This adds channels support for dma controllers that have multiple channels which can transfer data to/from different devices (enet, usb...).
DMA channle API: dma_get_by_index() dma_get_by_name() dma_request() dma_free() dma_enable() dma_disable() dma_prepare_rcv_buf() dma_receive() dma_send()
Reviewed-by: Tom Rini trini@konsulko.com Signed-off-by: Álvaro Fernández Rojas noltari@gmail.com [grygorii.strashko@ti.com: drop unused dma_get_by_index_platdata(), add metadata to send/receive ops, add dma_prepare_rcv_buf(), minor clean up] Signed-off-by: Grygorii Strashko grygorii.strashko@ti.com Reviewed-by: Simon Glass sjg@chromium.org --- v9: no changes v8: no changes v7: From Grygorii Strashko: - copyright fixed as suggested by Tom Rini - added "Reviewed-by" tags v6: From Grygorii Strashko: - added possibility to pass DMA driver/channel's specific data per each transfer using additional parameter "metadata" in dma_send/dma_receive() API. For example, port number for network packets to be directed to the specific port on multi port ethernet controllers. - added new dma_prepare_rcv_buf() API which allows to implement zero-copy DEV_TO_MEM transfer using DMA streaming channels which is usual case for Networking. - removed unused function dma_get_by_index_platdata() - updated comments v5: remove unneeded dma.h include v4: no changes v3: Introduce changes reported by Simon Glass: - Improve dma-uclass.h documentation. - Switch to live tree API.
drivers/dma/Kconfig | 7 ++ drivers/dma/dma-uclass.c | 181 ++++++++++++++++++++++++++++++++- include/dma-uclass.h | 91 ++++++++++++++++- include/dma.h | 260 ++++++++++++++++++++++++++++++++++++++++++++++- 4 files changed, 532 insertions(+), 7 deletions(-)
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig index 4ee6afad35..b9b85c65fc 100644 --- a/drivers/dma/Kconfig +++ b/drivers/dma/Kconfig @@ -12,6 +12,13 @@ config DMA buses that is used to transfer data to and from memory. The uclass interface is defined in include/dma.h.
+config DMA_CHANNELS + bool "Enable DMA channels support" + depends on DMA + help + Enable channels support for DMA. Some DMA controllers have multiple + channels which can either transfer data to/from different devices. + config TI_EDMA3 bool "TI EDMA3 driver" help diff --git a/drivers/dma/dma-uclass.c b/drivers/dma/dma-uclass.c index 6c3506c302..9c961cf1e2 100644 --- a/drivers/dma/dma-uclass.c +++ b/drivers/dma/dma-uclass.c @@ -2,19 +2,192 @@ /* * Direct Memory Access U-Class driver * - * (C) Copyright 2015 - * Texas Instruments Incorporated, <www.ti.com> + * Copyright (C) 2018 Álvaro Fernández Rojas noltari@gmail.com + * Copyright (C) 2015 - 2018 Texas Instruments Incorporated <www.ti.com> + * Written by Mugunthan V N mugunthanvnm@ti.com * * Author: Mugunthan V N mugunthanvnm@ti.com */
#include <common.h> #include <dm.h> -#include <dm/uclass-internal.h> -#include <dm/device-internal.h> +#include <dm/read.h> #include <dma-uclass.h> +#include <dt-structs.h> #include <errno.h>
+#ifdef CONFIG_DMA_CHANNELS +static inline struct dma_ops *dma_dev_ops(struct udevice *dev) +{ + return (struct dma_ops *)dev->driver->ops; +} + +# if CONFIG_IS_ENABLED(OF_CONTROL) +static int dma_of_xlate_default(struct dma *dma, + struct ofnode_phandle_args *args) +{ + debug("%s(dma=%p)\n", __func__, dma); + + if (args->args_count > 1) { + pr_err("Invaild args_count: %d\n", args->args_count); + return -EINVAL; + } + + if (args->args_count) + dma->id = args->args[0]; + else + dma->id = 0; + + return 0; +} + +int dma_get_by_index(struct udevice *dev, int index, struct dma *dma) +{ + int ret; + struct ofnode_phandle_args args; + struct udevice *dev_dma; + const