Date:   Wed, 30 Sep 2020 16:40:05 +0300
From:   Abel Vesa <abel.vesa@....com>
To:     Dong Aisheng <dongas86@...il.com>
Cc:     Mike Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, Rob Herring <robh@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <kernel@...gutronix.de>,
        Fabio Estevam <fabio.estevam@....com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Anson Huang <anson.huang@....com>,
        Jacky Bai <ping.bai@....com>, Peng Fan <peng.fan@....com>,
        Dong Aisheng <aisheng.dong@....com>,
        Fugang Duan <fugang.duan@....com>,
        devicetree <devicetree@...r.kernel.org>,
        NXP Linux Team <linux-imx@....com>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-clk <linux-clk@...r.kernel.org>
Subject: Re: [PATCH v3 10/14] clk: imx: Add generic blk-ctl driver

On 20-09-11 17:36:06, Dong Aisheng wrote:
> On Tue, Sep 8, 2020 at 6:27 PM Abel Vesa <abel.vesa@....com> wrote:
> >
> > The i.MX8MP platform introduces a new type of IP which is called BLK_CTL in
> > RM and usually is comprised of some GPRs that are considered too
> > generic to be part of any dedicated IP from that specific subsystem.
> >
> > In general, some of the GPRs have some clock bits, some have reset bits,
> > so in order to be able to use the imx clock API, this needs to be
> > in a clock driver. From there it can use the reset controller API and
> > leave the rest to the syscon.
> >
> > Signed-off-by: Abel Vesa <abel.vesa@....com>
> > ---
> >  drivers/clk/imx/Makefile      |   2 +-
> >  drivers/clk/imx/clk-blk-ctl.c | 297 ++++++++++++++++++++++++++++++++++++++++++
> >  drivers/clk/imx/clk-blk-ctl.h |  80 ++++++++++++
> >  3 files changed, 378 insertions(+), 1 deletion(-)
> >  create mode 100644 drivers/clk/imx/clk-blk-ctl.c
> >  create mode 100644 drivers/clk/imx/clk-blk-ctl.h
> >
> > diff --git a/drivers/clk/imx/Makefile b/drivers/clk/imx/Makefile
> > index 79e53f2..105c117 100644
> > --- a/drivers/clk/imx/Makefile
> > +++ b/drivers/clk/imx/Makefile
> > @@ -23,7 +23,7 @@ obj-$(CONFIG_MXC_CLK) += mxc-clk.o
> >
> >  obj-$(CONFIG_CLK_IMX8MM) += clk-imx8mm.o
> >  obj-$(CONFIG_CLK_IMX8MN) += clk-imx8mn.o
> > -obj-$(CONFIG_CLK_IMX8MP) += clk-imx8mp.o
> > +obj-$(CONFIG_CLK_IMX8MP) += clk-imx8mp.o clk-blk-ctl.o
> >  obj-$(CONFIG_CLK_IMX8MQ) += clk-imx8mq.o
> >
> >  obj-$(CONFIG_MXC_CLK_SCU) += clk-imx-scu.o clk-imx-lpcg-scu.o
> > diff --git a/drivers/clk/imx/clk-blk-ctl.c b/drivers/clk/imx/clk-blk-ctl.c
> > new file mode 100644
> > index 00000000..1a6f1eb
> > --- /dev/null
> > +++ b/drivers/clk/imx/clk-blk-ctl.c
> > @@ -0,0 +1,297 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Copyright 2020 NXP.
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/reset-controller.h>
> > +#include <linux/err.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_device.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/pm_runtime.h>
> > +#include <linux/slab.h>
> > +#include <linux/string.h>
> > +#include <linux/types.h>
> > +
> > +#include "clk.h"
> > +#include "clk-blk-ctl.h"
> > +
> > +struct imx_reset_hw {
> > +       u32 offset;
> > +       u32 shift;
> > +       u32 mask;
> > +       volatile unsigned long asserted;
> 
> Could you clarify a bit why need 'volatile' here?
> 

Sorry for the late reply.

Tried something different before sending this version.
Will drop it.

