Message-ID: <CAOh2x=mQt-GJa8Hc-zybKOKJBhi5jWVy5-UN57pGJDdE1PPx_g@mail.gmail.com>
Date:	Mon, 22 Apr 2013 08:55:35 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Zhao Chenhui <chenhui.zhao@...escale.com>
Cc:	linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 06/15] powerpc/85xx: add support to JOG feature using
 cpufreq interface

On Fri, Apr 19, 2013 at 4:17 PM, Zhao Chenhui
<chenhui.zhao@...escale.com> wrote:
> diff --git a/drivers/cpufreq/mpc85xx-cpufreq.c b/drivers/cpufreq/mpc85xx-cpufreq.c

> +#include <linux/module.h>
> +#include <linux/cpufreq.h>
> +#include <linux/of_platform.h>
> +#include <linux/suspend.h>
> +#include <linux/cpu.h>
> +#include <linux/time.h>
> +#include <linux/io.h>
> +#include <linux/smp.h>

Would be better to keep them in alphabetical order, so that we don't add
anything twice.

> +static int mpc85xx_cpufreq_cpu_init(struct cpufreq_policy *policy)
> +{
> +       unsigned int i, cur_pll;
> +       int hw_cpu = get_hard_smp_processor_id(policy->cpu);
> +
> +       if (!cpu_present(policy->cpu))

This can't happen and so no need to check it.

> +               return -ENODEV;
> +
> +       /* the latency of a transition, the unit is ns */
> +       policy->cpuinfo.transition_latency = 2000;
> +
> +       cur_pll = get_pll(hw_cpu);
> +
> +       /* initialize frequency table */
> +       pr_debug("core%d frequency table:\n", hw_cpu);
> +       for (i = 0; mpc85xx_freqs[i].frequency != CPUFREQ_TABLE_END; i++) {
> +               if (mpc85xx_freqs[i].index <= max_pll[hw_cpu]) {
> +                       /* The frequency unit is kHz. */
> +                       mpc85xx_freqs[i].frequency =
> +                               (sysfreq * mpc85xx_freqs[i].index / 2) / 1000;
> +               } else {
> +                       mpc85xx_freqs[i].frequency = CPUFREQ_ENTRY_INVALID;
> +               }
> +
> +               pr_debug("%d: %dkHz\n", i, mpc85xx_freqs[i].frequency);
> +
> +               if (mpc85xx_freqs[i].index == cur_pll)
> +                       policy->cur = mpc85xx_freqs[i].frequency;
> +       }
> +       pr_debug("current pll is at %d, and core freq is%d\n",
> +                       cur_pll, policy->cur);
> +
> +       cpufreq_frequency_table_get_attr(mpc85xx_freqs, policy->cpu);
> +
> +       /*
> +        * This ensures that policy->cpuinfo_min
> +        * and policy->cpuinfo_max are set correctly.
> +        */
> +       return cpufreq_frequency_table_cpuinfo(policy, mpc85xx_freqs);

Call cpufreq_frequency_table_get_attr() at the end after above call is
successful.

> +}

> +static int mpc85xx_cpufreq_target(struct cpufreq_policy *policy,
> +                             unsigned int target_freq,
> +                             unsigned int relation)

merge above two lines.

> +{
> +       struct cpufreq_freqs freqs;
> +       unsigned int new;
> +       int ret = 0;
> +
> +       if (!set_pll)
> +               return -ENODEV;
> +
> +       cpufreq_frequency_table_target(policy,
> +                                      mpc85xx_freqs,
> +                                      target_freq,
> +                                      relation,
> +                                      &new);

same.. merge all above to put it in a single line.

> +       freqs.old = policy->cur;
> +       freqs.new = mpc85xx_freqs[new].frequency;
> +       freqs.cpu = policy->cpu;

not required now.

> +       mutex_lock(&mpc85xx_switch_mutex);
> +       cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

ditto. Rebase over latest code from linux-next. This call has changed.

> +       ret = set_pll(policy->cpu, mpc85xx_freqs[new].index);
> +       if (!ret) {
> +               pr_info("cpufreq: Setting core%d frequency to %d kHz and PLL ratio to %d:2\n",
> +                        policy->cpu, mpc85xx_freqs[new].frequency,
> +                        mpc85xx_freqs[new].index);
> +
> +               ppc_proc_freq = freqs.new * 1000ul;
> +       }
> +       cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
> +       mutex_unlock(&mpc85xx_switch_mutex);
> +
> +       return ret;
> +}

> +static int __init mpc85xx_jog_init(void)
> +{
> +       struct device_node *np;
> +       unsigned int svr;
> +
> +       np = of_find_matching_node(NULL, mpc85xx_jog_ids);
> +       if (!np)
> +               return -ENODEV;
> +
> +       guts = of_iomap(np, 0);
> +       if (!guts) {
> +               of_node_put(np);
> +               return -ENODEV;
> +       }
> +
> +       sysfreq = fsl_get_sys_freq();
> +
> +       if (of_device_is_compatible(np, "fsl,mpc8536-guts")) {
> +               svr = mfspr(SPRN_SVR);
> +               if ((svr & 0x7fff) == 0x10) {
> +                       pr_err("MPC8536 Rev 1.0 does not support cpufreq(JOG).\n");
> +                       of_node_put(np);

unmap too??

> +                       return -ENODEV;
> +               }
> +               mpc85xx_freqs = mpc8536_freqs_table;
> +               set_pll = mpc8536_set_pll;
> +               max_pll[0] = get_pll(0);
> +
> +       } else if (of_device_is_compatible(np, "fsl,p1022-guts")) {
> +               mpc85xx_freqs = p1022_freqs_table;
> +               set_pll = p1022_set_pll;
> +               max_pll[0] = get_pll(0);
> +               max_pll[1] = get_pll(1);
> +       }
> +
> +       pr_info("Freescale MPC85xx cpufreq(JOG) driver\n");
> +
> +       of_node_put(np);
> +       return cpufreq_register_driver(&mpc85xx_cpufreq_driver);
> +}
> +
> +device_initcall(mpc85xx_jog_init);
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