From: Nikolaus Schulz <nikolaus.schulz@avionic-design.de>
To: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: linux-tegra@vger.kernel.org,
Javier Martinez Canillas <javier.martinez@collabora.co.uk>,
mikko.perttunen@kapsi.fi, acourbot@nvidia.com,
Mikko Perttunen <mperttunen@nvidia.com>,
Peter De Schrijver <pdeschrijver@nvidia.com>,
Prashant Gaikwad <pgaikwad@nvidia.com>,
Mike Turquette <mturquette@linaro.org>,
Stephen Warren <swarren@wwwdotorg.org>,
Thierry Reding <thierry.reding@gmail.com>,
Alexandre Courbot <gnurou@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 12/14] clk: tegra: Add EMC clock driver
Date: Wed, 19 Nov 2014 16:29:53 +0100 [thread overview]
Message-ID: <20141119152941.GA26442@avionic-0071.adnet.avionic-design.de> (raw)
In-Reply-To: <1416312860-4446-13-git-send-email-tomeu.vizoso@collabora.com>
On Tue, Nov 18, 2014 at 01:13:14PM +0100, Tomeu Vizoso wrote:
> From: Mikko Perttunen <mperttunen@nvidia.com>
>
> The driver is currently only tested on Tegra124 Jetson TK1, but should
> work with other Tegra124 boards, provided that correct EMC tables are
> provided through the device tree. Older chip models have differing
> timing change sequences, so they are not currently supported.
>
> Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
>
> ---
>
> v5: * Get a pointer to the EMC driver at runtime, to be used when
> calling the EMC API.
> * Misc. style fixes
> * Fix logic for rounding down to a high rate
>
> v4: * Adapt to changes in the OF bindings
> * Improve error handling
> * Fix comment style
> * Make static a few more functions
>
> v3: * Add some locking to protect the registers that are shared with the MC
> clock
>
> v2: * Make sure that the clock is properly registered
> * Bail out early from attempts to set the same rate
> ---
> diff --git a/drivers/clk/tegra/clk-emc.c b/drivers/clk/tegra/clk-emc.c
> new file mode 100644
> index 0000000..399d945
> --- /dev/null
> +++ b/drivers/clk/tegra/clk-emc.c
> @@ -0,0 +1,532 @@
> +/*
> + * Rounds up unless no higher rate exists, in which case down. This way is
> + * safer since things have EMC rate floors. Also don't touch parent_rate
> + * since we don't want the CCF to play with our parent clocks.
> + */
> +static long emc_round_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long *parent_rate)
> +{
> + struct tegra_clk_emc *tegra;
> + u8 ram_code = tegra_read_ram_code();
> + struct emc_timing *timing;
> + int i;
> +
> + tegra = container_of(hw, struct tegra_clk_emc, hw);
> +
> + for (i = 0; i < tegra->num_timings; i++) {
> + timing = tegra->timings + i;
> + if (timing->ram_code != ram_code)
> + continue;
> +
> + if (timing->rate >= rate)
> + return timing->rate;
> + }
> +
> + for (i = tegra->num_timings - 1; i >= 0; i--) {
> + timing = tegra->timings + i;
> + if (timing->ram_code != ram_code)
> + continue;
> +
> + return timing->rate;
> + }
While this is technically not wrong, it could be simplified to something
like
struct emc_timing *timing = NULL;
for (i = 0; i < tegra->num_timings; i++) {
if (tegra->timings[i].ram_code != ram_code)
continue;
timing = tegra->timings + i;
if (timing->rate >= rate)
return timing->rate;
}
if (timing)
return timing->rate;
> +
> + return __clk_get_rate(hw->clk);
> +}
next prev parent reply other threads:[~2014-11-19 15:28 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-18 12:13 [PATCH v5 00/14] Tegra124 EMC (external memory controller) support Tomeu Vizoso
2014-11-18 12:13 ` [PATCH v5 01/14] clk: tegra124: Remove old emc clock Tomeu Vizoso
2014-11-18 21:23 ` Mike Turquette
2014-11-18 12:13 ` [PATCH v5 02/14] of: Document long-ram-code property in nvidia,tegra20-apbmisc Tomeu Vizoso
2014-11-18 12:13 ` [PATCH v5 03/14] soc/tegra: Add ram code reader helper Tomeu Vizoso
2014-11-18 12:13 ` [PATCH v5 04/14] of: document new emc-timings subnode in nvidia,tegra124-car Tomeu Vizoso
2014-11-18 12:13 ` [PATCH v5 05/14] of: Document timings subnode of nvidia,tegra-mc Tomeu Vizoso
2014-11-18 12:13 ` [PATCH v5 06/14] of: Add Tegra124 EMC bindings Tomeu Vizoso
2014-11-18 12:13 ` [PATCH v5 07/14] of: document external-memory-controller property in tegra124-car Tomeu Vizoso
2014-11-18 12:13 ` [PATCH v5 08/14] ARM: tegra: Add EMC to Tegra124 device tree Tomeu Vizoso
2014-11-18 12:13 ` [PATCH v5 09/14] ARM: tegra: Add EMC timings to Jetson TK1 " Tomeu Vizoso
2014-11-18 12:13 ` [PATCH v5 10/14] memory: tegra: Add API needed by the EMC driver Tomeu Vizoso
2014-11-18 12:13 ` [PATCH v5 11/14] memory: tegra: Add EMC (external memory controller) driver Tomeu Vizoso
2014-11-18 12:13 ` [PATCH v5 12/14] clk: tegra: Add EMC clock driver Tomeu Vizoso
2014-11-18 21:33 ` Mike Turquette
2014-11-19 15:29 ` Nikolaus Schulz [this message]
2015-01-02 16:27 ` Peter De Schrijver
2015-01-05 13:59 ` Thierry Reding
2015-03-12 9:30 ` Tomeu Vizoso
2014-11-18 12:13 ` [PATCH v5 13/14] memory: tegra: Add debugfs entry for getting and setting the EMC rate Tomeu Vizoso
2014-11-18 12:13 ` [PATCH v5 14/14] clk: tegra: Set the EMC clock as the parent of the MC clock Tomeu Vizoso
2014-11-18 21:35 ` Mike Turquette
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