mtd: sh_flctl: pass FIFO as physical address

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=1873315fb156cbc8e46f28e8b128f17ff6c31728
Commit:     1873315fb156cbc8e46f28e8b128f17ff6c31728
Parent:     0ed6ca3a22f871fdb7335194f6488d14b2dad96a
Author:     Arnd Bergmann <arnd at arndb.de>
AuthorDate: Tue Dec 8 16:38:12 2015 +0100
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Fri Dec 18 18:27:13 2015 -0800

    mtd: sh_flctl: pass FIFO as physical address
    
    By convention, the FIFO address we pass using dmaengine_slave_config
    is a physical address in the form that is understood by the DMA
    engine, as a dma_addr_t, phys_addr_t or resource_size_t.
    
    The sh_flctl driver however passes a virtual __iomem address that
    gets cast to dma_addr_t in the slave driver. This happens to work
    on shmobile because that platform sets up an identity mapping for
    its MMIO regions, but such code is not portable to other platforms,
    and prevents us from ever changing the platform mapping or reusing
    the driver on other architectures like ARM64 that might not have the
    mapping.
    
    We also get a warning about a type mismatch for the case that
    dma_addr_t is wider than a pointer, i.e. when CONFIG_LPAE is set:
    
    drivers/mtd/nand/sh_flctl.c: In function 'flctl_setup_dma':
    drivers/mtd/nand/sh_flctl.c:163:17: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
      cfg.dst_addr = (dma_addr_t)FLDTFIFO(flctl);
    
    This changes the driver to instead pass the physical address of
    the FIFO that is extracted from the MMIO resource, making the
    code more portable and avoiding the warning.
    
    Signed-off-by: Arnd Bergmann <arnd at arndb.de>
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
---
 drivers/mtd/nand/sh_flctl.c  | 5 +++--
 include/linux/mtd/sh_flctl.h | 1 +
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/sh_flctl.c b/drivers/mtd/nand/sh_flctl.c
index c7126b7..4814402 100644
--- a/drivers/mtd/nand/sh_flctl.c
+++ b/drivers/mtd/nand/sh_flctl.c
@@ -160,7 +160,7 @@ static void flctl_setup_dma(struct sh_flctl *flctl)
 
 	memset(&cfg, 0, sizeof(cfg));
 	cfg.direction = DMA_MEM_TO_DEV;
-	cfg.dst_addr = (dma_addr_t)FLDTFIFO(flctl);
+	cfg.dst_addr = flctl->fifo;
 	cfg.src_addr = 0;
 	ret = dmaengine_slave_config(flctl->chan_fifo0_tx, &cfg);
 	if (ret < 0)
@@ -176,7 +176,7 @@ static void flctl_setup_dma(struct sh_flctl *flctl)
 
 	cfg.direction = DMA_DEV_TO_MEM;
 	cfg.dst_addr = 0;
-	cfg.src_addr = (dma_addr_t)FLDTFIFO(flctl);
+	cfg.src_addr = flctl->fifo;
 	ret = dmaengine_slave_config(flctl->chan_fifo0_rx, &cfg);
 	if (ret < 0)
 		goto err;
@@ -1095,6 +1095,7 @@ static int flctl_probe(struct platform_device *pdev)
 	flctl->reg = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(flctl->reg))
 		return PTR_ERR(flctl->reg);
+	flctl->fifo = res->start + 0x24; /* FLDTFIFO */
 
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
diff --git a/include/linux/mtd/sh_flctl.h b/include/linux/mtd/sh_flctl.h
index 76e3e88..2251add 100644
--- a/include/linux/mtd/sh_flctl.h
+++ b/include/linux/mtd/sh_flctl.h
@@ -147,6 +147,7 @@ struct sh_flctl {
 	struct platform_device	*pdev;
 	struct dev_pm_qos_request pm_qos;
 	void __iomem		*reg;
+	resource_size_t		fifo;
 
 	uint8_t	done_buff[2048 + 64];	/* max size 2048 + 64 */
 	int	read_bytes;