usb: renesas: fix scheduling in atomic context bug

The current renesas_usbhs driver triggers

BUG: scheduling while atomic: ksoftirqd/0/3/0x00000102

with enabled CONFIG_DEBUG_ATOMIC_SLEEP, by submitting DMA transfers from
an atomic (tasklet) context, which is not supported by the shdma dmaengine
driver. Fix it by switching to a work.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

2 files changed, 8 insertions, 13 deletions

diff --git a/drivers/usb/renesas_usbhs/fifo.c b/drivers/usb/renesas_usbhs/fifo.c
index fb2a88c5c210..3648c82a17fe 100644
--- a/drivers/usb/renesas_usbhs/fifo.c
+++ b/drivers/usb/renesas_usbhs/fifo.c
@@ -765,9 +765,9 @@ static int __usbhsf_dma_map_ctrl(struct usbhs_pkt *pkt, int map)
 }
 
 static void usbhsf_dma_complete(void *arg);
-static void usbhsf_dma_prepare_tasklet(unsigned long data)
+static void xfer_work(struct work_struct *work)
 {
-        struct usbhs_pkt *pkt = (struct usbhs_pkt *)data;
+        struct usbhs_pkt *pkt = container_of(work, struct usbhs_pkt, work);
         struct usbhs_pipe *pipe = pkt->pipe;
         struct usbhs_fifo *fifo = usbhs_pipe_to_fifo(pipe);
         struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
@@ -847,11 +847,8 @@ static int usbhsf_dma_prepare_push(struct usbhs_pkt *pkt, int *is_done)
 
         pkt->trans = len;
 
-        tasklet_init(&fifo->tasklet,
-                     usbhsf_dma_prepare_tasklet,
-                     (unsigned long)pkt);
-
-        tasklet_schedule(&fifo->tasklet);
+        INIT_WORK(&pkt->work, xfer_work);
+        schedule_work(&pkt->work);
 
         return 0;
 
@@ -941,11 +938,8 @@ static int usbhsf_dma_try_pop(struct usbhs_pkt *pkt, int *is_done)
 
         pkt->trans = len;
 
-        tasklet_init(&fifo->tasklet,
-                     usbhsf_dma_prepare_tasklet,
-                     (unsigned long)pkt);
-
-        tasklet_schedule(&fifo->tasklet);
+        INIT_WORK(&pkt->work, xfer_work);
+        schedule_work(&pkt->work);
 
         return 0;
 
diff --git a/drivers/usb/renesas_usbhs/fifo.h b/drivers/usb/renesas_usbhs/fifo.h
index f68609c0f489..c31731a843d1 100644
--- a/drivers/usb/renesas_usbhs/fifo.h
+++ b/drivers/usb/renesas_usbhs/fifo.h
@@ -19,6 +19,7 @@
 
 #include <linux/interrupt.h>
 #include <linux/sh_dma.h>
+#include <linux/workqueue.h>
 #include <asm/dma.h>
 #include "pipe.h"
 
@@ -31,7 +32,6 @@ struct usbhs_fifo {
         u32 ctr;        /* xFIFOCTR */
 
         struct usbhs_pipe       *pipe;
-        struct tasklet_struct   tasklet;
 
         struct dma_chan         *tx_chan;
         struct dma_chan         *rx_chan;
@@ -53,6 +53,7 @@ struct usbhs_pkt {
         struct usbhs_pkt_handle *handler;
         void (*done)(struct usbhs_priv *priv,
                      struct usbhs_pkt *pkt);
+        struct work_struct work;
         dma_addr_t dma;
         void *buf;
         int length;