OMAP2+: PM: init_voltages: handle non compliant bootloaders

Bootloaders should in theory setup a frequency which is enabled in OPP table. However, there can be mismatches, and we should try both going lower in addition to the going higher to find a match if bootloader boots up at a OPP than the kernel thinks it should be allowed. We also sequence the frequency and voltage settings properly. Reported-by: Colin Cross <ccross@google.com> Signed-off-by: Nishanth Menon <nm@ti.com> [vaibhav.bedia@ti.com: Pull in for AM33xx] Signed-off-by: Vaibhav Bedia <vaibhav.bedia@ti.com>

OMAP2+: PM: init_voltages: handle non compliant bootloaders
Bootloaders should in theory setup a frequency which is enabled in OPP table. However, there can be mismatches, and we should try both going lower in addition to the going higher to find a match if bootloader boots up at a OPP than the kernel thinks it should be allowed. We also sequence the frequency and voltage settings properly. Reported-by: Colin Cross <ccross@google.com> Signed-off-by: Nishanth Menon <nm@ti.com> [vaibhav.bedia@ti.com: Pull in for AM33xx] Signed-off-by: Vaibhav Bedia <vaibhav.bedia@ti.com>
Nishanth Menon · Afzal Mohammed
1 parent b2274ddfdf
Showing 1 changed file with 62 additions and 16 deletions Side-by-side Diff
arch/arm/mach-omap2/pm.c
@@ -141,14 +141,10 @@
 	struct voltagedomain *voltdm;
 	struct clk *clk;
 	struct opp *opp;
-	unsigned long freq, bootup_volt;
 	struct device *dev;
+	unsigned long freq_cur, freq_valid, bootup_volt;
+	int ret = -EINVAL;
  
-	if (!vdd_name || !clk_name || !oh_name) {
-		pr_err("%s: invalid parameters\n", __func__);
-		goto exit;
-	}
-
 	dev = omap_device_get_by_hwmod_name(oh_name);
 	if (IS_ERR(dev)) {
 		pr_err("%s: Unable to get dev pointer for hwmod %s\n",
  
  
@@ -169,16 +165,20 @@
 		goto exit;
 	}
  
-	freq = clk->rate;
-	clk_put(clk);
+	freq_cur = clk->rate;
+	freq_valid = freq_cur;
  
 	rcu_read_lock();
-	opp = opp_find_freq_ceil(dev, &freq);
+	opp = opp_find_freq_ceil(dev, &freq_valid);
 	if (IS_ERR(opp)) {
-		rcu_read_unlock();
-		printk(KERN_ERR "%s: unable to find boot up OPP for vdd_%s\n",
-			__func__, vdd_name);
-		goto exit;
+		opp = opp_find_freq_floor(dev, &freq_valid);
+		if (IS_ERR(opp)) {
+			rcu_read_unlock();
+			pr_err("%s: no boot OPP match for %ld on vdd_%s\n",
+				__func__, freq_cur, vdd_name);
+			ret = -ENOENT;
+			goto exit_ck;
+		}
 	}
  
 	bootup_volt = opp_get_voltage(opp);
  
@@ -186,11 +186,57 @@
 	if (!bootup_volt) {
 		pr_err("%s: unable to find voltage corresponding "
 			"to the bootup OPP for vdd_%s\n", __func__, vdd_name);
-		goto exit;
+		ret = -ENOENT;
+		goto exit_ck;
 	}
  
-	voltdm_scale(voltdm, bootup_volt);
-	return 0;
+	/*
+	 * Frequency and Voltage have to be sequenced: if we move from
+	 * a lower frequency to higher frequency, raise voltage, followed by
+	 * frequency, and vice versa. we assume that the voltage at boot
+	 * is the required voltage for the frequency it was set for.
+	 * NOTE:
+	 * we can check the frequency, but there is numerous ways to set
+	 * voltage. We play the safe path and just set the voltage.
+	 */
+
+	if (freq_cur < freq_valid) {
+		ret = voltdm_scale(voltdm, bootup_volt);
+		if (ret) {
+			pr_err("%s: Fail set voltage-%s(f=%ld v=%ld)on vdd%s\n",
+				__func__, vdd_name, freq_valid,
+				bootup_volt, vdd_name);
+			goto exit_ck;
+		}
+	}
+
+	/* Set freq only if there is a difference in freq */
+	if (freq_valid != freq_cur) {
+		ret = clk_set_rate(clk, freq_valid);
+		if (ret) {
+			pr_err("%s: Fail set clk-%s(f=%ld v=%ld)on vdd%s\n",
+				__func__, clk_name, freq_valid,
+				bootup_volt, vdd_name);
+			goto exit_ck;
+		}
+	}
+
+	if (freq_cur >= freq_valid) {
+		ret = voltdm_scale(voltdm, bootup_volt);
+		if (ret) {
+			pr_err("%s: Fail set voltage-%s(f=%ld v=%ld)on vdd%s\n",
+				__func__, clk_name, freq_valid,
+				bootup_volt, vdd_name);
+			goto exit_ck;
+		}
+	}
+
+	ret = 0;
+exit_ck:
+	clk_put(clk);
+
+	if (!ret)
+		return 0;
  
