mmc: core: Ensure clocks are always enabled before host interaction

Ensure clocks are always enabled before any interaction with the host controller driver. This makes sure that there is no race between host execution and the core layer turning off clocks in different context with clock gating framework. Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Per Forlin <per.forlin@stericsson.com> Signed-off-by: Chris Ball <cjb@laptop.org>

mmc: core: Ensure clocks are always enabled before host interaction
Ensure clocks are always enabled before any interaction with the host controller driver. This makes sure that there is no race between host execution and the core layer turning off clocks in different context with clock gating framework. Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Per Forlin <per.forlin@stericsson.com> Signed-off-by: Chris Ball <cjb@laptop.org>
Sujit Reddy Thumma · Chris Ball
1 parent b6bf30d912
Showing 5 changed files with 61 additions and 30 deletions Side-by-side Diff
drivers/mmc/core/core.c
drivers/mmc/core/host.h
drivers/mmc/core/sd.c
drivers/mmc/core/sdio_irq.c
include/linux/mmc/host.h
@@ -290,8 +290,11 @@
 static void mmc_pre_req(struct mmc_host *host, struct mmc_request *mrq,
 		 bool is_first_req)
 {
-	if (host->ops->pre_req)
+	if (host->ops->pre_req) {
+		mmc_host_clk_hold(host);
 		host->ops->pre_req(host, mrq, is_first_req);
+		mmc_host_clk_release(host);
+	}
 }
  
 /**
  
@@ -306,8 +309,11 @@
 static void mmc_post_req(struct mmc_host *host, struct mmc_request *mrq,
 			 int err)
 {
-	if (host->ops->post_req)
+	if (host->ops->post_req) {
+		mmc_host_clk_hold(host);
 		host->ops->post_req(host, mrq, err);
+		mmc_host_clk_release(host);
+	}
 }
  
 /**
  
@@ -620,7 +626,9 @@
 		int err;
  
 		host->en_dis_recurs = 1;
+		mmc_host_clk_hold(host);
 		err = host->ops->enable(host);
+		mmc_host_clk_release(host);
 		host->en_dis_recurs = 0;
  
 		if (err) {
  
@@ -640,7 +648,9 @@
 		int err;
  
 		host->en_dis_recurs = 1;
+		mmc_host_clk_hold(host);
 		err = host->ops->disable(host, lazy);
+		mmc_host_clk_release(host);
 		host->en_dis_recurs = 0;
  
 		if (err < 0) {
  
@@ -1203,8 +1213,11 @@
  
 	host->ios.signal_voltage = signal_voltage;
  
-	if (host->ops->start_signal_voltage_switch)
+	if (host->ops->start_signal_voltage_switch) {
+		mmc_host_clk_hold(host);
 		err = host->ops->start_signal_voltage_switch(host, &host->ios);
+		mmc_host_clk_release(host);
+	}
  
 	return err;
 }
@@ -14,27 +14,6 @@
  
 int mmc_register_host_class(void);
 void mmc_unregister_host_class(void);
-
-#ifdef CONFIG_MMC_CLKGATE
-void mmc_host_clk_hold(struct mmc_host *host);
-void mmc_host_clk_release(struct mmc_host *host);
-unsigned int mmc_host_clk_rate(struct mmc_host *host);
-
-#else
-static inline void mmc_host_clk_hold(struct mmc_host *host)
-{
-}
-
-static inline void mmc_host_clk_release(struct mmc_host *host)
-{
-}
-
-static inline unsigned int mmc_host_clk_rate(struct mmc_host *host)
-{
-	return host->ios.clock;
-}
-#endif
-
 void mmc_host_deeper_disable(struct work_struct *work);
  
 #endif
@@ -451,9 +451,11 @@
 	 * information and let the hardware specific code
 	 * return what is possible given the options
 	 */
+	mmc_host_clk_hold(card->host);
 	drive_strength = card->host->ops->select_drive_strength(
 		card->sw_caps.uhs_max_dtr,
 		host_drv_type, card_drv_type);
+	mmc_host_clk_release(card->host);
  
 	err = mmc_sd_switch(card, 1, 2, drive_strength, status);
 	if (err)
  
