ALSA: emu10k1: Use workqueue instead of kthread for emu1010 fw polling

This patch is a cleanup of EMU1010 dock probing code in emu10k1 driver
to use work instead of kthread in a loop.  The work is lighter and
easier to control than kthread, in general.

Instead of a loop with the explicit sleep, we do simply
delayed-schedule the work.  At suspend/resume callbacks, the work is
canceled and restarted, respectively.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

include/sound/emu10k1.h

@@ -1688,7 +1688,8 @@ struct snd_emu1010 {
 	unsigned int internal_clock; /* 44100 or 48000 */
 	unsigned int optical_in; /* 0:SPDIF, 1:ADAT */
 	unsigned int optical_out; /* 0:SPDIF, 1:ADAT */
-	struct task_struct *firmware_thread;
+	struct delayed_work firmware_work;
+	u32 last_reg;
 };
 
 struct snd_emu10k1 {

sound/pci/emu10k1/emu10k1.c

@@ -194,6 +194,9 @@ static int snd_card_emu10k1_probe(struct pci_dev *pci,
 	if ((err = snd_card_register(card)) < 0)
 		goto error;
 
+	if (emu->card_capabilities->emu_model)
+		schedule_delayed_work(&emu->emu1010.firmware_work, 0);
+
 	pci_set_drvdata(pci, card);
 	dev++;
 	return 0;
@@ -219,6 +222,8 @@ static int snd_emu10k1_suspend(struct device *dev)
 
 	emu->suspend = 1;
 
+	cancel_delayed_work_sync(&emu->emu1010.firmware_work);
+
 	snd_pcm_suspend_all(emu->pcm);
 	snd_pcm_suspend_all(emu->pcm_mic);
 	snd_pcm_suspend_all(emu->pcm_efx);
@@ -252,6 +257,10 @@ static int snd_emu10k1_resume(struct device *dev)
 	emu->suspend = 0;
 
 	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
+
+	if (emu->card_capabilities->emu_model)
+		schedule_delayed_work(&emu->emu1010.firmware_work, 0);
+
 	return 0;
 }
 

sound/pci/emu10k1/emu10k1_main.c

@@ -32,7 +32,6 @@
  */
 
 #include <linux/sched.h>
-#include <linux/kthread.h>
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/module.h>
@@ -742,21 +741,19 @@ static int snd_emu1010_load_firmware(struct snd_emu10k1 *emu, int dock,
 	return snd_emu1010_load_firmware_entry(emu, *fw);
 }
 
-static int emu1010_firmware_thread(void *data)
+static void emu1010_firmware_work(struct work_struct *work)
 {
-	struct snd_emu10k1 *emu = data;
+	struct snd_emu10k1 *emu;
 	u32 tmp, tmp2, reg;
-	u32 last_reg = 0;
 	int err;
 
-	for (;;) {
-		/* Delay to allow Audio Dock to settle */
-		msleep_interruptible(1000);
-		if (kthread_should_stop())
-			break;
+	emu = container_of(work, struct snd_emu10k1,
+			   emu1010.firmware_work.work);
+	if (emu->card->shutdown)
+		return;
 #ifdef CONFIG_PM_SLEEP
 	if (emu->suspend)
-			continue;
+		return;
 #endif
 	snd_emu1010_fpga_read(emu, EMU_HANA_IRQ_STATUS, &tmp); /* IRQ Status */
 	snd_emu1010_fpga_read(emu, EMU_HANA_OPTION_CARDS, &reg); /* OPTIONS: Which cards are attached to the EMU */
@@ -765,16 +762,16 @@ static int emu1010_firmware_thread(void *data)
 		/* Return to Audio Dock programming mode */
 		dev_info(emu->card->dev,
 			 "emu1010: Loading Audio Dock Firmware\n");
-			snd_emu1010_fpga_write(emu, EMU_HANA_FPGA_CONFIG, EMU_HANA_FPGA_CONFIG_AUDIODOCK);
+		snd_emu1010_fpga_write(emu, EMU_HANA_FPGA_CONFIG,
+				       EMU_HANA_FPGA_CONFIG_AUDIODOCK);
 		err = snd_emu1010_load_firmware(emu, 1, &emu->dock_fw);
 		if (err < 0)
-				continue;
+			goto next;
 