> > +};
> > +
> > +struct imx_pm_safekeep_info {
> > +       uint32_t *regs_values;
> > +       uint32_t *regs_offsets;
> > +       uint32_t regs_num;
> > +};
> > +
> > +struct imx_blk_ctl_drvdata {
> > +       void __iomem *base;
> > +       struct reset_controller_dev rcdev;
> > +       struct imx_reset_hw *rst_hws;
> > +       struct imx_pm_safekeep_info pm_info;
> > +
> > +       spinlock_t lock;
> > +};
> > +
> > +static void __maybe_unused imx_blk_ctl_read_write(struct device *dev,
> > +                                                       bool write)
> > +{
> > +       struct imx_blk_ctl_drvdata *drvdata = dev_get_drvdata(dev);
> > +       struct imx_pm_safekeep_info *pm_info = &drvdata->pm_info;
> > +       void __iomem *base = drvdata->base;
> > +       int i;
> > +
> > +       if (!pm_info->regs_num)
> > +               return;
> > +
> > +       for (i = 0; i < pm_info->regs_num; i++) {
> > +               u32 offset = pm_info->regs_offsets[i];
> > +
> > +               if (write)
> > +                       writel(pm_info->regs_values[i], base + offset);
> > +               else
> > +                       pm_info->regs_values[i] = readl(base + offset);
> > +       }
> > +
> > +}
> > +
> > +static int __maybe_unused imx_blk_ctl_runtime_suspend(struct device *dev)
> > +{
> > +       imx_blk_ctl_read_write(dev, false);
> > +
> > +       return 0;
> > +}
> > +
> > +static int __maybe_unused imx_blk_ctl_runtime_resume(struct device *dev)
> > +{
> > +       imx_blk_ctl_read_write(dev, true);
> > +
> > +       return 0;
> > +}
> > +
> > +const struct dev_pm_ops imx_blk_ctl_pm_ops = {
> > +       SET_RUNTIME_PM_OPS(imx_blk_ctl_runtime_suspend,
> > +                          imx_blk_ctl_runtime_resume, NULL)
> > +       SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> > +                          pm_runtime_force_resume)
> > +};
> > +EXPORT_SYMBOL_GPL(imx_blk_ctl_pm_ops);
> > +
> > +static int imx_blk_ctl_reset_set(struct reset_controller_dev *rcdev,
> > +                                 unsigned long id, bool assert)
> > +{
> > +       struct imx_blk_ctl_drvdata *drvdata = container_of(rcdev,
> > +                       struct imx_blk_ctl_drvdata, rcdev);
> > +       unsigned int offset = drvdata->rst_hws[id].offset;
> > +       unsigned int shift = drvdata->rst_hws[id].shift;
> > +       unsigned int mask = drvdata->rst_hws[id].mask;
> > +       void __iomem *reg_addr = drvdata->base + offset;
> > +       unsigned long flags;
> > +       u32 reg;

As for the, calling deassert first issue, I was thinking maybe we can add
the following here:

	    if (!assert && !test_bit(1, &drvdata->rst_hws[id].asserted))
                    return -ENODEV;

What do you think ?

> > +
> > +       if (assert && !test_and_set_bit(1, &drvdata->rst_hws[id].asserted))
> > +               pm_runtime_get_sync(rcdev->dev);
> > +
> 
> i'm a bit confused because each reset hw has a field 'asserted' which means
> you're doing bit operations on each separate private variable.
> Is that what we want?
> 

Yes, basically, we want to do pm_runtime_get_sync every time
there is a assert request for some specific reset bit only if
that reset bit was not asserted before. That's the purpose of the 'asserted' field.

Same goes for the pm_runtime_put but the condition is reversed.

