On 10 October 2014 09:13, Kelvin Cheung <keguang.zhang@xxxxxxxxx> wrote:
Why should we apply this patch and what is it all about ?
That's what this field is used for, please don't leave it empty.
> Signed-off-by: Kelvin Cheung <keguang.zhang@xxxxxxxxx>
> ---
> drivers/cpufreq/Kconfig | 10 ++
> drivers/cpufreq/Makefile | 1 +
> drivers/cpufreq/ls1x-cpufreq.c | 217 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 228 insertions(+)
> create mode 100644 drivers/cpufreq/ls1x-cpufreq.c
>
> diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
> index ffe350f..99464d7 100644
> --- a/drivers/cpufreq/Kconfig
> +++ b/drivers/cpufreq/Kconfig
> @@ -250,6 +250,16 @@ config LOONGSON2_CPUFREQ
>
> If in doubt, say N.
>
> +config LOONGSON1_CPUFREQ
> + tristate "Loongson1 CPUFreq Driver"
> + help
> + This option adds a CPUFreq driver for loongson1 processors which
> + support software configurable cpu frequency.
> +
> + For details, take a look at <file:Documentation/cpu-freq/>.
> +
> + If in doubt, say N.
> +
> endmenu
>
> menu "PowerPC CPU frequency scaling drivers"
> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> index db6d9a2..aca7bd3 100644
> --- a/drivers/cpufreq/Makefile
> +++ b/drivers/cpufreq/Makefile
> @@ -98,6 +98,7 @@ obj-$(CONFIG_CRIS_MACH_ARTPEC3) += cris-artpec3-cpufreq.o
> obj-$(CONFIG_ETRAXFS) += cris-etraxfs-cpufreq.o
> obj-$(CONFIG_IA64_ACPI_CPUFREQ) += ia64-acpi-cpufreq.o
> obj-$(CONFIG_LOONGSON2_CPUFREQ) += loongson2_cpufreq.o
> +obj-$(CONFIG_LOONGSON1_CPUFREQ) += ls1x-cpufreq.o
Why don't name it like loongson1 to maintain consistency ?
> obj-$(CONFIG_SH_CPU_FREQ) += sh-cpufreq.o
> obj-$(CONFIG_SPARC_US2E_CPUFREQ) += sparc-us2e-cpufreq.o
> obj-$(CONFIG_SPARC_US3_CPUFREQ) += sparc-us3-cpufreq.o
> diff --git a/drivers/cpufreq/ls1x-cpufreq.c b/drivers/cpufreq/ls1x-cpufreq.c
> new file mode 100644
> index 0000000..3d9a410
> --- /dev/null
> +++ b/drivers/cpufreq/ls1x-cpufreq.c
> @@ -0,0 +1,217 @@
> +/*
> + * CPU Frequency Scaling for Loongson 1 SoC
> + *
> + * Copyright (C) 2014 Zhang, Keguang <keguang.zhang@xxxxxxxxx>
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/cpu.h>
> +#include <linux/cpufreq.h>
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#include <cpufreq.h>
> +#include <loongson1.h>
Okay, it looks like I have forgotten some of the C basics :)
But wouldn't the above two lines search for this file in <include/*>, unless
you have compiled it with something like -I include/linux ??
And even then I don't think loongson1.h is present there ..
What am I missing ?
> +
> +static struct {
> + struct clk *clk; /* CPU clk */
> + struct clk *mux_clk; /* MUX of CPU clk */
> + struct clk *pll_clk; /* PLL clk */
> + struct clk *osc_clk; /* OSC clk */
> + unsigned int max_freq;
> + unsigned int min_freq;
> + struct cpufreq_frequency_table *freq_tbl;
> +} ls1x_cpufreq;
> +
> +static int ls1x_cpufreq_notifier(struct notifier_block *nb,
> + unsigned long val, void *data)
> +{
> + if (val == CPUFREQ_POSTCHANGE)
> + current_cpu_data.udelay_val = loops_per_jiffy;
> +
> + return NOTIFY_OK;
> +}
Why don't you do this at a single place in mips core instead of every
mips cpufreq driver ?
