prepare_enable(ost->clk);
>> +    if (ret) {
>> +        pr_crit("%s: Unable to enable OST clock\n", __func__);
>> +        goto err_put_clk;
>> +    }
>> +
>> +    ost->soc_info = id->data;
>> +
>> +    ost->clocks = kzalloc(struct_size(ost->clocks, hws, 
>> ost->soc_info->num_channels),
>> +                  GFP_KERNEL);
>> +    if (!ost->clocks) {
>> +        ret = -ENOMEM;
>> +        goto err_clk_disable;
>> +    }
>> +
>> +    ost->clocks->num = ost->soc_info->num_channels;
>> +
>> +    for (i = 0; i < ost->clocks->num; i++) {
>> +        ret = ingenic_ost_register_clock(ost, i, 
>> &ingenic_ost_clk_info[i], ost->clocks);
>> +        if (ret) {
>> +            pr_crit("%s: Cannot register clock %d\n", __func__, i);
>> +            goto err_unregister_ost_clocks;
>> +        }
>> +    }
>> +
>> +    ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, 
>> ost->clocks);
>> +    if (ret) {
>> +        pr_crit("%s: Cannot add OF clock provider\n", __func__);
>> +        goto err_unregister_ost_clocks;
>> +    }
>> +
>> +    ost->percpu_timer_channel = OST_CLK_PERCPU_TIMER;
>> +    ost->global_timer_channel = OST_CLK_GLOBAL_TIMER;
>
> If that's a constant, just use the constant where 
> 'ost->percpu_timer_channel' and 'ost->global_timer_channel' are used, 
> I think.
>

Sure.


>> +
>> +    ingenic_ost = ost;
>> +
>> +    return 0;
>> +
>> +err_unregister_ost_clocks:
>> +    for (i = 0; i < ost->clocks->num; i++)
>> +        if (ost->clocks->hws[i])
>> +            clk_hw_unregister(ost->clocks->hws[i]);
>> +    kfree(ost->clocks);
>> +err_clk_disable:
>> +    clk_disable_unprepare(ost->clk);
>> +err_put_clk:
>> +    clk_put(ost->clk);
>> +err_free_ost:
>> +    kfree(ost);
>> +    return ret;
>> +}
>> +
>> +static int __init ingenic_ost_init(struct device_node *np)
>> +{
>> +    unsigned long rate;
>> +    int ret = ingenic_ost_probe(np);
>
> Don't call functions in variable declarations - they can be overlooked 
> easily.
>

OK


>> +
>> +    if (ret)
>> +        pr_crit("%s: Failed to initialize OST clocks: %d\n", 
>> __func__, ret);
>
> return ret?
>

I'll add it in the next version.


>> +
>> +    of_node_clear_flag(np, OF_POPULATED);
>> +
>> +    ret = ingenic_ost_global_timer_init(np, ingenic_ost);
>
> The 'ingenic_ost' variable is just a dirty workaround for the 
> sched_clock callback, which does not take any parameter. Avoid using 
> it here. Make ingenic_ost_probe() return a pointer to your ingenic_ost 
> instance (and a PTR_ERR() on error), and use that pointer for the rest.
>

Sure.

Thanks and best regards!


> Cheers,
> -Paul
>
>> +    if (ret) {
>> +        pr_crit("%s: Unable to init global timer: %x\n", __func__, 
>> ret);
>> +        goto err_free_ingenic_ost;
>> +    }
>> +
>> +    ret = ingenic_ost_percpu_timer_init(np, ingenic_ost);
>> +    if (ret)
>> +        goto err_ost_global_timer_cleanup;
>> +
>> +    /* Register the sched_clock at the end as there's no way to undo 
>> it */
>> +    rate = clk_get_rate(ingenic_ost->global_timer_clk);
>> +    sched_clock_register(ingenic_ost_global_timer_read_cntl, 32, rate);
>> +
>> +    return 0;
>> +
>> +err_ost_global_timer_cleanup:
>> +    clocksource_unregister(&ingenic_ost->cs);
>> +    clk_disable_unprepare(ingenic_ost->global_timer_clk);
>> +    clk_put(ingenic_ost->global_timer_clk);
>> +err_free_ingenic_ost:
>> +    kfree(ingenic_ost);
>> +    return ret;
>> +}
>> +
>> +TIMER_OF_DECLARE(x1000_ost,  "ingenic,x1000-ost", ingenic_ost_init);
>> -- 
>> 2.11.0
>>
>

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