wishbone: get serious about sleeping in interrupt context

pcie-wb/pcie_wb.c

@@ -216,6 +216,8 @@ static wb_data_t wb_read_cfg(struct wishbone *wb, wb_addr_t addr)
 
 static int wb_request(struct wishbone *wb, struct wishbone_request *req)
 {
+	/* All forms of sleep are forbidden in this method (no printk/mutex/etc) */
+	
 	struct pcie_wb_dev* dev;
 	unsigned char* control;
 	uint32_t ctl;
@@ -230,7 +232,6 @@ static int wb_request(struct wishbone *wb, struct wishbone_request *req)
 	req->mask  = ctl & 0xf;
 	req->write = (ctl & 0x40000000) != 0;
 	
-	if (unlikely(debug)) printk(KERN_ALERT "request %x\n", ctl);
 	out = (ctl & 0x80000000) != 0;
 	
 	if (out) iowrite32(1, control + MASTER_CTL_HIGH); /* dequeue operation */
@@ -242,13 +243,14 @@ static int wb_request(struct wishbone *wb, struct wishbone_request *req)
 
 static void wb_reply(struct wishbone *wb, int err, wb_data_t data)
 {
+	/* All forms of sleep are forbidden in this method (no printk/mutex/etc) */
+	
 	struct pcie_wb_dev* dev;
 	unsigned char* control;
 	
 	dev = container_of(wb, struct pcie_wb_dev, wb);
 	control = dev->pci_res[0].addr;
 	
-	if (unlikely(debug)) printk(KERN_ALERT "pushing reply\n");
 	iowrite32(data, control + MASTER_DAT_LOW);
 	iowrite32(err+2, control + MASTER_CTL_HIGH);
 }
@@ -266,9 +268,9 @@ static const struct wishbone_operations wb_ops = {
 
 static irqreturn_t irq_handler(int irq, void *dev_id)
 {
-	struct pcie_wb_dev *dev = dev_id;
+	/* All forms of sleep are forbidden in this method (no printk/mutex/etc) */
 	
-	if (unlikely(debug)) printk(KERN_ALERT "posting MSI\n");
+	struct pcie_wb_dev *dev = dev_id;
 	
 	pcie_int_enable(dev, 0);
 	wishbone_slave_ready(&dev->wb);

pcie-wb/wishbone.h

@@ -46,7 +46,7 @@ struct wishbone_operations
 	wb_data_t (*read)(struct wishbone *wb, wb_addr_t addr);
 	wb_data_t (*read_cfg)(struct wishbone *wb, wb_addr_t addr);
 	
-	/* slave operations */
+	/* slave operations, run from interrupt context => MUST NOT SLEEP (no printk/mutex/etc) */
 	int (*request)(struct wishbone *wb, struct wishbone_request*); /* 1=record filled, 0=none pending. re-enable non-MSI interrupts. */
 	void (*reply)(struct wishbone *wb, int err, wb_data_t dat);
 };

vme-wb/vme_wb_external.c

@@ -154,6 +154,8 @@ static wb_data_t wb_read(struct wishbone *wb, wb_addr_t addr)
 
 static int wb_request(struct wishbone *wb, struct wishbone_request *req)
 {
+	/* All forms of sleep are forbidden in this method (no printk/mutex/etc) */
+	
 	struct vme_wb_dev *dev;
 	unsigned char *ctrl_win;
 	uint32_t ctrl;
@@ -171,17 +173,13 @@ static int wb_request(struct wishbone *wb, struct wishbone_request *req)
 	out = (ctrl & 0x80000000) != 0;
 	if (out) iowrite32(cpu_to_be32(1), ctrl_win + MASTER_CTRL);	/* dequeue operation */
 
-	if (unlikely(debug))
-		printk(KERN_ALERT
-		       "WB REQUEST:Request ctrl %x addr %x data %x mask %x return %x \n",
-		       ctrl, req->addr, req->data, req->mask,
-		       (ctrl & 0x80000000) != 0);
-
 	return out;
 }
 
 static void wb_reply(struct wishbone *wb, int err, wb_data_t data)
 {
+	/* All forms of sleep are forbidden in this method (no printk/mutex/etc) */
+	
 	struct vme_wb_dev *dev;
 	unsigned char *ctrl_win;
 
@@ -190,10 +188,6 @@ static void wb_reply(struct wishbone *wb, int err, wb_data_t data)
 
 	iowrite32(cpu_to_be32(data), ctrl_win + MASTER_DATA);
 	iowrite32(cpu_to_be32(err + 2), ctrl_win + MASTER_CTRL);
-
-	if (unlikely(debug))
-		printk(KERN_ALERT "WB REPLY: pushing data %x reply %x\n", data,
-		       err + 2);
 }
 
 static void wb_byteenable(struct wishbone *wb, unsigned char be)
@@ -235,11 +229,10 @@ static void init_ctrl_reg(struct vme_wb_dev *dev)
 
 int irq_handler(void *dev_id)
 {
+	/* All forms of sleep are forbidden in this method (no printk/mutex/etc) */
+	
 	struct vme_wb_dev *dev = dev_id;
 
-        if (unlikely(debug))
-		printk(KERN_ALERT VME_WB ": IRQ!!\n");
-
 	wishbone_slave_ready(&dev->wb);
 
 	return IRQ_HANDLED;