> +static struct notifier_block ls1x_cpufreq_notifier_block = {
> + .notifier_call = ls1x_cpufreq_notifier
> +};
> +
> +static int ls1x_cpufreq_target(struct cpufreq_policy *policy,
> + unsigned int index)
> +{
> + struct device *dev = get_cpu_device(policy->cpu);
Why don't you just save this pointer initially ? And actually
instead of this you should use pdev->dev for all this prints.
This 'dev' is for CPU0 not for driver.
> + unsigned int old_freq, new_freq;
> +
> + old_freq = policy->cur;
> + new_freq = ls1x_cpufreq.freq_tbl[index].frequency;
> +
> + /*
> + * The procedure of reconfiguring CPU clk is as below.
> + *
> + * - Reparent CPU clk to OSC clk
> + * - Reset CPU clock (very important)
> + * - Reconfigure CPU DIV
> + * - Reparent CPU clk back to CPU DIV clk
> + */
> +
> + dev_dbg(dev, "%u KHz --> %u KHz\n", old_freq, new_freq);
> + clk_set_parent(policy->clk, ls1x_cpufreq.osc_clk);
> + __raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) | RST_CPU_EN | RST_CPU,
> + LS1X_CLK_PLL_DIV);
> + __raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) & ~(RST_CPU_EN | RST_CPU),
> + LS1X_CLK_PLL_DIV);
> + clk_set_rate(ls1x_cpufreq.mux_clk, new_freq * 1000);
> + clk_set_parent(policy->clk, ls1x_cpufreq.mux_clk);
> +
> + return 0;
> +}
> +
> +static int ls1x_cpufreq_init(struct cpufreq_policy *policy)
> +{
> + struct device *dev = get_cpu_device(policy->cpu);
> + struct cpufreq_frequency_table *freq_tbl;
> + unsigned int pll_freq, freq;
> + int steps, i;
> +
> + pll_freq = clk_get_rate(ls1x_cpufreq.pll_clk) / 1000;
> +
> + steps = 1 << DIV_CPU_WIDTH;
> + freq_tbl = kzalloc(sizeof(*freq_tbl) * steps, GFP_KERNEL);
You never free it, right ? Even on module-removal. Also, why don't allocate
it once at probe time only ?
> + if (!freq_tbl) {
> + dev_err(dev, "failed to alloc cpufreq_frequency_table\n");
> + return -ENOMEM;
> + }
> +
> + for (i = 0; i < (steps - 1); i++) {
> + freq = pll_freq / (i + 1);
> + if ((freq < ls1x_cpufreq.min_freq) ||
> + (freq > ls1x_cpufreq.max_freq))
> + freq_tbl[i].frequency = CPUFREQ_ENTRY_INVALID;
> + else
> + freq_tbl[i].frequency = freq;
> + dev_dbg(dev, "cpufreq table: index %d: frequency %d\n", i,
> + freq_tbl[i].frequency);
> + }
> + freq_tbl[i].frequency = CPUFREQ_TABLE_END;
> + ls1x_cpufreq.freq_tbl = freq_tbl;
> +
> + policy->clk = ls1x_cpufreq.clk;
> + return cpufreq_generic_init(policy, ls1x_cpufreq.freq_tbl, 0);
> +}
> +
> +static struct cpufreq_driver ls1x_cpufreq_driver = {
> + .name = "cpufreq-ls1x",
> + .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
> + .verify = cpufreq_generic_frequency_table_verify,
> + .target_index = ls1x_cpufreq_target,
> + .get = cpufreq_generic_get,
> + .init = ls1x_cpufreq_init,
> + .attr = cpufreq_generic_attr,
> +};
> +
> +static int ls1x_cpufreq_remove(struct platform_device *pdev)
> +{
> + cpufreq_unregister_notifier(&ls1x_cpufreq_notifier_block,
> + CPUFREQ_TRANSITION_NOTIFIER);
> + cpufreq_unregister_driver(&ls1x_cpufreq_driver);
> + clk_put(ls1x_cpufreq.osc_clk);
> + clk_put(ls1x_cpufreq.clk);
> +
> + return 0;
> +}
> +
> +static int ls1x_cpufreq_probe(struct platform_device *pdev)
> +{
> + struct plat_ls1x_cpufreq *pdata = pdev->dev.platform_data;
> + struct clk *clk;
> + int ret;
> +
Try this code here:
pdata = NULL;
> + if (!pdata && !pdata->clk_name && !pdata->osc_clk_name) {
And tell me what happens here then. :)
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + clk = clk_get(NULL, pdata->clk_name);
To make life simple, why not use devm_clk_get() here and at other places ?
