[PATCH 3.16 086/192] parisc: DMA API: return error instead of BUG_ON for dma ops on non dma devs

[Ben Hutchings <ben@decadent.org.uk>]

3.16.49-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

commit 33f9e02495d15a061f0c94ef46f5103a2d0c20f3 upstream.

Enabling parport pc driver on a B2600 (and probably other 64bit PARISC
systems) produced following BUG:

CPU: 0 PID: 1 Comm: swapper Not tainted 4.12.0-rc5-30198-g1132d5e #156
task: 000000009e050000 task.stack: 000000009e04c000

     YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
PSW: 00001000000001101111111100001111 Not tainted
r00-03  000000ff0806ff0f 000000009e04c990 0000000040871b78 000000009e04cac0
r04-07  0000000040c14de0 ffffffffffffffff 000000009e07f098 000000009d82d200
r08-11  000000009d82d210 0000000000000378 0000000000000000 0000000040c345e0
r12-15  0000000000000005 0000000040c345e0 0000000000000000 0000000040c9d5e0
r16-19  0000000040c345e0 00000000f00001c4 00000000f00001bc 0000000000000061
r20-23  000000009e04ce28 0000000000000010 0000000000000010 0000000040b89e40
r24-27  0000000000000003 0000000000ffffff 000000009d82d210 0000000040c14de0
r28-31  0000000000000000 000000009e04ca90 000000009e04cb40 0000000000000000
sr00-03  0000000000000000 0000000000000000 0000000000000000 0000000000000000
sr04-07  0000000000000000 0000000000000000 0000000000000000 0000000000000000

IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000404aece0 00000000404aece4
 IIR: 03ffe01f    ISR: 0000000010340000  IOR: 000001781304cac8
 CPU:        0   CR30: 000000009e04c000 CR31: 00000000e2976de2
 ORIG_R28: 0000000000000200
 IAOQ[0]: sba_dma_supported+0x80/0xd0
 IAOQ[1]: sba_dma_supported+0x84/0xd0
 RP(r2): parport_pc_probe_port+0x178/0x1200

Cause is a call to dma_coerce_mask_and_coherenet in parport_pc_probe_port,
which PARISC DMA API doesn't handle very nicely. This commit gives back
DMA_ERROR_CODE for DMA API calls, if device isn't capable of DMA
transaction.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 arch/parisc/include/asm/dma-mapping.h | 11 +++++++----
 drivers/parisc/ccio-dma.c             | 12 ++++++++++++
 drivers/parisc/dino.c                 |  5 ++++-
 drivers/parisc/lba_pci.c              |  6 ++++--
 drivers/parisc/sba_iommu.c            | 14 ++++++++++++++
 5 files changed, 41 insertions(+), 7 deletions(-)

--- a/arch/parisc/include/asm/dma-mapping.h
+++ b/arch/parisc/include/asm/dma-mapping.h
@@ -39,6 +39,8 @@ struct hppa_dma_ops {
 ** flush/purge and allocate "regular" cacheable pages for everything.
 */
 
+#define DMA_ERROR_CODE	(~(dma_addr_t)0)
+
 #ifdef CONFIG_PA11
 extern struct hppa_dma_ops pcxl_dma_ops;
 extern struct hppa_dma_ops pcx_dma_ops;
@@ -209,12 +211,13 @@ parisc_walk_tree(struct device *dev)
 			break;
 		}
 	}
-	BUG_ON(!dev->platform_data);
 	return dev->platform_data;
 }
-		
-#define GET_IOC(dev) (HBA_DATA(parisc_walk_tree(dev))->iommu)
-	
+
+#define GET_IOC(dev) ({					\
+	void *__pdata = parisc_walk_tree(dev);		\
+	__pdata ? HBA_DATA(__pdata)->iommu : NULL;	\
+})
 
 #ifdef CONFIG_IOMMU_CCIO
 struct parisc_device;
--- a/drivers/parisc/ccio-dma.c
+++ b/drivers/parisc/ccio-dma.c
@@ -743,6 +743,8 @@ ccio_map_single(struct device *dev, void
 
