omap cpufreq driver in multi-platform kernels
Nishanth Menon
nm at ti.com
Wed Mar 27 09:32:20 EDT 2013
On 02:23-20130327, Paul Walmsley wrote:
> Hi
>
> On Tue, 26 Mar 2013, Rob Herring wrote:
>
> > The omap cpufreq driver causes problems in multi-platform kernels
> > because it unconditionally registers with the cpufreq core and does not
> > check sufficiently that it is running on an omap platform. So on a
> > kernel with highbank and omap drivers booted on highbank, the
> > cpufreq-cpu0 driver fails to init. Any suggestions for how to fix? For
> > DT this could just be several of_machine_is_compatible checks, but I'm
> > not really sure for non-DT. Converting the driver to a platform driver
> > would be another option.
>
> We could move the
>
> mpu_clk = clk_get(NULL, "cpufreq_ck");
>
> down to omap_cpufreq_init(), and bail out early if the clock alias doesn't
> exist. (Presumably we'd also want to change the clock role name if we did
> that, to something like "omap_cpufreq_ck".)
>
> Experimental patch follows, comments welcome.
We should deprecate usage on omap-cpufreq driver eventually, instead go
towards embracing the SoC generic implementation of cpufreq-cpu0 driver
IMHO.
http://marc.info/?l=linux-omap&m=136371580826031&w=2
is the series to support cpufreq_cpu0 driver in DT based boot.
Would you think this approach is sane?
>
>
> - Paul
>
> From c1b4374d9cdcf59e0cbe93aa5a23335cb3e60798 Mon Sep 17 00:00:00 2001
> From: Paul Walmsley <paul at pwsan.com>
> Date: Tue, 26 Mar 2013 20:16:39 -0600
> Subject: [PATCH] EXPERIMENTAL: cpufreq: avoid loading the OMAP driver on
> non-OMAP multiplatform targets
>
> etc. etc.
> ---
> arch/arm/mach-omap2/cclock2420_data.c | 2 +-
> arch/arm/mach-omap2/cclock2430_data.c | 2 +-
> arch/arm/mach-omap2/cclock3xxx_data.c | 2 +-
> arch/arm/mach-omap2/cclock44xx_data.c | 2 +-
> drivers/cpufreq/omap-cpufreq.c | 8 ++++----
> 5 files changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/cclock2420_data.c b/arch/arm/mach-omap2/cclock2420_data.c
> index 0f0a97c..d4316e9 100644
> --- a/arch/arm/mach-omap2/cclock2420_data.c
> +++ b/arch/arm/mach-omap2/cclock2420_data.c
> @@ -1885,7 +1885,7 @@ static struct omap_clk omap2420_clks[] = {
> CLK(NULL, "timer_32k_ck", &func_32k_ck, CK_242X),
> CLK(NULL, "timer_sys_ck", &sys_ck, CK_242X),
> CLK(NULL, "timer_ext_ck", &alt_ck, CK_242X),
> - CLK(NULL, "cpufreq_ck", &virt_prcm_set, CK_242X),
> + CLK(NULL, "omap_cpufreq_ck", &virt_prcm_set, CK_242X),
> };
>
>
> diff --git a/arch/arm/mach-omap2/cclock2430_data.c b/arch/arm/mach-omap2/cclock2430_data.c
> index aed8f74..7c855b9 100644
> --- a/arch/arm/mach-omap2/cclock2430_data.c
> +++ b/arch/arm/mach-omap2/cclock2430_data.c
> @@ -2001,7 +2001,7 @@ static struct omap_clk omap2430_clks[] = {
> CLK(NULL, "timer_32k_ck", &func_32k_ck, CK_243X),
> CLK(NULL, "timer_sys_ck", &sys_ck, CK_243X),
> CLK(NULL, "timer_ext_ck", &alt_ck, CK_243X),
> - CLK(NULL, "cpufreq_ck", &virt_prcm_set, CK_243X),
> + CLK(NULL, "omap_cpufreq_ck", &virt_prcm_set, CK_243X),
> };
>
> static const char *enable_init_clks[] = {
> diff --git a/arch/arm/mach-omap2/cclock3xxx_data.c b/arch/arm/mach-omap2/cclock3xxx_data.c
> index 4579c3c..17dd82c 100644
> --- a/arch/arm/mach-omap2/cclock3xxx_data.c
> +++ b/arch/arm/mach-omap2/cclock3xxx_data.c
> @@ -3501,7 +3501,7 @@ static struct omap_clk omap3xxx_clks[] = {
> CLK(NULL, "uart4_ick", &uart4_ick_am35xx, CK_AM35XX),
> CLK(NULL, "timer_32k_ck", &omap_32k_fck, CK_3XXX),
> CLK(NULL, "timer_sys_ck", &sys_ck, CK_3XXX),
> - CLK(NULL, "cpufreq_ck", &dpll1_ck, CK_3XXX),
> + CLK(NULL, "omap_cpufreq_ck", &dpll1_ck, CK_3XXX),
> };
>
> static const char *enable_init_clks[] = {
> diff --git a/arch/arm/mach-omap2/cclock44xx_data.c b/arch/arm/mach-omap2/cclock44xx_data.c
> index 3d58f33..66b85e5 100644
> --- a/arch/arm/mach-omap2/cclock44xx_data.c
> +++ b/arch/arm/mach-omap2/cclock44xx_data.c
> @@ -1660,7 +1660,7 @@ static struct omap_clk omap44xx_clks[] = {
> CLK("4013a000.timer", "timer_sys_ck", &syc_clk_div_ck, CK_443X),
> CLK("4013c000.timer", "timer_sys_ck", &syc_clk_div_ck, CK_443X),
> CLK("4013e000.timer", "timer_sys_ck", &syc_clk_div_ck, CK_443X),
> - CLK(NULL, "cpufreq_ck", &dpll_mpu_ck, CK_443X),
> + CLK(NULL, "omap_cpufreq_ck", &dpll_mpu_ck, CK_443X),
> };
>
> int __init omap4xxx_clk_init(void)
> diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
> index 9128c07..d46caa5 100644
> --- a/drivers/cpufreq/omap-cpufreq.c
> +++ b/drivers/cpufreq/omap-cpufreq.c
> @@ -175,10 +175,6 @@ static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
> {
> int result = 0;
>
> - mpu_clk = clk_get(NULL, "cpufreq_ck");
> - if (IS_ERR(mpu_clk))
> - return PTR_ERR(mpu_clk);
> -
> if (policy->cpu >= NR_CPUS) {
> result = -EINVAL;
> goto fail_ck;
> @@ -254,6 +250,10 @@ static struct cpufreq_driver omap_driver = {
>
> static int __init omap_cpufreq_init(void)
> {
> + mpu_clk = clk_get(NULL, "omap_cpufreq_ck");
> + if (IS_ERR(mpu_clk))
> + return PTR_ERR(mpu_clk);
> +
> mpu_dev = get_cpu_device(0);
> if (!mpu_dev) {
> pr_warning("%s: unable to get the mpu device\n", __func__);
> --
> 1.7.10.4
>
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--
Regards,
Nishanth Menon
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