> BTW, what if user calling deassert first?
> Will that cause writing registers without enabling power domain?
> 
> > +       spin_lock_irqsave(&drvdata->lock, flags);
> > +
> > +       reg = readl(reg_addr);
> > +       if (assert)
> > +               writel(reg & ~(mask << shift), reg_addr);
> > +       else
> > +               writel(reg | (mask << shift), reg_addr);
> > +
> > +       spin_unlock_irqrestore(&drvdata->lock, flags);
> > +
> > +       if (!assert && test_and_clear_bit(1, &drvdata->rst_hws[id].asserted))
> > +               pm_runtime_put(rcdev->dev);
> > +
> > +       return 0;
> > +}
> > +
> > +static int imx_blk_ctl_reset_assert(struct reset_controller_dev *rcdev,
> > +                                          unsigned long id)
> > +{
> > +       return imx_blk_ctl_reset_set(rcdev, id, true);
> > +}
> > +
> > +static int imx_blk_ctl_reset_deassert(struct reset_controller_dev *rcdev,
> > +                                            unsigned long id)
> > +{
> > +       return imx_blk_ctl_reset_set(rcdev, id, false);
> > +}
> > +
> > +static const struct reset_control_ops imx_blk_ctl_reset_ops = {
> > +       .assert         = imx_blk_ctl_reset_assert,
> > +       .deassert       = imx_blk_ctl_reset_deassert,
> > +};
> > +
> > +static int imx_blk_ctl_register_reset_controller(struct device *dev)
> > +{
> > +       const struct imx_blk_ctl_dev_data *dev_data = of_device_get_match_data(dev);
> > +       struct imx_blk_ctl_drvdata *drvdata = dev_get_drvdata(dev);
> > +       int max = dev_data->resets_max;
> > +       struct imx_reset_hw *hws;
> > +       int i;
> > +
> > +       spin_lock_init(&drvdata->lock);
> > +
> > +       drvdata->rcdev.owner     = THIS_MODULE;
> > +       drvdata->rcdev.nr_resets = max;
> > +       drvdata->rcdev.ops       = &imx_blk_ctl_reset_ops;
> > +       drvdata->rcdev.of_node   = dev->of_node;
> > +       drvdata->rcdev.dev       = dev;
> > +
> > +       drvdata->rst_hws = devm_kcalloc(dev, max, sizeof(struct imx_reset_hw),
> > +                                       GFP_KERNEL);
> > +       hws = drvdata->rst_hws;
> > +
> > +       for (i = 0; i < dev_data->hws_num; i++) {
> > +               struct imx_blk_ctl_hw *hw = &dev_data->hws[i];
> > +
> > +               if (hw->type != BLK_CTL_RESET)
> > +                       continue;
> > +
> > +               hws[hw->id].offset = hw->offset;
> > +               hws[hw->id].shift = hw->shift;
> > +               hws[hw->id].mask = hw->mask;
> > +       }
> > +
> > +       return devm_reset_controller_register(dev, &drvdata->rcdev);
> > +}
> > +static struct clk_hw *imx_blk_ctl_register_one_clock(struct device *dev,
> > +                                               struct imx_blk_ctl_hw *hw)
> > +{
> > +       struct imx_blk_ctl_drvdata *drvdata = dev_get_drvdata(dev);
> > +       void __iomem *base = drvdata->base;
> > +       struct clk_hw *clk_hw = NULL;
> > +
> > +       switch (hw->type) {
> > +       case BLK_CTL_CLK_MUX:
> > +               clk_hw = imx_dev_clk_hw_mux_flags(dev, hw->name,
> > +                                                 base + hw->offset,
> > +                                                 hw->shift, hw->width,
> > +                                                 hw->parents,
> > +                                                 hw->parents_count,
> > +                                                 hw->flags);
> > +               break;
> > +       case BLK_CTL_CLK_GATE:
> > +               clk_hw = imx_dev_clk_hw_gate(dev, hw->name, hw->parents,
> > +                                            base + hw->offset, hw->shift);
> > +               break;
> > +       case BLK_CTL_CLK_SHARED_GATE:
> > +               clk_hw = imx_dev_clk_hw_gate_shared(dev, hw->name,
> > +                                                   hw->parents,
> > +                                                   base + hw->offset,
