[PATCH] opp: introduce library for device-specific OPPs

Nishanth Menon [off-list ref] writes:

Andrew Morton had written, on 09/17/2010 02:19 PM, the following:

quoted

On Thu, 16 Sep 2010 20:29:33 -0500
Nishanth Menon [off-list ref] wrote:

[...]

quoted

quoted

+void opp_init_cpufreq_table(struct device *dev,
+			    struct cpufreq_frequency_table **table)
+{
+	struct device_opp *dev_opp;
+	struct opp *opp;
+	struct cpufreq_frequency_table *freq_table;
+	int i = 0;
+
+	dev_opp = find_device_opp(dev);
+	if (IS_ERR(dev_opp)) {
+		pr_warning("%s: unable to find device\n", __func__);
+		return;
+	}
+
+	freq_table = kzalloc(sizeof(struct cpufreq_frequency_table) *
+			     (dev_opp->enabled_opp_count + 1), GFP_ATOMIC);
+	if (!freq_table) {
+		pr_warning("%s: failed to allocate frequency table\n",
+			   __func__);
+		return;
+	}
+
+	list_for_each_entry(opp, &dev_opp->opp_list, node) {
+		if (opp->enabled) {
+			freq_table[i].index = i;
+			freq_table[i].frequency = opp->rate / 1000;
+			i++;
+		}
+	}
+
+	freq_table[i].index = i;
+	freq_table[i].frequency = CPUFREQ_TABLE_END;
+
+	*table = &freq_table[0];
+}

So we're playing with cpufreq internals here but there's no #ifdef
CONFIG_CPUFREQ and there's no Kconfig dependency on cpufreq.  That
needs fixing I think, if only from a reduce-code-bloat perspective.

Thanks and ouch.. Again missing documentation. Apologies.
http://marc.info/?l=linux-arm-kernel&m=128473931626114&w=2

c) Dependency of OPP layer is on CONFIG_PM as certain SOCs such as Texas
Instrument's OMAP support have frameworks to optionally boot at a
certain opp without needing cpufreq.

This is called "mpurate" bootarg parameter in OMAP framework. I will
put this under #ifdef CPUFREQ and provide header coverage for the same
appropriately.

The OPP layer in general is dependent on CONFIG_PM, but the snippit
above is called only by CPUfreq core when CPUfreq is enabled, so at
least that function should be under #ifdef CPUFREQ.

Kevin