fpga zynq: Check for errors after completing DMA

The completion did not check the interrupt status to see if any error
bits were asserted, check error bits and dump some registers if things
went wrong.

A few fixes are needed to make this work, the IXR_ERROR_FLAGS_MASK was
wrong, it included the done bits, which shows a bug in mask/unmask_irqs
which were using the wrong bits, simplify all of this stuff.

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Moritz Fischer <moritz.fischer@ettus.com>
Acked-by: Alan Tull <atull@opensource.altera.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fpga/zynq-fpga.c

@@ -89,7 +89,7 @@
 #define IXR_D_P_DONE_MASK		BIT(12)
  /* FPGA programmed */
 #define IXR_PCFG_DONE_MASK		BIT(2)
-#define IXR_ERROR_FLAGS_MASK		0x00F0F860
+#define IXR_ERROR_FLAGS_MASK		0x00F0C860
 #define IXR_ALL_MASK			0xF8F7F87F
 
 /* Miscellaneous constant values */
@@ -143,31 +143,18 @@ static inline u32 zynq_fpga_read(const struct zynq_fpga_priv *priv,
 	readl_poll_timeout(priv->io_base + addr, val, cond, sleep_us, \
 			   timeout_us)
 
-static void zynq_fpga_mask_irqs(struct zynq_fpga_priv *priv)
+/* Cause the specified irq mask bits to generate IRQs */
+static inline void zynq_fpga_set_irq(struct zynq_fpga_priv *priv, u32 enable)
 {
-	u32 intr_mask;
-
-	intr_mask = zynq_fpga_read(priv, INT_MASK_OFFSET);
-	zynq_fpga_write(priv, INT_MASK_OFFSET,
-			intr_mask | IXR_DMA_DONE_MASK | IXR_ERROR_FLAGS_MASK);
-}
-
-static void zynq_fpga_unmask_irqs(struct zynq_fpga_priv *priv)
-{
-	u32 intr_mask;
-
-	intr_mask = zynq_fpga_read(priv, INT_MASK_OFFSET);
-	zynq_fpga_write(priv, INT_MASK_OFFSET,
-			intr_mask
-			& ~(IXR_D_P_DONE_MASK | IXR_ERROR_FLAGS_MASK));
+	zynq_fpga_write(priv, INT_MASK_OFFSET, ~enable);
 }
 
 static irqreturn_t zynq_fpga_isr(int irq, void *data)
 {
 	struct zynq_fpga_priv *priv = data;
 
 	/* disable DMA and error IRQs */
-	zynq_fpga_mask_irqs(priv);
+	zynq_fpga_set_irq(priv, 0);
 
 	complete(&priv->dma_done);
 
@@ -285,6 +272,7 @@ static int zynq_fpga_ops_write(struct fpga_manager *mgr,
 			       const char *buf, size_t count)
 {
 	struct zynq_fpga_priv *priv;
+	const char *why;
 	int err;
 	char *kbuf;
 	size_t in_count;
@@ -312,7 +300,7 @@ static int zynq_fpga_ops_write(struct fpga_manager *mgr,
 	reinit_completion(&priv->dma_done);
 
 	/* enable DMA and error IRQs */
-	zynq_fpga_unmask_irqs(priv);
+	zynq_fpga_set_irq(priv, IXR_D_P_DONE_MASK | IXR_ERROR_FLAGS_MASK);
 
 	/* the +1 in the src addr is used to hold off on DMA_DONE IRQ
 	 * until both AXI and PCAP are done ...
@@ -331,11 +319,33 @@ static int zynq_fpga_ops_write(struct fpga_manager *mgr,
 	intr_status = zynq_fpga_read(priv, INT_STS_OFFSET);
 	zynq_fpga_write(priv, INT_STS_OFFSET, intr_status);
 
+	if (intr_status & IXR_ERROR_FLAGS_MASK) {
+		why = "DMA reported error";
+		err = -EIO;
+		goto out_report;
+	}
+
 	if (!((intr_status & IXR_D_P_DONE_MASK) == IXR_D_P_DONE_MASK)) {
-		dev_err(&mgr->dev, "Error configuring FPGA\n");
-		err = -EFAULT;
+		why = "DMA did not complete";
+		err = -EIO;
+		goto out_report;
 	}
 
+	err = 0;
+	goto out_clk;
+
+out_report:
+	dev_err(&mgr->dev,
+		"%s: INT_STS:0x%x CTRL:0x%x LOCK:0x%x INT_MASK:0x%x STATUS:0x%x MCTRL:0x%x\n",
+		why,
+		intr_status,
+		zynq_fpga_read(priv, CTRL_OFFSET),
+		zynq_fpga_read(priv, LOCK_OFFSET),
+		zynq_fpga_read(priv, INT_MASK_OFFSET),
+		zynq_fpga_read(priv, STATUS_OFFSET),
+		zynq_fpga_read(priv, MCTRL_OFFSET));
+
+out_clk:
 	clk_disable(priv->clk);
 
 out_free:
@@ -452,7 +462,7 @@ static int zynq_fpga_probe(struct platform_device *pdev)
 	/* unlock the device */
 	zynq_fpga_write(priv, UNLOCK_OFFSET, UNLOCK_MASK);
 
-	zynq_fpga_write(priv, INT_MASK_OFFSET, 0xFFFFFFFF);
+	zynq_fpga_set_irq(priv, 0);
 	zynq_fpga_write(priv, INT_STS_OFFSET, IXR_ALL_MASK);
 	err = devm_request_irq(dev, priv->irq, zynq_fpga_isr, 0, dev_name(dev),
 			       priv);