linux-kernel - [PATCH] vme: fake: fix build for 64-bit dma_addr

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Date:   Tue,  6 Sep 2016 14:59:41 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Martyn Welch <martyn@...chs.me.uk>,
        Manohar Vanga <manohar.vanga@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Arnd Bergmann <arnd@...db.de>, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] vme: fake: fix build for 64-bit dma_addr_t

casting between dma_addr_t and a pointer is generally tricky,
as they might not be the same size and almost never point into
the same address space. With 32-bit ARM systems and LPAE, we
get this warning for the vme_fake driver that stores a pointer
in a dma_addr_t variable:

drivers/vme/bridges/vme_fake.c: In function 'fake_slave_set':
drivers/vme/bridges/vme_fake.c:204:29: error: assignment makes pointer from integer without a cast [-Werror=int-conversion]

To make this clearer while fixing the warning, I'm adding
a set of helper functions for the type conversion.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/vme/bridges/vme_fake.c | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/vme/bridges/vme_fake.c b/drivers/vme/bridges/vme_fake.c
index 7ef298b289f4..ebf35d305321 100644
--- a/drivers/vme/bridges/vme_fake.c
+++ b/drivers/vme/bridges/vme_fake.c
@@ -48,7 +48,7 @@ struct fake_slave_window {
 	int enabled;
 	unsigned long long vme_base;
 	unsigned long long size;
-	dma_addr_t buf_base;
+	void *buf_base;
 	u32 aspace;
 	u32 cycle;
 };
@@ -114,6 +114,16 @@ static void fake_irq_set(struct vme_bridge *fake_bridge, int level,
 	/* Nothing to do */
 }
 
+static void *fake_pci_to_ptr(dma_addr_t addr)
+{
+	return (void *)(uintptr_t)addr;
+}
+
+static dma_addr_t fake_ptr_to_pci(void *addr)
+{
+	return (dma_addr_t)(uintptr_t)addr;
+}
+
 /*
  * Generate a VME bus interrupt at the requested level & vector. Wait for
  * interrupt to be acked.
@@ -202,7 +212,7 @@ static int fake_slave_set(struct vme_slave_resource *image, int enabled,
 	bridge->slaves[i].enabled = enabled;
 	bridge->slaves[i].vme_base = vme_base;
 	bridge->slaves[i].size = size;
-	bridge->slaves[i].buf_base = buf_base;
+	bridge->slaves[i].buf_base = fake_pci_to_ptr(buf_base);
 	bridge->slaves[i].aspace = aspace;
 	bridge->slaves[i].cycle = cycle;
 
@@ -230,7 +240,7 @@ static int fake_slave_get(struct vme_slave_resource *image, int *enabled,
 	*enabled = bridge->slaves[i].enabled;
 	*vme_base = bridge->slaves[i].vme_base;
 	*size = bridge->slaves[i].size;
-	*buf_base = bridge->slaves[i].buf_base;
+	*buf_base = fake_ptr_to_pci(bridge->slaves[i].buf_base);
 	*aspace = bridge->slaves[i].aspace;
 	*cycle = bridge->slaves[i].cycle;
 
@@ -431,7 +441,7 @@ static u8 fake_vmeread8(struct fake_driver *bridge, unsigned long long addr,
 
 		if ((addr >= start) && (addr < end)) {
 			offset = addr - bridge->slaves[i].vme_base;
-			loc = (u8 *)((void *)bridge->slaves[i].buf_base + offset);
+			loc = (u8 *)(bridge->slaves[i].buf_base + offset);
 			retval = *loc;
 
 			break;
@@ -463,7 +473,7 @@ static u16 fake_vmeread16(struct fake_driver *bridge, unsigned long long addr,
 
 		if ((addr >= start) && ((addr + 1) < end)) {
 			offset = addr - bridge->slaves[i].vme_base;
-			loc = (u16 *)((void *)bridge->slaves[i].buf_base + offset);
+			loc = (u16 *)(bridge->slaves[i].buf_base + offset);
 			retval = *loc;
 
 			break;
@@ -495,7 +505,7 @@ static u32 fake_vmeread32(struct fake_driver *bridge, unsigned long long addr,
 
 		if ((addr >= start) && ((addr + 3) < end)) {
 			offset = addr - bridge->slaves[i].vme_base;
-			loc = (u32 *)((void *)bridge->slaves[i].buf_base + offset);
+			loc = (u32 *)(bridge->slaves[i].buf_base + offset);
 			retval = *loc;
 
 			break;
@@ -997,7 +1007,7 @@ static void *fake_alloc_consistent(struct device *parent, size_t size,
 	void *alloc = kmalloc(size, GFP_KERNEL);
 
 	if (alloc != NULL)
-		*dma = (dma_addr_t)(unsigned long)alloc;
+		*dma = fake_ptr_to_pci(alloc);
 
 	return alloc;
 }
@@ -1031,7 +1041,7 @@ static int fake_crcsr_init(struct vme_bridge *fake_bridge)
 
 	/* Allocate mem for CR/CSR image */
 	bridge->crcsr_kernel = kzalloc(VME_CRCSR_BUF_SIZE, GFP_KERNEL);
-	bridge->crcsr_bus = (dma_addr_t)bridge->crcsr_kernel;
+	bridge->crcsr_bus = fake_ptr_to_pci(bridge->crcsr_kernel);
 	if (bridge->crcsr_kernel == NULL)
 		return -ENOMEM;
 
-- 
2.9.0