 exit:
 	pr_err("%s: unable to set vdd_%s\n", __func__, vdd_name);
...	...	@@ -141,14 +141,10 @@
141	141	struct voltagedomain *voltdm;
142	142	struct clk *clk;
143	143	struct opp *opp;
144		- unsigned long freq, bootup_volt;
145	144	struct device *dev;
	145	+ unsigned long freq_cur, freq_valid, bootup_volt;
	146	+ int ret = -EINVAL;
146	147
147		- if (!vdd_name \|\| !clk_name \|\| !oh_name) {
148		- pr_err("%s: invalid parameters\n", __func__);
149		- goto exit;
150		- }
151		-
152	148	dev = omap_device_get_by_hwmod_name(oh_name);
153	149	if (IS_ERR(dev)) {
154	150	pr_err("%s: Unable to get dev pointer for hwmod %s\n",
155	151
156	152
...	...	@@ -169,16 +165,20 @@
169	165	goto exit;
170	166	}
171	167
172		- freq = clk->rate;
173		- clk_put(clk);
	168	+ freq_cur = clk->rate;
	169	+ freq_valid = freq_cur;
174	170
175	171	rcu_read_lock();
176		- opp = opp_find_freq_ceil(dev, &freq);
	172	+ opp = opp_find_freq_ceil(dev, &freq_valid);
177	173	if (IS_ERR(opp)) {
178		- rcu_read_unlock();
179		- printk(KERN_ERR "%s: unable to find boot up OPP for vdd_%s\n",
180		- __func__, vdd_name);
181		- goto exit;
	174	+ opp = opp_find_freq_floor(dev, &freq_valid);
	175	+ if (IS_ERR(opp)) {
	176	+ rcu_read_unlock();
	177	+ pr_err("%s: no boot OPP match for %ld on vdd_%s\n",
	178	+ __func__, freq_cur, vdd_name);
	179	+ ret = -ENOENT;
	180	+ goto exit_ck;
	181	+ }
182	182	}
183	183
184	184	bootup_volt = opp_get_voltage(opp);
185	185
...	...	@@ -186,11 +186,57 @@
186	186	if (!bootup_volt) {
187	187	pr_err("%s: unable to find voltage corresponding "
188	188	"to the bootup OPP for vdd_%s\n", __func__, vdd_name);
189		- goto exit;
	189	+ ret = -ENOENT;
	190	+ goto exit_ck;
190	191	}
191	192
192		- voltdm_scale(voltdm, bootup_volt);
193		- return 0;
	193	+ /*
	194	+ * Frequency and Voltage have to be sequenced: if we move from
	195	+ * a lower frequency to higher frequency, raise voltage, followed by
	196	+ * frequency, and vice versa. we assume that the voltage at boot
	197	+ * is the required voltage for the frequency it was set for.
	198	+ * NOTE:
	199	+ * we can check the frequency, but there is numerous ways to set
	200	+ * voltage. We play the safe path and just set the voltage.
	201	+ */
	202	+
	203	+ if (freq_cur < freq_valid) {
	204	+ ret = voltdm_scale(voltdm, bootup_volt);
	205	+ if (ret) {
	206	+ pr_err("%s: Fail set voltage-%s(f=%ld v=%ld)on vdd%s\n",
	207	+ __func__, vdd_name, freq_valid,
	208	+ bootup_volt, vdd_name);
	209	+ goto exit_ck;
	210	+ }
	211	+ }
	212	+
	213	+ /* Set freq only if there is a difference in freq */
	214	+ if (freq_valid != freq_cur) {
	215	+ ret = clk_set_rate(clk, freq_valid);
	216	+ if (ret) {
	217	+ pr_err("%s: Fail set clk-%s(f=%ld v=%ld)on vdd%s\n",
	218	+ __func__, clk_name, freq_valid,
	219	+ bootup_volt, vdd_name);
	220	+ goto exit_ck;
	221	+ }
	222	+ }
	223	+
	224	+ if (freq_cur >= freq_valid) {
	225	+ ret = voltdm_scale(voltdm, bootup_volt);
	226	+ if (ret) {
	227	+ pr_err("%s: Fail set voltage-%s(f=%ld v=%ld)on vdd%s\n",
	228	+ __func__, clk_name, freq_valid,
	229	+ bootup_volt, vdd_name);
	230	+ goto exit_ck;
	231	+ }
	232	+ }
	233	+
	234	+ ret = 0;
	235	+exit_ck:
	236	+ clk_put(clk);
	237	+
	238	+ if (!ret)
	239	+ return 0;
194	240
195	241	exit:
196	242	pr_err("%s: unable to set vdd_%s\n", __func__, vdd_name);