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Message-ID: <20140312035954.GB4706@localhost.localdomain>
Date: Wed, 12 Mar 2014 11:59:54 +0800
From: Chenhui Zhao <chenhui.zhao@...escale.com>
To: Scott Wood <scottwood@...escale.com>
CC: <linuxppc-dev@...ts.ozlabs.org>, <linux-kernel@...r.kernel.org>,
<leoli@...escale.com>, <Jason.Jin@...escale.com>
Subject: Re: [PATCH 3/9] powerpc/rcpm: add RCPM driver
On Tue, Mar 11, 2014 at 06:42:51PM -0500, Scott Wood wrote:
> On Fri, 2014-03-07 at 12:57 +0800, Chenhui Zhao wrote:
> > diff --git a/arch/powerpc/platforms/85xx/corenet_generic.c b/arch/powerpc/platforms/85xx/corenet_generic.c
> > index b756f3d..3fdf9f3 100644
> > --- a/arch/powerpc/platforms/85xx/corenet_generic.c
> > +++ b/arch/powerpc/platforms/85xx/corenet_generic.c
> > @@ -56,6 +56,8 @@ void __init corenet_gen_setup_arch(void)
> >
> > swiotlb_detect_4g();
> >
> > + fsl_rcpm_init();
> > +
> > pr_info("%s board from Freescale Semiconductor\n", ppc_md.name);
>
> RCPM is not board-specific. Why is this in board code?
Init the RCPM driver in the early stage before smp_init(). Because
the time base sync calls a callback function .freeze_time_base()
in the RCPM driver.
Will use early_initcall() instead.
>
> > +static void rcpm_v1_cpu_enter_state(int cpu, int state)
> > +{
> > + unsigned int hw_cpu = get_hard_smp_processor_id(cpu);
> > + unsigned int mask = 1 << hw_cpu;
> > +
> > + switch (state) {
> > + case E500_PM_PH10:
> > + setbits32(&rcpm_v1_regs->cdozcr, mask);
> > + break;
> > + case E500_PM_PH15:
> > + setbits32(&rcpm_v1_regs->cnapcr, mask);
> > + break;
> > + default:
> > + pr_err("Unknown cpu PM state\n");
> > + break;
> > + }
> > +}
>
> Put __func__ in error messages -- and for "unknown value" type messages,
> print the value.
OK.
>
>
> > +static int rcpm_v1_plat_enter_state(int state)
> > +{
> > + u32 *pmcsr_reg = &rcpm_v1_regs->powmgtcsr;
> > + int ret = 0;
> > + int result;
> > +
> > + switch (state) {
> > + case PLAT_PM_SLEEP:
> > + setbits32(pmcsr_reg, RCPM_POWMGTCSR_SLP);
> > +
> > + /* At this point, the device is in sleep mode. */
> > +
> > + /* Upon resume, wait for RCPM_POWMGTCSR_SLP bit to be clear. */
> > + result = spin_event_timeout(
> > + !(in_be32(pmcsr_reg) & RCPM_POWMGTCSR_SLP), 10000, 10);
> > + if (!result) {
> > + pr_err("%s: timeout waiting for SLP bit to be cleared\n",
> > + __func__);
>
> Why are you indenting continuation lines with only two spaces (and yet
> still not aligning with anything)?
Will align with the previous parenthesis.
>
> > + ret = -ETIMEDOUT;
> > + }
> > + break;
> > + default:
> > + pr_err("Unsupported platform PM state\n");
> > + ret = -EINVAL;
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +static void rcpm_v1_freeze_time_base(int freeze)
> > +{
> > + u32 *tben_reg = &rcpm_v1_regs->ctbenr;
> > + static u32 mask;
> > +
> > + if (freeze) {
> > + mask = in_be32(tben_reg);
> > + clrbits32(tben_reg, mask);
> > + } else {
> > + setbits32(tben_reg, mask);
> > + }
> > +
> > + /* read back to push the previous write */
> > + in_be32(tben_reg);
> > +}
> > +
> > +static void rcpm_v2_freeze_time_base(int freeze)
> > +{
> > + u32 *tben_reg = &rcpm_v2_regs->pctbenr;
> > + static u32 mask;
> > +
> > + if (freeze) {
> > + mask = in_be32(tben_reg);
> > + clrbits32(tben_reg, mask);
> > + } else {
> > + setbits32(tben_reg, mask);
> > + }
> > +
> > + /* read back to push the previous write */
> > + in_be32(tben_reg);
> > +}
>
> It looks like the only difference between these two functions is how you
> calculate tben_reg -- factor the rest out into a single function.
Yes. Will factor them out into a single function.
>
> > +int fsl_rcpm_init(void)
> > +{
> > + struct device_node *np;
> > +
> > + np = of_find_compatible_node(NULL, NULL, "fsl,qoriq-rcpm-2.0");
> > + if (np) {
> > + rcpm_v2_regs = of_iomap(np, 0);
> > + of_node_put(np);
> > + if (!rcpm_v2_regs)
> > + return -ENOMEM;
> > +
> > + qoriq_pm_ops = &qoriq_rcpm_v2_ops;
> > +
> > + } else {
> > + np = of_find_compatible_node(NULL, NULL, "fsl,qoriq-rcpm-1.0");
> > + if (np) {
> > + rcpm_v1_regs = of_iomap(np, 0);
> > + of_node_put(np);
> > + if (!rcpm_v1_regs)
> > + return -ENOMEM;
> > +
> > + qoriq_pm_ops = &qoriq_rcpm_v1_ops;
> > +
> > + } else {
> > + pr_err("%s: can't find the rcpm node.\n", __func__);
> > + return -EINVAL;
> > + }
> > + }
> > +
> > + return 0;
> > +}
>
> Why isn't this a proper platform driver?
>
> -Scott
The RCPM is not a single function IP block, instead it is a collection
of device run control and power management. It would be called by other
drivers and functions. For example, the callback .freeze_time_base()
need to be called at early stage of kernel init. Therefore, it would be
better to init it at early stage.
-Chenhui
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