@@ -660,9 +662,12 @@
 		goto out;
  
 	/* SPI mode doesn't define CMD19 */
-	if (!mmc_host_is_spi(card->host) && card->host->ops->execute_tuning)
+	if (!mmc_host_is_spi(card->host) && card->host->ops->execute_tuning) {
+		mmc_host_clk_hold(card->host);
 		err = card->host->ops->execute_tuning(card->host,
 						      MMC_SEND_TUNING_BLOCK);
+		mmc_host_clk_release(card->host);
+	}
  
 out:
 	kfree(status);
  
@@ -850,8 +855,11 @@
 	if (!reinit) {
 		int ro = -1;
  
-		if (host->ops->get_ro)
+		if (host->ops->get_ro) {
+			mmc_host_clk_hold(card->host);
 			ro = host->ops->get_ro(host);
+			mmc_host_clk_release(card->host);
+		}
  
 		if (ro < 0) {
 			pr_warning("%s: host does not "
  
@@ -967,8 +975,11 @@
 		 * Since initialization is now complete, enable preset
 		 * value registers for UHS-I cards.
 		 */
-		if (host->ops->enable_preset_value)
+		if (host->ops->enable_preset_value) {
+			mmc_host_clk_hold(card->host);
 			host->ops->enable_preset_value(host, true);
+			mmc_host_clk_release(card->host);
+		}
 	} else {
 		/*
 		 * Attempt to change to high-speed (if supported)
  
@@ -1151,8 +1162,11 @@
 		return err;
  
 	/* Disable preset value enable if already set since last time */
-	if (host->ops->enable_preset_value)
+	if (host->ops->enable_preset_value) {
+		mmc_host_clk_hold(host);
 		host->ops->enable_preset_value(host, false);
+		mmc_host_clk_release(host);
+	}
  
 	err = mmc_send_app_op_cond(host, 0, &ocr);
 	if (err)
@@ -146,15 +146,21 @@
 		}
  
 		set_current_state(TASK_INTERRUPTIBLE);
-		if (host->caps & MMC_CAP_SDIO_IRQ)
+		if (host->caps & MMC_CAP_SDIO_IRQ) {
+			mmc_host_clk_hold(host);
 			host->ops->enable_sdio_irq(host, 1);
+			mmc_host_clk_release(host);
+		}
 		if (!kthread_should_stop())
 			schedule_timeout(period);
 		set_current_state(TASK_RUNNING);
 	} while (!kthread_should_stop());
  
-	if (host->caps & MMC_CAP_SDIO_IRQ)
+	if (host->caps & MMC_CAP_SDIO_IRQ) {
+		mmc_host_clk_hold(host);
 		host->ops->enable_sdio_irq(host, 0);
+		mmc_host_clk_release(host);
+	}
  
 	pr_debug("%s: IRQ thread exiting with code %d\n",
 		 mmc_hostname(host), ret);
@@ -444,5 +444,24 @@
 	return !(host->caps2 & MMC_CAP2_BOOTPART_NOACC);
 }
  