> > +                                                   hw->shift,
> > +                                                   hw->shared_count);
> > +               break;
> > +       case BLK_CTL_CLK_PLL14XX:
> > +               clk_hw = imx_dev_clk_hw_pll14xx(dev, hw->name, hw->parents,
> > +                                               base + hw->offset, hw->pll_tbl);
> > +               break;
> > +       };
> > +
> > +       return clk_hw;
> > +}
> > +
> > +static int imx_blk_ctl_register_clock_controller(struct device *dev)
> > +{
> > +       const struct imx_blk_ctl_dev_data *dev_data = of_device_get_match_data(dev);
> > +       struct clk_hw_onecell_data *clk_hw_data;
> > +       struct clk_hw **hws;
> > +       int i;
> > +
> > +       clk_hw_data = devm_kzalloc(dev, struct_size(clk_hw_data, hws,
> > +                               dev_data->hws_num), GFP_KERNEL);
> > +       if (WARN_ON(!clk_hw_data))
> > +               return -ENOMEM;
> > +
> > +       clk_hw_data->num = dev_data->clocks_max;
> > +       hws = clk_hw_data->hws;
> > +
> > +       for (i = 0; i < dev_data->hws_num; i++) {
> > +               struct imx_blk_ctl_hw *hw = &dev_data->hws[i];
> > +
> > +               hws[hw->id] = imx_blk_ctl_register_one_clock(dev, hw);
> > +               WARN(IS_ERR(hws[hw->id]), "failed to register clock %d", hw->id);
> 
> Is this line duplicated with the following imx_check_clk_hws()?
> 
> Regards
> Aisheng
> 
> > +       }
> > +
> > +       imx_check_clk_hws(hws, dev_data->clocks_max);
> > +
> > +       return of_clk_add_hw_provider(dev->of_node, of_clk_hw_onecell_get,
> > +                                       clk_hw_data);
> > +}
> > +
> > +static int imx_blk_ctl_init_runtime_pm_safekeeping(struct device *dev)
> > +{
> > +       const struct imx_blk_ctl_dev_data *dev_data = of_device_get_match_data(dev);
> > +       struct imx_blk_ctl_drvdata *drvdata = dev_get_drvdata(dev);
> > +       struct imx_pm_safekeep_info *pm_info = &drvdata->pm_info;
> > +       u32 regs_num = dev_data->pm_runtime_saved_regs_num;
> > +       const u32 *regs_offsets = dev_data->pm_runtime_saved_regs;
> > +
> > +       if (!dev_data->pm_runtime_saved_regs_num)
> > +               return 0;
> > +
> > +       pm_info->regs_values = devm_kzalloc(dev,
> > +                                           sizeof(u32) * regs_num,
> > +                                           GFP_KERNEL);
> > +       if (WARN_ON(IS_ERR(pm_info->regs_values)))
> > +               return PTR_ERR(pm_info->regs_values);
> > +
> > +       pm_info->regs_offsets = kmemdup(regs_offsets,
> > +                                       regs_num * sizeof(u32), GFP_KERNEL);
> > +       if (WARN_ON(IS_ERR(pm_info->regs_offsets)))
> > +               return PTR_ERR(pm_info->regs_offsets);
> > +
> > +       pm_info->regs_num = regs_num;
> > +
> > +       return 0;
> > +}
> > +
> > +int imx_blk_ctl_probe(struct platform_device *pdev)
> > +{
> > +       struct imx_blk_ctl_drvdata *drvdata;
> > +       struct device *dev = &pdev->dev;
> > +       int ret;
> > +
> > +       drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
> > +       if (WARN_ON(!drvdata))
> > +               return -ENOMEM;
> > +
> > +       drvdata->base = devm_platform_ioremap_resource(pdev, 0);
> > +       if (WARN_ON(IS_ERR(drvdata->base)))
> > +               return PTR_ERR(drvdata->base);
> > +
> > +       dev_set_drvdata(dev, drvdata);
> > +
> > +       ret = imx_blk_ctl_init_runtime_pm_safekeeping(dev);
> > +       if (ret)
> > +               return ret;
> > +
> > +       pm_runtime_get_noresume(dev);
> > +       pm_runtime_set_active(dev);
> > +       pm_runtime_enable(dev);
> > +
> > +       ret = imx_blk_ctl_register_clock_controller(dev);
> > +       if (ret) {
> > +               pm_runtime_put(dev);
> > +               return ret;
> > +       }
> > +
