mmc: Convert from tasklet to BH workqueue

The only generic interface to execute asynchronously in the BH context is
tasklet; however, it's marked deprecated and has some design flaws. To
replace tasklets, BH workqueue support was recently added. A BH workqueue
behaves similarly to regular workqueues except that the queued work items
are executed in the BH context.

This patch converts drivers/mmc/* from tasklet to BH workqueue.

Based on the work done by Tejun Heo <tj@kernel.org>

Tested-by: Christian Loehle <christian.loehle@arm.com>
Tested-by: Aubin Constans <aubin.constans@microchip.com>
Acked-by: Aubin Constans <aubin.constans@microchip.com>
Acked-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Christian Loehle <christian.loehle@arm.com>
Signed-off-by: Allen Pais <allen.lkml@gmail.com>
Link: https://lore.kernel.org/r/20240701100736.4001658-1-allen.lkml@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 19 insertions, 18 deletions

diff --git a/drivers/mmc/host/au1xmmc.c b/drivers/mmc/host/au1xmmc.c
index b5a5c6a2fe8b..6e80bcb668ec 100644
--- a/drivers/mmc/host/au1xmmc.c
+++ b/drivers/mmc/host/au1xmmc.c
@@ -42,6 +42,7 @@
 #include <linux/leds.h>
 #include <linux/mmc/host.h>
 #include <linux/slab.h>
+#include <linux/workqueue.h>
 
 #include <asm/io.h>
 #include <asm/mach-au1x00/au1000.h>
@@ -113,8 +114,8 @@ struct au1xmmc_host {
 
 	int irq;
 
-	struct tasklet_struct finish_task;
-	struct tasklet_struct data_task;
+	struct work_struct finish_bh_work;
+	struct work_struct data_bh_work;
 	struct au1xmmc_platform_data *platdata;
 	struct platform_device *pdev;
 	struct resource *ioarea;
@@ -253,9 +254,9 @@ static void au1xmmc_finish_request(struct au1xmmc_host *host)
 	mmc_request_done(host->mmc, mrq);
 }
 
-static void au1xmmc_tasklet_finish(struct tasklet_struct *t)
+static void au1xmmc_finish_bh_work(struct work_struct *t)
 {
-	struct au1xmmc_host *host = from_tasklet(host, t, finish_task);
+	struct au1xmmc_host *host = from_work(host, t, finish_bh_work);
 	au1xmmc_finish_request(host);
 }
 
@@ -363,9 +364,9 @@ static void au1xmmc_data_complete(struct au1xmmc_host *host, u32 status)
 	au1xmmc_finish_request(host);
 }
 
-static void au1xmmc_tasklet_data(struct tasklet_struct *t)
+static void au1xmmc_data_bh_work(struct work_struct *t)
 {
-	struct au1xmmc_host *host = from_tasklet(host, t, data_task);
+	struct au1xmmc_host *host = from_work(host, t, data_bh_work);
 
 	u32 status = __raw_readl(HOST_STATUS(host));
 	au1xmmc_data_complete(host, status);
@@ -425,7 +426,7 @@ static void au1xmmc_send_pio(struct au1xmmc_host *host)
 		if (host->flags & HOST_F_STOP)
 			SEND_STOP(host);
 
-		tasklet_schedule(&host->data_task);
+		queue_work(system_bh_wq, &host->data_bh_work);
 	}
 }
 
@@ -505,7 +506,7 @@ static void au1xmmc_receive_pio(struct au1xmmc_host *host)
 		if (host->flags & HOST_F_STOP)
 			SEND_STOP(host);
 
-		tasklet_schedule(&host->data_task);
+		queue_work(system_bh_wq, &host->data_bh_work);
 	}
 }
 
@@ -561,7 +562,7 @@ static void au1xmmc_cmd_complete(struct au1xmmc_host *host, u32 status)
 
 	if (!trans || cmd->error) {
 		IRQ_OFF(host, SD_CONFIG_TH | SD_CONFIG_RA | SD_CONFIG_RF);
-		tasklet_schedule(&host->finish_task);
+		queue_work(system_bh_wq, &host->finish_bh_work);
 		return;
 	}
 
@@ -797,7 +798,7 @@ static irqreturn_t au1xmmc_irq(int irq, void *dev_id)
 		IRQ_OFF(host, SD_CONFIG_NE | SD_CONFIG_TH);
 
 		/* IRQ_OFF(host, SD_CONFIG_TH | SD_CONFIG_RA | SD_CONFIG_RF); */
-		tasklet_schedule(&host->finish_task);
+		queue_work(system_bh_wq, &host->finish_bh_work);
 	}
 #if 0
 	else if (status & SD_STATUS_DD) {
@@ -806,7 +807,7 @@ static irqreturn_t au1xmmc_irq(int irq, void *dev_id)
 			au1xmmc_receive_pio(host);
 		else {
 			au1xmmc_data_complete(host, status);
-			/* tasklet_schedule(&host->data_task); */
+			/* queue_work(system_bh_wq, &host->data_bh_work); */
 		}
 	}
 #endif
@@ -854,7 +855,7 @@ static void au1xmmc_dbdma_callback(int irq, void *dev_id)
 	if (host->flags & HOST_F_STOP)
 		SEND_STOP(host);
 
-	tasklet_schedule(&host->data_task);
+	queue_work(system_bh_wq, &host->data_bh_work);
 }
 
 static int au1xmmc_dbdma_init(struct au1xmmc_host *host)
@@ -1039,9 +1040,9 @@ static int au1xmmc_probe(struct platform_device *pdev)
 	if (host->platdata)
 		mmc->caps &= ~(host->platdata->mask_host_caps);
 
-	tasklet_setup(&host->data_task, au1xmmc_tasklet_data);
+	INIT_WORK(&host->data_bh_work, au1xmmc_data_bh_work);
 
-	tasklet_setup(&host->finish_task, au1xmmc_tasklet_finish);
+	INIT_WORK(&host->finish_bh_work, au1xmmc_finish_bh_work);
 
 	if (has_dbdma()) {
 		ret = au1xmmc_dbdma_init(host);
@@ -1091,8 +1092,8 @@ out5:
 	if (host->flags & HOST_F_DBDMA)
 		au1xmmc_dbdma_shutdown(host);
 
-	tasklet_kill(&host->data_task);
-	tasklet_kill(&host->finish_task);
+	cancel_work_sync(&host->data_bh_work);
+	cancel_work_sync(&host->finish_bh_work);
 
 	if (host->platdata && host->platdata->cd_setup &&
 	    !(mmc->caps & MMC_CAP_NEEDS_POLL))
@@ -1135,8 +1136,8 @@ static void au1xmmc_remove(struct platform_device *pdev)
 		__raw_writel(0, HOST_CONFIG2(host));
 		wmb(); /* drain writebuffer */
 
-		tasklet_kill(&host->data_task);
-		tasklet_kill(&host->finish_task);
+		cancel_work_sync(&host->data_bh_work);
+		cancel_work_sync(&host->finish_bh_work);
 
 		if (host->flags & HOST_F_DBDMA)
 			au1xmmc_dbdma_shutdown(host);