Re: [RFC/PATCH 09/12] clk: qcom: Add Krait clock controller driver

[pramod gurav]

On Wed, Jun 25, 2014 at 5:36 AM, Stephen Boyd <sboyd@xxxxxxxxxxxxxx> wrote:
> The Krait CPU clocks are made up of a primary mux and secondary
> mux for each CPU and the L2, controlled via cp15 accessors. For
> Kraits within KPSSv1 each secondary mux accepts a different aux
> source, but on KPSSv2 each secondary mux accepts the same aux
> source.
>
> Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
> ---
>  drivers/clk/qcom/Kconfig    |   9 ++
>  drivers/clk/qcom/Makefile   |   1 +
>  drivers/clk/qcom/krait-cc.c | 366 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 376 insertions(+)
>  create mode 100644 drivers/clk/qcom/krait-cc.c
>
> diff --git a/drivers/clk/qcom/Kconfig b/drivers/clk/qcom/Kconfig
> index 247f042dc110..6f835e406930 100644
> --- a/drivers/clk/qcom/Kconfig
> +++ b/drivers/clk/qcom/Kconfig
> @@ -61,3 +61,12 @@ config KPSS_XCC
>           Support for the Krait ACC and GCC clock controllers. Say Y
>           if you want to support CPU frequency scaling on devices such
>           as MSM8960, APQ8064, etc.
> +
> +config KRAITCC
> +       tristate "Krait Clock Controller"
> +       depends on COMMON_CLK_QCOM
> +       depends on ARM
> +       select KRAIT_L2_ACCESSORS
> +       help
> +         Support for the Krait CPU clocks on Qualcomm devices.
> +         Say Y if you want to support CPU frequency scaling.
> diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
> index bb4666733bd9..e8c7f31916da 100644
> --- a/drivers/clk/qcom/Makefile
> +++ b/drivers/clk/qcom/Makefile
> @@ -18,3 +18,4 @@ obj-$(CONFIG_MSM_MMCC_8960) += mmcc-msm8960.o
>  obj-$(CONFIG_MSM_MMCC_8974) += mmcc-msm8974.o
>  obj-$(CONFIG_KPSS_XCC) += kpss-xcc.o
>  obj-$(CONFIG_QCOM_HFPLL) += hfpll.o
> +obj-$(CONFIG_KRAITCC) += krait-cc.o
> diff --git a/drivers/clk/qcom/krait-cc.c b/drivers/clk/qcom/krait-cc.c
> new file mode 100644
> index 000000000000..4ca9589acfca
> --- /dev/null
> +++ b/drivers/clk/qcom/krait-cc.c
> @@ -0,0 +1,366 @@
> +/* Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/slab.h>
> +
> +#include <asm/smp_plat.h>
> +
> +#include "clk-krait.h"
> +
> +DEFINE_FIXED_DIV_CLK(acpu_aux, 2, "gpll0_vote");
> +
> +static u8 sec_mux_map[] = {
> +       2,
> +       0,
> +};
> +
> +static u8 pri_mux_map[] = {
> +       1,
> +       2,
> +       0,
> +};
> +
> +static int
> +krait_add_div(struct device *dev, int id, const char *s, unsigned offset)
> +{
> +       struct div_clk *div;
> +       struct clk_init_data init = {
> +               .num_parents = 1,
> +               .ops = &clk_ops_div,
> +               .flags = CLK_SET_RATE_PARENT,
> +       };
> +       const char *p_names[1];
> +       struct clk *clk;
> +