 		snd_emu1010_fpga_write(emu, EMU_HANA_FPGA_CONFIG, 0);
 		snd_emu1010_fpga_read(emu, EMU_HANA_IRQ_STATUS, &tmp);
 		dev_info(emu->card->dev,
-				 "emu1010: EMU_HANA+DOCK_IRQ_STATUS = 0x%x\n",
-				 tmp);
+			 "emu1010: EMU_HANA+DOCK_IRQ_STATUS = 0x%x\n", tmp);
 		/* ID, should read & 0x7f = 0x55 when FPGA programmed. */
 		snd_emu1010_fpga_read(emu, EMU_HANA_ID, &tmp);
 		dev_info(emu->card->dev,
@@ -784,31 +781,30 @@ static int emu1010_firmware_thread(void *data)
 			dev_info(emu->card->dev,
 				 "emu1010: Loading Audio Dock Firmware file failed, reg = 0x%x\n",
 				 tmp);
-				continue;
+			goto next;
 		}
 		dev_info(emu->card->dev,
 			 "emu1010: Audio Dock Firmware loaded\n");
 		snd_emu1010_fpga_read(emu, EMU_DOCK_MAJOR_REV, &tmp);
 		snd_emu1010_fpga_read(emu, EMU_DOCK_MINOR_REV, &tmp2);
-			dev_info(emu->card->dev, "Audio Dock ver: %u.%u\n",
-				   tmp, tmp2);
+		dev_info(emu->card->dev, "Audio Dock ver: %u.%u\n", tmp, tmp2);
 		/* Sync clocking between 1010 and Dock */
 		/* Allow DLL to settle */
 		msleep(10);
 		/* Unmute all. Default is muted after a firmware load */
 		snd_emu1010_fpga_write(emu, EMU_HANA_UNMUTE, EMU_UNMUTE);
-		} else if (!reg && last_reg) {
+	} else if (!reg && emu->emu1010.last_reg) {
 		/* Audio Dock removed */
-			dev_info(emu->card->dev,
-				 "emu1010: Audio Dock detached\n");
+		dev_info(emu->card->dev, "emu1010: Audio Dock detached\n");
 		/* Unmute all */
 		snd_emu1010_fpga_write(emu, EMU_HANA_UNMUTE, EMU_UNMUTE);
 	}
 
-		last_reg = reg;
-	}
-	dev_info(emu->card->dev, "emu1010: firmware thread stopping\n");
-	return 0;
+ next:
+	emu->emu1010.last_reg = reg;
+	if (!emu->card->shutdown)
+		schedule_delayed_work(&emu->emu1010.firmware_work,
+				      msecs_to_jiffies(1000));
 }
 
 /*
@@ -1114,22 +1110,6 @@ static int snd_emu10k1_emu1010_init(struct snd_emu10k1 *emu)
 	snd_emu1010_fpga_read(emu, EMU_HANA_SPDIF_MODE, &tmp);
 	snd_emu1010_fpga_write(emu, EMU_HANA_SPDIF_MODE, 0x10); /* SPDIF Format spdif  (or 0x11 for aes/ebu) */
 
-	/* Start Micro/Audio Dock firmware loader thread */
-	if (!emu->emu1010.firmware_thread) {
-		emu->emu1010.firmware_thread =
-			kthread_create(emu1010_firmware_thread, emu,
-				       "emu1010_firmware");
-		if (IS_ERR(emu->emu1010.firmware_thread)) {
-			err = PTR_ERR(emu->emu1010.firmware_thread);
-			emu->emu1010.firmware_thread = NULL;
-			dev_info(emu->card->dev,
-					"emu1010: Creating thread failed\n");
-			return err;
-		}
-
-		wake_up_process(emu->emu1010.firmware_thread);
-	}
-
 #if 0
 	snd_emu1010_fpga_link_dst_src_write(emu,
 		EMU_DST_HAMOA_DAC_LEFT1, EMU_SRC_ALICE_EMU32B + 2); /* ALICE2 bus 0xa2 */
@@ -1287,8 +1267,7 @@ static int snd_emu10k1_free(struct snd_emu10k1 *emu)
 		/* Disable 48Volt power to Audio Dock */
 		snd_emu1010_fpga_write(emu, EMU_HANA_DOCK_PWR, 0);
 	}
-	if (emu->emu1010.firmware_thread)
-		kthread_stop(emu->emu1010.firmware_thread);
+	cancel_delayed_work_sync(&emu->emu1010.firmware_work);
 	release_firmware(emu->firmware);
 	release_firmware(emu->dock_fw);
 	if (emu->irq >= 0)
@@ -1830,6 +1809,7 @@ int snd_emu10k1_create(struct snd_card *card,
 	emu->irq = -1;
 	emu->synth = NULL;
 	emu->get_synth_voice = NULL;
+	INIT_DELAYED_WORK(&emu->emu1010.firmware_work, emu1010_firmware_work);
 	/* read revision & serial */
 	emu->revision = pci->revision;
 	pci_read_config_dword(pci, PCI_SUBSYSTEM_VENDOR_ID, &emu->serial);