+#ifdef CONFIG_MMC_CLKGATE
+void mmc_host_clk_hold(struct mmc_host *host);
+void mmc_host_clk_release(struct mmc_host *host);
+unsigned int mmc_host_clk_rate(struct mmc_host *host);
+
+#else
+static inline void mmc_host_clk_hold(struct mmc_host *host)
+{
+}
+
+static inline void mmc_host_clk_release(struct mmc_host *host)
+{
+}
+
+static inline unsigned int mmc_host_clk_rate(struct mmc_host *host)
+{
+	return host->ios.clock;
+}
+#endif
 #endif /* LINUX_MMC_HOST_H */
...	...	@@ -290,8 +290,11 @@
290	290	static void mmc_pre_req(struct mmc_host host, struct mmc_request mrq,
291	291	bool is_first_req)
292	292	{
293		- if (host->ops->pre_req)
	293	+ if (host->ops->pre_req) {
	294	+ mmc_host_clk_hold(host);
294	295	host->ops->pre_req(host, mrq, is_first_req);
	296	+ mmc_host_clk_release(host);
	297	+ }
295	298	}
296	299
297	300	/**
298	301
...	...	@@ -306,8 +309,11 @@
306	309	static void mmc_post_req(struct mmc_host host, struct mmc_request mrq,
307	310	int err)
308	311	{
309		- if (host->ops->post_req)
	312	+ if (host->ops->post_req) {
	313	+ mmc_host_clk_hold(host);
310	314	host->ops->post_req(host, mrq, err);
	315	+ mmc_host_clk_release(host);
	316	+ }
311	317	}
312	318
313	319	/**
314	320
...	...	@@ -620,7 +626,9 @@
620	626	int err;
621	627
622	628	host->en_dis_recurs = 1;
	629	+ mmc_host_clk_hold(host);
623	630	err = host->ops->enable(host);
	631	+ mmc_host_clk_release(host);
624	632	host->en_dis_recurs = 0;
625	633
626	634	if (err) {
627	635
...	...	@@ -640,7 +648,9 @@
640	648	int err;
641	649
642	650	host->en_dis_recurs = 1;
	651	+ mmc_host_clk_hold(host);
643	652	err = host->ops->disable(host, lazy);
	653	+ mmc_host_clk_release(host);
644	654	host->en_dis_recurs = 0;
645	655
646	656	if (err < 0) {
647	657
...	...	@@ -1203,8 +1213,11 @@
1203	1213
1204	1214	host->ios.signal_voltage = signal_voltage;
1205	1215
1206		- if (host->ops->start_signal_voltage_switch)
	1216	+ if (host->ops->start_signal_voltage_switch) {
	1217	+ mmc_host_clk_hold(host);
1207	1218	err = host->ops->start_signal_voltage_switch(host, &host->ios);
	1219	+ mmc_host_clk_release(host);
	1220	+ }
1208	1221
1209	1222	return err;
1210	1223	}
...	...	@@ -14,27 +14,6 @@
14	14
15	15	int mmc_register_host_class(void);
16	16	void mmc_unregister_host_class(void);
17		-
18		-#ifdef CONFIG_MMC_CLKGATE
19		-void mmc_host_clk_hold(struct mmc_host *host);
20		-void mmc_host_clk_release(struct mmc_host *host);
21		-unsigned int mmc_host_clk_rate(struct mmc_host *host);
22		-
23		-#else
24		-static inline void mmc_host_clk_hold(struct mmc_host *host)
25		-{
26		-}
27		-
28		-static inline void mmc_host_clk_release(struct mmc_host *host)
29		-{
30		-}
31		-
32		-static inline unsigned int mmc_host_clk_rate(struct mmc_host *host)
33		-{
34		- return host->ios.clock;
35		-}
36		-#endif
37		-
38	17	void mmc_host_deeper_disable(struct work_struct *work);
39	18
40	19	#endif
...	...	@@ -451,9 +451,11 @@
451	451	* information and let the hardware specific code
452	452	* return what is possible given the options
453	453	*/
	454	+ mmc_host_clk_hold(card->host);
454	455	drive_strength = card->host->ops->select_drive_strength(
455	456	card->sw_caps.uhs_max_dtr,
456	457	host_drv_type, card_drv_type);
	458	+ mmc_host_clk_release(card->host);
457	459