> +       div = devm_kzalloc(dev, sizeof(*dev), GFP_KERNEL);
> +       if (!div)
> +               return -ENOMEM;
> +
> +       div->data.div = 2;
> +       div->data.min_div = 2;
> +       div->data.max_div = 2;
> +       div->ops = &clk_div_ops_kpss_div2;
> +       div->mask = 0x3;
> +       div->shift = 6;
> +       div->priv = (void *)(id >= 0);
> +       div->offset = offset;
> +       div->hw.init = &init;
> +
> +       init.name = kasprintf(GFP_KERNEL, "hfpll%s_div", s);
> +       if (!init.name)
> +               return -ENOMEM;
> +
> +       init.parent_names = p_names;
> +       p_names[0] = kasprintf(GFP_KERNEL, "hfpll%s", s);
> +       if (!p_names[0]) {
> +               kfree(init.name);
> +               return -ENOMEM;
> +       }
> +
> +       clk = devm_clk_register(dev, &div->hw);
> +       kfree(p_names[0]);
> +       kfree(init.name);
> +
> +       return PTR_ERR_OR_ZERO(clk);
> +}
> +
> +static int
> +krait_add_sec_mux(struct device *dev, int id, const char *s, unsigned offset,
> +                 bool unique_aux)
> +{
> +       struct mux_clk *mux;
> +       static const char *sec_mux_list[] = {
> +               "acpu_aux",
> +               "qsb",
> +       };
> +       struct clk_init_data init = {
> +               .parent_names = sec_mux_list,
> +               .num_parents = ARRAY_SIZE(sec_mux_list),
> +               .ops = &clk_ops_gen_mux,
> +               .flags = CLK_SET_RATE_PARENT,
> +       };
> +       struct clk *clk;
> +
> +       mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
> +       if (!mux)
> +               return -ENOMEM;
> +
> +       mux->offset = offset;
> +       mux->priv = (void *)(id >= 0);
> +       mux->has_safe_parent = true;
> +       mux->safe_sel = 2;
> +       mux->ops = &clk_mux_ops_kpss;
> +       mux->mask = 0x3;
> +       mux->shift = 2;
> +       mux->parent_map = sec_mux_map;
> +       mux->hw.init = &init;
> +
> +       init.name = kasprintf(GFP_KERNEL, "krait%s_sec_mux", s);
> +       if (!init.name)
> +               return -ENOMEM;
> +
> +       if (unique_aux) {
> +               sec_mux_list[0] = kasprintf(GFP_KERNEL, "acpu%s_aux", s);
> +               if (!sec_mux_list[0]) {
> +                       clk = ERR_PTR(-ENOMEM);
> +                       goto err_aux;
> +               }
> +               pr_info("Parents are %s %s\n", sec_mux_list[0], sec_mux_list[1]);
line over 80 characters.

> +       }
> +
> +       clk = devm_clk_register(dev, &mux->hw);
> +
> +       if (unique_aux)
> +               kfree(sec_mux_list[0]);
> +err_aux:
> +       kfree(init.name);
> +       return PTR_ERR_OR_ZERO(clk);
> +}
> +
> +static struct clk *
> +krait_add_pri_mux(struct device *dev, int id, const char * s, unsigned offset)

Extra space before 's'.