> > +       ret = imx_blk_ctl_register_reset_controller(dev);
> > +
> > +       pm_runtime_put(dev);
> > +
> > +       return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(imx_blk_ctl_probe);
> > diff --git a/drivers/clk/imx/clk-blk-ctl.h b/drivers/clk/imx/clk-blk-ctl.h
> > new file mode 100644
> > index 00000000..e5bf723
> > --- /dev/null
> > +++ b/drivers/clk/imx/clk-blk-ctl.h
> > @@ -0,0 +1,80 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef __MACH_IMX_CLK_BLK_CTL_H
> > +#define __MACH_IMX_CLK_BLK_CTL_H
> > +
> > +enum imx_blk_ctl_hw_type {
> > +       BLK_CTL_CLK_MUX,
> > +       BLK_CTL_CLK_GATE,
> > +       BLK_CTL_CLK_SHARED_GATE,
> > +       BLK_CTL_CLK_PLL14XX,
> > +       BLK_CTL_RESET,
> > +};
> > +
> > +struct imx_blk_ctl_hw {
> > +       int type;
> > +       char *name;
> > +       u32 offset;
> > +       u32 shift;
> > +       u32 mask;
> > +       u32 width;
> > +       u32 flags;
> > +       u32 id;
> > +       const void *parents;
> > +       u32 parents_count;
> > +       int *shared_count;
> > +       const struct imx_pll14xx_clk *pll_tbl;
> > +};
> > +
> > +struct imx_blk_ctl_dev_data {
> > +       struct imx_blk_ctl_hw *hws;
> > +       u32 hws_num;
> > +
> > +       u32 clocks_max;
> > +       u32 resets_max;
> > +
> > +       u32 pm_runtime_saved_regs_num;
> > +       u32 pm_runtime_saved_regs[];
> > +};
> > +
> > +#define IMX_BLK_CTL(_type, _name, _id, _offset, _shift, _width, _mask, _parents, _parents_count, _flags, sh_count, _pll_tbl) \
> > +       {                                               \
> > +               .type = _type,                          \
> > +               .name = _name,                          \
> > +               .id = _id,                              \
> > +               .offset = _offset,                      \
> > +               .shift = _shift,                        \
> > +               .width = _width,                        \
> > +               .mask = _mask,                          \
> > +               .parents = _parents,                    \
> > +               .parents_count = _parents_count,        \
> > +               .flags = _flags,                        \
> > +               .shared_count = sh_count,               \
> > +               .pll_tbl = _pll_tbl,                    \
> > +       }
> > +
> > +#define IMX_BLK_CTL_CLK_MUX(_name, _id, _offset, _shift, _width, _parents) \
> > +       IMX_BLK_CTL(BLK_CTL_CLK_MUX, _name, _id, _offset, _shift, _width, 0, _parents, ARRAY_SIZE(_parents), 0, NULL, NULL)
> > +
> > +#define IMX_BLK_CTL_CLK_MUX_FLAGS(_name, _id, _offset, _shift, _width, _parents, _flags) \
> > +       IMX_BLK_CTL(BLK_CTL_CLK_MUX, _name, _id, _offset, _shift, _width, 0, _parents, ARRAY_SIZE(_parents), _flags, NULL, NULL)
> > +
> > +#define IMX_BLK_CTL_CLK_GATE(_name, _id, _offset, _shift, _parents) \
> > +       IMX_BLK_CTL(BLK_CTL_CLK_GATE, _name, _id, _offset, _shift, 1, 0, _parents, 1, 0, NULL, NULL)
> > +
> > +#define IMX_BLK_CTL_CLK_SHARED_GATE(_name, _id, _offset, _shift, _parents, sh_count) \
> > +       IMX_BLK_CTL(BLK_CTL_CLK_SHARED_GATE, _name, _id, _offset, _shift, 1, 0, _parents, 1, 0, sh_count, NULL)
> > +
> > +#define IMX_BLK_CTL_CLK_PLL14XX(_name, _id, _offset, _parents, _pll_tbl) \
> > +       IMX_BLK_CTL(BLK_CTL_CLK_PLL14XX, _name, _id, _offset, 0, 0, 0, _parents, 1, 0, NULL, _pll_tbl)
> > +
> > +#define IMX_BLK_CTL_RESET(_id, _offset, _shift) \
> > +       IMX_BLK_CTL(BLK_CTL_RESET, NULL, _id, _offset, _shift, 0, 1, NULL, 0, 0, NULL, NULL)
> > +
> > +#define IMX_BLK_CTL_RESET_MASK(_id, _offset, _shift, mask) \
> > +       IMX_BLK_CTL(BLK_CTL_RESET, NULL, _id, _offset, _shift, 0, mask, NULL, 0, 0, NULL, NULL)
> > +
> > +extern const struct dev_pm_ops imx_blk_ctl_pm_ops;
> > +
> > +int imx_blk_ctl_probe(struct platform_device *pdev);
> > +
> > +#endif
> > --
> > 2.7.4
> >

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