> + if (IS_ERR(clk)) {
> + dev_err(&pdev->dev, "unable to get %s clock\n",
> + pdata->clk_name);
> + ret = PTR_ERR(clk);
> + goto out;
> + }
> + ls1x_cpufreq.clk = clk;
> +
> + clk = clk_get_parent(clk);
> + if (IS_ERR(clk)) {
> + dev_err(&pdev->dev, "unable to get parent of %s clock\n",
> + __clk_get_name(ls1x_cpufreq.clk));
@Mike: Is it fine to include clk-provider for this?
> + ret = PTR_ERR(clk);
> + goto err_mux;
> + }
> + ls1x_cpufreq.mux_clk = clk;
> +
> + clk = clk_get_parent(clk);
> + if (IS_ERR(clk)) {
> + dev_err(&pdev->dev, "unable to get parent of %s clock\n",
> + __clk_get_name(ls1x_cpufreq.mux_clk));
> + ret = PTR_ERR(clk);
> + goto err_mux;
> + }
> + ls1x_cpufreq.pll_clk = clk;
> +
> + clk = clk_get(NULL, pdata->osc_clk_name);
> + if (IS_ERR(clk)) {
> + dev_err(&pdev->dev, "unable to get %s clock\n",
> + pdata->osc_clk_name);
> + ret = PTR_ERR(clk);
> + goto err_mux;
> + }
> + ls1x_cpufreq.osc_clk = clk;
> +
> + ls1x_cpufreq.max_freq = pdata->max_freq;
> + ls1x_cpufreq.min_freq = pdata->min_freq;
> +
> + ret = cpufreq_register_driver(&ls1x_cpufreq_driver);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to register cpufreq driver: %d\n",
> + ret);
> + goto err_driver;
> + }
> +
> + ret = cpufreq_register_notifier(&ls1x_cpufreq_notifier_block,
> + CPUFREQ_TRANSITION_NOTIFIER);
> +
> + if (!ret)
> + goto out;
> +
> + dev_err(&pdev->dev, "failed to register cpufreq notifier: %d\n", ret);
> +
> + cpufreq_unregister_driver(&ls1x_cpufreq_driver);
> +err_driver:
> + clk_put(ls1x_cpufreq.osc_clk);
> +err_mux:
> + clk_put(ls1x_cpufreq.clk);
> +out:
> + return ret;
> +}
> +
> +static struct platform_driver ls1x_cpufreq_platdrv = {
> + .driver = {
> + .name = "ls1x-cpufreq",
> + .owner = THIS_MODULE,
> + },
> + .probe = ls1x_cpufreq_probe,
> + .remove = ls1x_cpufreq_remove,
> +};
> +
> +module_platform_driver(ls1x_cpufreq_platdrv);
> +
> +MODULE_AUTHOR("Kelvin Cheung <keguang.zhang@xxxxxxxxx>");
> +MODULE_DESCRIPTION("Loongson 1 CPUFreq driver");
> +MODULE_LICENSE("GPL");
> --
> 1.9.1
>