> +{
> +       struct mux_clk *mux;
> +       const char *p_names[3];
> +       struct clk_init_data init = {
> +               .parent_names = p_names,
> +               .num_parents = ARRAY_SIZE(p_names),
> +               .ops = &clk_ops_gen_mux,
> +               .flags = CLK_SET_RATE_PARENT,
> +       };
> +       struct clk *clk;
> +
> +       mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
> +       if (!mux)
> +               return ERR_PTR(-ENOMEM);
> +
> +       mux->has_safe_parent = true;
> +       mux->safe_sel = 0;
> +       mux->ops = &clk_mux_ops_kpss;
> +       mux->mask = 0x3;
> +       mux->shift = 0;
> +       mux->offset = offset;
> +       mux->priv = (void *)(id >= 0);
> +       mux->parent_map = pri_mux_map;
> +       mux->hw.init = &init;
> +
> +       init.name = kasprintf(GFP_KERNEL, "krait%s_pri_mux", s);
> +       if (!init.name)
> +               return ERR_PTR(-ENOMEM);
> +
> +       p_names[0] = kasprintf(GFP_KERNEL, "hfpll%s", s);
> +       if (!p_names[0]) {
> +               clk = ERR_PTR(-ENOMEM);
> +               goto err_p0;
> +       }
> +
> +       p_names[1] = kasprintf(GFP_KERNEL, "hfpll%s_div", s);
> +       if (!p_names[1]) {
> +               clk = ERR_PTR(-ENOMEM);
> +               goto err_p1;
> +       }
> +
> +       p_names[2] = kasprintf(GFP_KERNEL, "krait%s_sec_mux", s);
> +       if (!p_names[2]) {
> +               clk = ERR_PTR(-ENOMEM);
> +               goto err_p2;
> +       }
> +
> +       clk = devm_clk_register(dev, &mux->hw);
> +
> +       kfree(p_names[2]);
> +err_p2:
> +       kfree(p_names[1]);
> +err_p1:
> +       kfree(p_names[0]);
> +err_p0:
> +       kfree(init.name);
> +       return clk;
> +}
> +
> +/* id < 0 for L2, otherwise id == physical CPU number */
> +static struct clk *krait_add_clks(struct device *dev, int id, bool unique_aux)
> +{
> +       int ret;
> +       unsigned offset;
> +       const char *s;
> +       struct clk *clk;
> +
> +       if (id >= 0) {
> +               offset = 0x4501 + (0x1000 * id);
> +               s = kasprintf(GFP_KERNEL, "%d", id);
> +               if (!s)
> +                       return ERR_PTR(-ENOMEM);
> +       } else {
> +               offset = 0x500;
> +               s = "_l2";
> +       }
> +
> +       ret = krait_add_div(dev, id, s, offset);
> +       if (ret) {
> +               clk = ERR_PTR(ret);
> +               goto err;
> +       }
> +
> +       ret = krait_add_sec_mux(dev, id, s, offset, unique_aux);
> +       if (ret) {
> +               clk = ERR_PTR(ret);
> +               goto err;
> +       }
> +
> +       clk = krait_add_pri_mux(dev, id, s, offset);
> +err:
> +       if (id >= 0)
> +               kfree(s);
> +
> +       return clk;
> +}
> +
> +static struct clk *krait_of_get(struct of_phandle_args *clkspec, void *data)
> +{
> +       unsigned int idx = clkspec->args[0];
> +       struct clk **clks = data;
> +
> +       if (idx >= 5) {
> +               pr_err("%s: invalid clock index %d\n", __func__, idx);
> +               return ERR_PTR(-EINVAL);
> +       }
> +
> +       return clks[idx] ? : ERR_PTR(-ENODEV);
> +}
> +
> +static const struct of_device_id krait_cc_match_table[] = {
> +       { .compatible = "qcom,krait-cc-v1", (void *)1UL },
> +       { .compatible = "qcom,krait-cc-v2" },
> +       {}
> +};
> +MODULE_DEVICE_TABLE(of, krait_cc_match_table);
> +
> +static int krait_cc_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       const struct of_device_id *id;
> +       unsigned long cur_rate, aux_rate;
> +       int i, cpu;
> +       struct clk *clk;
> +       struct clk **clks;
> +       struct clk *l2_pri_mux_clk;
> +
> +       id = of_match_device(krait_cc_match_table, &pdev->dev);
> +       if (!id)
> +               return -ENODEV;
> +
> +       /* Rate is 1 because 0 causes problems for __clk_mux_determine_rate */
> +       clk = clk_register_fixed_rate(dev, "qsb", NULL, CLK_IS_ROOT, 1);
> +       if (IS_ERR(clk))
> +               return PTR_ERR(clk);
> +
> +       if (!id->data) {
> +               clk = devm_clk_register(dev, &acpu_aux.hw);
> +               if (IS_ERR(clk))
> +                       return PTR_ERR(clk);
> +       }
> +
> +       /* Krait configurations have at most 4 CPUs and one L2 */
> +       clks = devm_kcalloc(dev, 5, sizeof(*clks), GFP_KERNEL);
> +       if (!clks)
> +               return -ENOMEM;
> +
> +       for_each_possible_cpu(i) {
> +               cpu = cpu_logical_map(i);
> +               clk = krait_add_clks(dev, cpu, id->data);
> +               if (IS_ERR(clk))
> +                       return PTR_ERR(clk);
> +               clks[cpu] = clk;
> +       }
> +
> +       l2_pri_mux_clk = krait_add_clks(dev, -1, id->data);
> +       if (IS_ERR(l2_pri_mux_clk))
> +               return PTR_ERR(l2_pri_mux_clk);
> +       clks[4] = l2_pri_mux_clk;
> +
> +       /*
> +        * We don't want the CPU or L2 clocks to be turned off at late init
> +        * if CPUFREQ or HOTPLUG configs are disabled. So, bump up the
> +        * refcount of these clocks. Any cpufreq/hotplug manager can assume
> +        * that the clocks have already been prepared and enabled by the time
> +        * they take over.
