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@arndb.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

diff --git a/drivers/mtd/nand/sh_flctl.c b/drivers/mtd/nand/sh_flctl.c
index c7126b75fb0149d7c134b80f0a2f74890698df8e..4814402902f96df8ff10e370c34aefdde8dcf4f1 100644 (file)
--- 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 76e3e88bedfebb096a13db6885faa6105077091c..2251add65fa7e4fec83ebd6ec7b4347e5fc7863f 100644 (file)
--- 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;