458	460	err = mmc_sd_switch(card, 1, 2, drive_strength, status);
459	461	if (err)
460	462
...	...	@@ -660,9 +662,12 @@
660	662	goto out;
661	663
662	664	/* SPI mode doesn't define CMD19 */
663		- if (!mmc_host_is_spi(card->host) && card->host->ops->execute_tuning)
	665	+ if (!mmc_host_is_spi(card->host) && card->host->ops->execute_tuning) {
	666	+ mmc_host_clk_hold(card->host);
664	667	err = card->host->ops->execute_tuning(card->host,
665	668	MMC_SEND_TUNING_BLOCK);
	669	+ mmc_host_clk_release(card->host);
	670	+ }
666	671
667	672	out:
668	673	kfree(status);
669	674
...	...	@@ -850,8 +855,11 @@
850	855	if (!reinit) {
851	856	int ro = -1;
852	857
853		- if (host->ops->get_ro)
	858	+ if (host->ops->get_ro) {
	859	+ mmc_host_clk_hold(card->host);
854	860	ro = host->ops->get_ro(host);
	861	+ mmc_host_clk_release(card->host);
	862	+ }
855	863
856	864	if (ro < 0) {
857	865	pr_warning("%s: host does not "
858	866
...	...	@@ -967,8 +975,11 @@
967	975	* Since initialization is now complete, enable preset
968	976	* value registers for UHS-I cards.
969	977	*/
970		- if (host->ops->enable_preset_value)
	978	+ if (host->ops->enable_preset_value) {
	979	+ mmc_host_clk_hold(card->host);
971	980	host->ops->enable_preset_value(host, true);
	981	+ mmc_host_clk_release(card->host);
	982	+ }
972	983	} else {
973	984	/*
974	985	* Attempt to change to high-speed (if supported)
975	986
...	...	@@ -1151,8 +1162,11 @@
1151	1162	return err;
1152	1163
1153	1164	/* Disable preset value enable if already set since last time */
1154		- if (host->ops->enable_preset_value)
	1165	+ if (host->ops->enable_preset_value) {
	1166	+ mmc_host_clk_hold(host);
1155	1167	host->ops->enable_preset_value(host, false);
	1168	+ mmc_host_clk_release(host);
	1169	+ }
1156	1170
1157	1171	err = mmc_send_app_op_cond(host, 0, &ocr);
1158	1172	if (err)
...	...	@@ -146,15 +146,21 @@
146	146	}
147	147
148	148	set_current_state(TASK_INTERRUPTIBLE);
149		- if (host->caps & MMC_CAP_SDIO_IRQ)
	149	+ if (host->caps & MMC_CAP_SDIO_IRQ) {
	150	+ mmc_host_clk_hold(host);
150	151	host->ops->enable_sdio_irq(host, 1);
	152	+ mmc_host_clk_release(host);
	153	+ }
151	154	if (!kthread_should_stop())
152	155	schedule_timeout(period);
153	156	set_current_state(TASK_RUNNING);
154	157	} while (!kthread_should_stop());
155	158
156		- if (host->caps & MMC_CAP_SDIO_IRQ)
	159	+ if (host->caps & MMC_CAP_SDIO_IRQ) {
	160	+ mmc_host_clk_hold(host);
157	161	host->ops->enable_sdio_irq(host, 0);
	162	+ mmc_host_clk_release(host);
	163	+ }
158	164
159	165	pr_debug("%s: IRQ thread exiting with code %d\n",
160	166	mmc_hostname(host), ret);
...	...	@@ -444,5 +444,24 @@
444	444	return !(host->caps2 & MMC_CAP2_BOOTPART_NOACC);
445	445	}
446	446
	447	+#ifdef CONFIG_MMC_CLKGATE
	448	+void mmc_host_clk_hold(struct mmc_host *host);
	449	+void mmc_host_clk_release(struct mmc_host *host);
	450	+unsigned int mmc_host_clk_rate(struct mmc_host *host);
	451	+
	452	+#else
	453	+static inline void mmc_host_clk_hold(struct mmc_host *host)
	454	+{
	455	+}
	456	+
	457	+static inline void mmc_host_clk_release(struct mmc_host *host)
	458	+{
	459	+}
	460	+
	461	+static inline unsigned int mmc_host_clk_rate(struct mmc_host *host)
	462	+{
	463	+ return host->ios.clock;
	464	+}
	465	+#endif
447	466	#endif /* LINUX_MMC_HOST_H */