> +        */
> +       for_each_online_cpu(i) {
> +               cpu = cpu_logical_map(i);
> +               clk_prepare_enable(l2_pri_mux_clk);
> +               WARN(clk_prepare_enable(clks[cpu]),
> +                       "Unable to turn on CPU%d clock", cpu);
> +       }
> +
> +       /*
> +        * Force reinit of HFPLLs and muxes to overwrite any potential
> +        * incorrect configuration of HFPLLs and muxes by the bootloader.
> +        * While at it, also make sure the cores are running at known rates
> +        * and print the current rate.
> +        *
> +        * The clocks are set to aux clock rate first to make sure the
> +        * secondary mux is not sourcing off of QSB. The rate is then set to
> +        * two different rates to force a HFPLL reinit under all
> +        * circumstances.
> +        */
> +       cur_rate = clk_get_rate(l2_pri_mux_clk);
> +       aux_rate = 384000000;
> +       if (cur_rate == 1) {
> +               pr_info("L2 @ QSB rate. Forcing new rate.\n");
> +               cur_rate = aux_rate;
> +       }
> +       clk_set_rate(l2_pri_mux_clk, aux_rate);
> +       clk_set_rate(l2_pri_mux_clk, 2);
> +       clk_set_rate(l2_pri_mux_clk, cur_rate);
> +       pr_info("L2 @ %lu KHz\n", clk_get_rate(l2_pri_mux_clk) / 1000);
> +       for_each_possible_cpu(i) {
> +               cpu = cpu_logical_map(i);
> +               clk = clks[cpu];
> +               cur_rate = clk_get_rate(clk);
> +               if (cur_rate == 1) {
> +                       pr_info("CPU%d @ QSB rate. Forcing new rate.\n", i);
> +                       cur_rate = aux_rate;
> +               }
> +               clk_set_rate(clk, aux_rate);
> +               clk_set_rate(clk, 2);
> +               clk_set_rate(clk, cur_rate);
> +               pr_info("CPU%d @ %lu KHz\n", i, clk_get_rate(clk) / 1000);
> +       }
> +
> +       of_clk_add_provider(dev->of_node, krait_of_get, clks);
> +
> +       return 0;
> +}
> +
> +static struct platform_driver krait_cc_driver = {
> +       .probe = krait_cc_probe,
> +       .driver = {
> +               .name = "clock-krait",
> +               .of_match_table = krait_cc_match_table,
> +               .owner = THIS_MODULE,
> +       },
> +};
> +module_platform_driver(krait_cc_driver);
> +
> +MODULE_DESCRIPTION("Krait CPU Clock Driver");
> +MODULE_LICENSE("GPL v2");
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> hosted by The Linux Foundation
>
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-- 
Thanks and Regards
Pramod
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