dm: implement a DMA uclass

Implement a DMA uclass so that the devices like ethernet, spi,
mmc etc can offload the data transfers from/to the device and
memory.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagan Teki <jteki@openedev.com>

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..58cb6e953131b2eb1d35f68f094ea8e0fb65802d 100644 (file)
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -0,0 +1,15 @@
+menu "DMA Support"
+
+config DMA
+       bool "Enable Driver Model for DMA drivers"
+       depends on DM
+       help
+         Enable driver model for DMA. DMA engines can do
+         asynchronous data transfers without involving the host
+         CPU. Currently, this framework can be used to offload
+         memory copies to and from devices like qspi, ethernet
+         etc Drivers provide methods to access the DMA devices
+         buses that is used to transfer data to and from memory.
+         The uclass interface is defined in include/dma.h.
+
+endmenu # menu "DMA Support"

diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index f95fe70a99976f969dd0251f589a8ae7340575a1..39b78b2a3d62634b63d1e8963fe9306ff1582339 100644 (file)
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -5,6 +5,8 @@
 # SPDX-License-Identifier:     GPL-2.0+
 #
 
+obj-$(CONFIG_DMA) += dma-uclass.o
+
 obj-$(CONFIG_FSLDMAFEC) += MCD_tasksInit.o MCD_dmaApi.o MCD_tasks.o
 obj-$(CONFIG_APBH_DMA) += apbh_dma.o
 obj-$(CONFIG_FSL_DMA) += fsl_dma.o

diff --git a/drivers/dma/dma-uclass.c b/drivers/dma/dma-uclass.c
new file mode 100644 (file)
index 0000000..ea21fd9
--- /dev/null
+++ b/drivers/dma/dma-uclass.c
@@ -0,0 +1,72 @@
+/*
+ * Direct Memory Access U-Class driver
+ *
+ * (C) Copyright 2015
+ *     Texas Instruments Incorporated, <www.ti.com>
+ *
+ * Author: Mugunthan V N <mugunthanvnm@ti.com>
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <common.h>
+#include <dma.h>
+#include <dm.h>
+#include <dm/uclass-internal.h>
+#include <dm/device-internal.h>
+#include <errno.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int dma_get_device(u32 transfer_type, struct udevice **devp)
+{
+       struct udevice *dev;
+       int ret;
+
+       for (ret = uclass_first_device(UCLASS_DMA, &dev); dev && !ret;
+            ret = uclass_next_device(&dev)) {
+               struct dma_dev_priv *uc_priv;
+
+               uc_priv = dev_get_uclass_priv(dev);
+               if (uc_priv->supported & transfer_type)
+                       break;
+       }
+
+       if (!dev) {
+               error("No DMA device found that supports %x type\n",
+                     transfer_type);
+               return -EPROTONOSUPPORT;
+       }
+
+       *devp = dev;
+
+       return ret;
+}
+
+int dma_memcpy(void *dst, void *src, size_t len)
+{
+       struct udevice *dev;
+       const struct dma_ops *ops;
+       int ret;
+
+       ret = dma_get_device(DMA_SUPPORTS_MEM_TO_MEM, &dev);
+       if (ret < 0)
+               return ret;
+
+       ops = device_get_ops(dev);
+       if (!ops->transfer)
+               return -ENOSYS;
+
+       /* Invalidate the area, so no writeback into the RAM races with DMA */
+       invalidate_dcache_range((unsigned long)dst, (unsigned long)dst +
+                               roundup(len, ARCH_DMA_MINALIGN));
+
+       return ops->transfer(dev, DMA_MEM_TO_MEM, dst, src, len);
+}
+
+UCLASS_DRIVER(dma) = {
+       .id             = UCLASS_DMA,
+       .name           = "dma",
+       .flags          = DM_UC_FLAG_SEQ_ALIAS,
+       .per_device_auto_alloc_size = sizeof(struct dma_dev_priv),
+};

diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 73cd3ac94c17b9eedcced305c7277d4eed6cac77..3bea30807dbb0cda6c49425735645537ff7dffa0 100644 (file)
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -31,6 +31,7 @@ enum uclass_id {
        UCLASS_CROS_EC,         /* Chrome OS EC */
        UCLASS_DISK,            /* Disk controller, e.g. SATA */
        UCLASS_DISPLAY,         /* Display (e.g. DisplayPort, HDMI) */
+       UCLASS_DMA,             /* Direct Memory Access */
        UCLASS_RAM,             /* RAM controller */
        UCLASS_ETH,             /* Ethernet device */
        UCLASS_GPIO,            /* Bank of general-purpose I/O pins */

diff --git a/include/dma.h b/include/dma.h
new file mode 100644 (file)
index 0000000..71fa77f
--- /dev/null
+++ b/include/dma.h
@@ -0,0 +1,86 @@
+/*
+ * (C) Copyright 2015
+ *     Texas Instruments Incorporated, <www.ti.com>
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#ifndef _DMA_H_
+#define _DMA_H_
+
+/*
+ * enum dma_direction - dma transfer direction indicator
+ * @DMA_MEM_TO_MEM: Memcpy mode
+ * @DMA_MEM_TO_DEV: From Memory to Device
+ * @DMA_DEV_TO_MEM: From Device to Memory
+ * @DMA_DEV_TO_DEV: From Device to Device
+ */
+enum dma_direction {
+       DMA_MEM_TO_MEM,
+       DMA_MEM_TO_DEV,
+       DMA_DEV_TO_MEM,
+       DMA_DEV_TO_DEV,
+};
+
+#define DMA_SUPPORTS_MEM_TO_MEM        BIT(0)
+#define DMA_SUPPORTS_MEM_TO_DEV        BIT(1)
+#define DMA_SUPPORTS_DEV_TO_MEM        BIT(2)
+#define DMA_SUPPORTS_DEV_TO_DEV        BIT(3)
+
+/*
+ * struct dma_ops - Driver model DMA operations
+ *
+ * The uclass interface is implemented by all DMA devices which use
+ * driver model.
+ */
+struct dma_ops {
+       /*
+        * Get the current timer count
+        *
+        * @dev: The DMA device
+        * @direction: direction of data transfer should be one from
+                      enum dma_direction
+        * @dst: Destination pointer
+        * @src: Source pointer
+        * @len: Length of the data to be copied.
+        * @return: 0 if OK, -ve on error
+        */
+       int (*transfer)(struct udevice *dev, int direction, void *dst,
+                       void *src, size_t len);
+};
+
+/*
+ * struct dma_dev_priv - information about a device used by the uclass
+ *
+ * @supported: mode of transfers that DMA can support, should be
+ *            one/multiple of DMA_SUPPORTS_*
+ */
+struct dma_dev_priv {
+       u32 supported;
+};
+
+/*
+ * dma_get_device - get a DMA device which supports transfer
+ * type of transfer_type
+ *
+ * @transfer_type - transfer type should be one/multiple of
+ *                 DMA_SUPPORTS_*
+ * @devp - udevice pointer to return the found device
+ * @return - will return on success and devp will hold the
+ *          pointer to the device
+ */
+int dma_get_device(u32 transfer_type, struct udevice **devp);
+
+/*
+ * dma_memcpy - try to use DMA to do a mem copy which will be
+ *             much faster than CPU mem copy
+ *
+ * @dst - destination pointer
+ * @src - souce pointer
+ * @len - data length to be copied
+ * @return - on successful transfer returns no of bytes
+            transferred and on failure return error code.
+ */
+int dma_memcpy(void *dst, void *src, size_t len);
+
+#endif /* _DMA_H_ */