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Message-ID: <20150706213210.GB20866@codeaurora.org>
Date: Mon, 6 Jul 2015 14:32:10 -0700
From: Stephen Boyd <sboyd@...eaurora.org>
To: Boris Brezillon <boris.brezillon@...e-electrons.com>
Cc: Mike Turquette <mturquette@...libre.com>,
linux-clk@...r.kernel.org, Jonathan Corbet <corbet@....net>,
Tony Lindgren <tony@...mide.com>,
Ralf Baechle <ralf@...ux-mips.org>,
Emilio López <emilio@...pez.com.ar>,
Maxime Ripard <maxime.ripard@...e-electrons.com>,
Tero Kristo <t-kristo@...com>,
Peter De Schrijver <pdeschrijver@...dia.com>,
Prashant Gaikwad <pgaikwad@...dia.com>,
Stephen Warren <swarren@...dotorg.org>,
Thierry Reding <thierry.reding@...il.com>,
Alexandre Courbot <gnurou@...il.com>,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-omap@...r.kernel.org,
linux-mips@...ux-mips.org, linux-tegra@...r.kernel.org
Subject: Re: [PATCH v4] clk: change clk_ops' ->determine_rate() prototype
On 07/06, Boris Brezillon wrote:
> Clock rates are stored in an unsigned long field, but ->determine_rate()
> (which returns a rounded rate from a requested one) returns a long
> value (errors are reported using negative error codes), which can lead
> to long overflow if the clock rate exceed 2Ghz.
>
> Change ->determine_rate() prototype to return 0 or an error code, and pass
> a pointer to a clk_rate_request structure containing the expected target
> rate and the rate constraints imposed by clk users.
>
> The clk_rate_request structure might be extended in the future to contain
> other kind of constraints like the rounding policy, the maximum clock
> inaccuracy or other things that are not yet supported by the CCF
> (power consumption constraints ?).
>
> Signed-off-by: Boris Brezillon <boris.brezillon@...e-electrons.com>
Which files did you compile?
drivers/clk/mmp/clk-mix.c: In function ‘mmp_clk_mix_determine_rate’:
drivers/clk/mmp/clk-mix.c:221:13: error: ‘rate’ undeclared (first use in this function)
>
> diff --git a/arch/arm/mach-omap2/dpll3xxx.c b/arch/arm/mach-omap2/dpll3xxx.c
> index 44e57ec..cd27457 100644
> --- a/arch/arm/mach-omap2/dpll3xxx.c
> +++ b/arch/arm/mach-omap2/dpll3xxx.c
> @@ -462,43 +462,38 @@ void omap3_noncore_dpll_disable(struct clk_hw *hw)
> /**
> * omap3_noncore_dpll_determine_rate - determine rate for a DPLL
> * @hw: pointer to the clock to determine rate for
> - * @rate: target rate for the DPLL
> - * @best_parent_rate: pointer for returning best parent rate
> - * @best_parent_clk: pointer for returning best parent clock
> + * @req: target rate request
> *
> * Determines which DPLL mode to use for reaching a desired target rate.
> * Checks whether the DPLL shall be in bypass or locked mode, and if
> * locked, calculates the M,N values for the DPLL via round-rate.
> - * Returns a positive clock rate with success, negative error value
> - * in failure.
> + * Returns a 0 on success, negative error value in failure.
> */
> -long omap3_noncore_dpll_determine_rate(struct clk_hw *hw, unsigned long rate,
> - unsigned long min_rate,
> - unsigned long max_rate,
> - unsigned long *best_parent_rate,
> - struct clk_hw **best_parent_clk)
> +int omap3_noncore_dpll_determine_rate(struct clk_hw *hw,
> + struct clk_rate_request *req)
> {
> struct clk_hw_omap *clk = to_clk_hw_omap(hw);
> struct dpll_data *dd;
>
> - if (!hw || !rate)
> + if (!hw || !req || !req->rate)
Why do we need to check for req? It shouldn't be NULL.