 	BUG_ON(!dev);
 	ioc = GET_IOC(dev);
+	if (!ioc)
+		return DMA_ERROR_CODE;
 
 	BUG_ON(size <= 0);
 
@@ -807,6 +809,10 @@ ccio_unmap_single(struct device *dev, dm
 	
 	BUG_ON(!dev);
 	ioc = GET_IOC(dev);
+	if (!ioc) {
+		WARN_ON(!ioc);
+		return;
+	}
 
 	DBG_RUN("%s() iovp 0x%lx/%x\n",
 		__func__, (long)iova, size);
@@ -910,6 +916,8 @@ ccio_map_sg(struct device *dev, struct s
 	
 	BUG_ON(!dev);
 	ioc = GET_IOC(dev);
+	if (!ioc)
+		return 0;
 	
 	DBG_RUN_SG("%s() START %d entries\n", __func__, nents);
 
@@ -982,6 +990,10 @@ ccio_unmap_sg(struct device *dev, struct
 
 	BUG_ON(!dev);
 	ioc = GET_IOC(dev);
+	if (!ioc) {
+		WARN_ON(!ioc);
+		return;
+	}
 
 	DBG_RUN_SG("%s() START %d entries,  %08lx,%x\n",
 		__func__, nents, sg_virt_addr(sglist), sglist->length);
--- a/drivers/parisc/dino.c
+++ b/drivers/parisc/dino.c
@@ -154,7 +154,10 @@ struct dino_device
 };
 
 /* Looks nice and keeps the compiler happy */
-#define DINO_DEV(d) ((struct dino_device *) d)
+#define DINO_DEV(d) ({				\
+	void *__pdata = d;			\
+	BUG_ON(!__pdata);			\
+	(struct dino_device *)__pdata; })
 
 
 /*
--- a/drivers/parisc/lba_pci.c
+++ b/drivers/parisc/lba_pci.c
@@ -111,8 +111,10 @@ static u32 lba_t32;
 
 
 /* Looks nice and keeps the compiler happy */
-#define LBA_DEV(d) ((struct lba_device *) (d))
-
+#define LBA_DEV(d) ({				\
+	void *__pdata = d;			\
+	BUG_ON(!__pdata);			\
+	(struct lba_device *)__pdata; })
 
 /*
 ** Only allow 8 subsidiary busses per LBA
--- a/drivers/parisc/sba_iommu.c
+++ b/drivers/parisc/sba_iommu.c
@@ -691,6 +691,8 @@ static int sba_dma_supported( struct dev
 		return 0;
 
 	ioc = GET_IOC(dev);
+	if (!ioc)
+		return 0;
 
 	/*
 	 * check if mask is >= than the current max IO Virt Address
@@ -722,6 +724,8 @@ sba_map_single(struct device *dev, void
 	int pide;
 
 	ioc = GET_IOC(dev);
+	if (!ioc)
+		return DMA_ERROR_CODE;
 
 	/* save offset bits */
 	offset = ((dma_addr_t) (long) addr) & ~IOVP_MASK;
@@ -803,6 +807,10 @@ sba_unmap_single(struct device *dev, dma
 	DBG_RUN("%s() iovp 0x%lx/%x\n", __func__, (long) iova, size);
 
 	ioc = GET_IOC(dev);
+	if (!ioc) {
+		WARN_ON(!ioc);
+		return;
+	}
 	offset = iova & ~IOVP_MASK;
 	iova ^= offset;        /* clear offset bits */
 	size += offset;
@@ -942,6 +950,8 @@ sba_map_sg(struct device *dev, struct sc
 	DBG_RUN_SG("%s() START %d entries\n", __func__, nents);
 
 	ioc = GET_IOC(dev);
+	if (!ioc)
+		return 0;
 
 	/* Fast path single entry scatterlists. */
 	if (nents == 1) {
@@ -1028,6 +1038,10 @@ sba_unmap_sg(struct device *dev, struct
 		__func__, nents, sg_virt_addr(sglist), sglist->length);
 
 	ioc = GET_IOC(dev);
+	if (!ioc) {
+		WARN_ON(!ioc);
+		return;
+	}
 
 #ifdef SBA_COLLECT_STATS
 	ioc->usg_calls++;