> return -EINVAL;
>
> dd = clk->dpll_data;
> if (!dd)
> return -EINVAL;
>
> - if (__clk_get_rate(dd->clk_bypass) == rate &&
> + if (__clk_get_rate(dd->clk_bypass) == req->rate &&
> (dd->modes & (1 << DPLL_LOW_POWER_BYPASS))) {
> - *best_parent_clk = __clk_get_hw(dd->clk_bypass);
> + req->best_parent_hw = __clk_get_hw(dd->clk_bypass);
> } else {
> - rate = omap2_dpll_round_rate(hw, rate, best_parent_rate);
> - *best_parent_clk = __clk_get_hw(dd->clk_ref);
> + req->rate = omap2_dpll_round_rate(hw, req->rate,
> + &req->best_parent_rate);
> + req->best_parent_hw = __clk_get_hw(dd->clk_ref);
> }
>
> - *best_parent_rate = rate;
> + req->best_parent_rate = req->rate;
>
> - return rate;
> + return 0;
> }
>
> /**
> diff --git a/arch/arm/mach-omap2/dpll44xx.c b/arch/arm/mach-omap2/dpll44xx.c
> index f231be0..d615571 100644
> --- a/arch/arm/mach-omap2/dpll44xx.c
> +++ b/arch/arm/mach-omap2/dpll44xx.c
> @@ -191,42 +191,36 @@ out:
> /**
> * omap4_dpll_regm4xen_determine_rate - determine rate for a DPLL
> * @hw: pointer to the clock to determine rate for
> - * @rate: target rate for the DPLL
> - * @best_parent_rate: pointer for returning best parent rate
> - * @best_parent_clk: pointer for returning best parent clock
> + * @req: target rate request
> *
> * Determines which DPLL mode to use for reaching a desired rate.
> * Checks whether the DPLL shall be in bypass or locked mode, and if
> * locked, calculates the M,N values for the DPLL via round-rate.
> - * Returns a positive clock rate with success, negative error value
> - * in failure.
> + * Returns 0 on success and a negative error value otherwise.
> */
> -long omap4_dpll_regm4xen_determine_rate(struct clk_hw *hw, unsigned long rate,
> - unsigned long min_rate,
> - unsigned long max_rate,
> - unsigned long *best_parent_rate,
> - struct clk_hw **best_parent_clk)
> +int omap4_dpll_regm4xen_determine_rate(struct clk_hw *hw,
> + struct clk_rate_request *req)
> {
> struct clk_hw_omap *clk = to_clk_hw_omap(hw);
> struct dpll_data *dd;
>
> - if (!hw || !rate)
> + if (!hw || !req || !req->rate)
Same comment here. And why would we care about hw being NULL
either for that matter.
> return -EINVAL;
>
> dd = clk->dpll_data;
> if (!dd)
> return -EINVAL;
>
> - if (__clk_get_rate(dd->clk_bypass) == rate &&
> + if (__clk_get_rate(dd->clk_bypass) == req->rate &&
> (dd->modes & (1 << DPLL_LOW_POWER_BYPASS))) {
> - *best_parent_clk = __clk_get_hw(dd->clk_bypass);
> + req->best_parent_hw = __clk_get_hw(dd->clk_bypass);
> } else {
> - rate = omap4_dpll_regm4xen_round_rate(hw, rate,
> - best_parent_rate);
> - *best_parent_clk = __clk_get_hw(dd->clk_ref);
> + req->rate = omap4_dpll_regm4xen_round_rate(hw, req->rate,
> + &req->best_parent_rate);
> + req->best_parent_hw = __clk_get_hw(dd->clk_ref);
> }
>
> - *best_parent_rate = rate;
> + req->best_parent_rate = req->rate;
>
> - return rate;
> + return 0;
> }
> diff --git a/drivers/clk/hisilicon/clk-hi3620.c b/drivers/clk/hisilicon/clk-hi3620.c
> index 715d34a..e1d72e6 100644
> --- a/drivers/clk/hisilicon/clk-hi3620.c
> +++ b/drivers/clk/hisilicon/clk-hi3620.c
> @@ -294,34 +294,31 @@ static unsigned long mmc_clk_recalc_rate(struct clk_hw *hw,
> }
> }
>
> -static long mmc_clk_determine_rate(struct clk_hw *hw, unsigned long rate,
> - unsigned long min_rate,
> - unsigned long max_rate,
> - unsigned long *best_parent_rate,
> - struct clk_hw **best_parent_p)
> +static int mmc_clk_determine_rate(struct clk_hw *hw,
> + struct clk_rate_request *req)
> {
> struct clk_mmc *mclk = to_mmc(hw);
> - unsigned long best = 0;
>
> - if ((rate <= 13000000) && (mclk->id == HI3620_MMC_CIUCLK1)) {
> - rate = 13000000;
> - best = 26000000;
> - } else if (rate <= 26000000) {
> - rate = 25000000;
> - best = 180000000;
> - } else if (rate <= 52000000) {
> - rate = 50000000;
> - best = 360000000;
> - } else if (rate <= 100000000) {
> - rate = 100000000;
> - best = 720000000;
> + req->best_parent_hw = __clk_get_hw(__clk_get_parent(hw->clk));
> +
Where did this come from? We weren't setting the best_parent_p
pointer before.
> + if ((req->rate <= 13000000) && (mclk->id == HI3620_MMC_CIUCLK1)) {
> + req->rate = 13000000;
> + req->best_parent_rate = 26000000;
> + } else if (req->rate <= 26000000) {
> + req->rate = 25000000;
> + req->best_parent_rate = 180000000;
> + } else if (req->rate <= 52000000) {
> + req->rate = 50000000;
> + req->best_parent_rate = 360000000;
> + } else if (req->rate <= 100000000) {
> + req->rate = 100000000;
> + req->best_parent_rate = 720000000;
> } else {
> /* max is 180M */
> - rate = 180000000;
> - best = 1440000000;
> + req->rate = 180000000;
> + req->best_parent_rate = 1440000000;
> }
> - *best_parent_rate = best;
> - return rate;
> + return 0;
> }
>
> static u32 mmc_clk_delay(u32 val, u32 para, u32 off, u32 len)
> diff --git a/drivers/clk/qcom/clk-pll.c b/drivers/clk/qcom/clk-pll.c
> index 245d506..f8f1d44 100644
> --- a/drivers/clk/qcom/clk-pll.c
> +++ b/drivers/clk/qcom/clk-pll.c
> @@ -135,17 +135,21 @@ struct pll_freq_tbl *find_freq(const struct pll_freq_tbl *f, unsigned long rate)
> return NULL;
> }
>
> -static long
> -clk_pll_determine_rate(struct clk_hw *hw, unsigned long rate,
> - unsigned long min_rate, unsigned long max_rate,
> - unsigned long *p_rate, struct clk_hw **p)
> +static int
> +clk_pll_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
> {
> + struct clk *parent = __clk_get_parent(hw->clk);
> struct clk_pll *pll = to_clk_pll(hw);
> const struct pll_freq_tbl *f;
>
> - f = find_freq(pll->freq_tbl, rate);
> + req->best_parent_hw = __clk_get_hw(parent);
> + req->best_parent_rate = __clk_get_rate(parent);
> +
> + f = find_freq(pll->freq_tbl, req->rate);
> if (!f)
> - return clk_pll_recalc_rate(hw, *p_rate);
> + req->rate = clk_pll_recalc_rate(hw, req->best_parent_rate);
> + else
> + req->rate = f->freq;
>
> return f->freq;
return 0?
--
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