struct dma_ops *ops; + + debug("%s(dev=%p, index=%d, dma=%p)\n", __func__, dev, index, dma); + + assert(dma); + dma->dev = NULL; + + ret = dev_read_phandle_with_args(dev, "dmas", "#dma-cells", 0, index, + &args); + if (ret) { + pr_err("%s: dev_read_phandle_with_args failed: err=%d\n", + __func__, ret); + return ret; + } + + ret = uclass_get_device_by_ofnode(UCLASS_DMA, args.node, &dev_dma); + if (ret) { + pr_err("%s: uclass_get_device_by_ofnode failed: err=%d\n", + __func__, ret); + return ret; + } + + dma->dev = dev_dma; + + ops = dma_dev_ops(dev_dma); + + if (ops->of_xlate) + ret = ops->of_xlate(dma, &args); + else + ret = dma_of_xlate_default(dma, &args); + if (ret) { + pr_err("of_xlate() failed: %d\n", ret); + return ret; + } + + return dma_request(dev_dma, dma); +} + +int dma_get_by_name(struct udevice *dev, const char *name, struct dma *dma) +{ + int index; + + debug("%s(dev=%p, name=%s, dma=%p)\n", __func__, dev, name, dma); + dma->dev = NULL; + + index = dev_read_stringlist_search(dev, "dma-names", name); + if (index < 0) { + pr_err("dev_read_stringlist_search() failed: %d\n", index); + return index; + } + + return dma_get_by_index(dev, index, dma); +} +# endif /* OF_CONTROL */ + +int dma_request(struct udevice *dev, struct dma *dma) +{ + struct dma_ops *ops = dma_dev_ops(dev); + + debug("%s(dev=%p, dma=%p)\n", __func__, dev, dma); + + dma->dev = dev; + + if (!ops->request) + return 0; + + return ops->request(dma); +} + +int dma_free(struct dma *dma) +{ + struct dma_ops *ops = dma_dev_ops(dma->dev); + + debug("%s(dma=%p)\n", __func__, dma); + + if (!ops->free) + return 0; + + return ops->free(dma); +} + +int dma_enable(struct dma *dma) +{ + struct dma_ops *ops = dma_dev_ops(dma->dev); + + debug("%s(dma=%p)\n", __func__, dma); + + if (!ops->enable) + return -ENOSYS; + + return ops->enable(dma); +} + +int dma_disable(struct dma *dma) +{ + struct dma_ops *ops = dma_dev_ops(dma->dev); + + debug("%s(dma=%p)\n", __func__, dma); + + if (!ops->disable) + return -ENOSYS; + + return ops->disable(dma); +} + +int dma_prepare_rcv_buf(struct dma *dma, void *dst, size_t size) +{ + struct dma_ops *ops = dma_dev_ops(dma->dev); + + debug("%s(dma=%p)\n", __func__, dma); + + if (!ops->prepare_rcv_buf) + return -1; + + return ops->prepare_rcv_buf(dma, dst, size); +} + +int dma_receive(struct dma *dma, void **dst, void *metadata) +{ + struct dma_ops *ops = dma_dev_ops(dma->dev); + + debug("%s(dma=%p)\n", __func__, dma); + + if (!ops->receive) + return -ENOSYS; + + return ops->receive(dma, dst, metadata); +} + +int dma_send(struct dma *dma, void *src, size_t len, void *metadata) +{ + struct dma_ops *ops = dma_dev_ops(dma->dev); + + debug("%s(dma=%p)\n", __func__, dma); + + if (!ops->send) + return -ENOSYS; + + return ops->send(dma, src, len, metadata); +} +#endif /* CONFIG_DMA_CHANNELS */ + int dma_get_device(u32 transfer_type, struct udevice **devp) { struct udevice *dev; diff --git a/include/dma-uclass.h b/include/dma-uclass.h index 7bec5d3399..16fc879a5c 100644 --- a/include/dma-uclass.h +++ b/include/dma-uclass.h @@ -1,7 +1,7 @@ /* SPDX-License-Identifier: GPL-2.0+ */ /* * Copyright (C) 2018 Álvaro Fernández Rojas noltari@gmail.com - * Copyright (C) 2015 Texas Instruments Incorporated <www.ti.com> + * Copyright (C) 2015 - 2018 Texas Instruments Incorporated <www.ti.com> * Written by Mugunthan V N mugunthanvnm@ti.com * */ @@ -13,6 +13,8 @@
#include <dma.h>
+struct ofnode_phandle_args; + /* * struct dma_ops - Driver model DMA operations * @@ -20,6 +22,93 @@ * driver model. */ struct dma_ops { +#ifdef CONFIG_DMA_CHANNELS + /** + * of_xlate - Translate a client's device-tree (OF) DMA specifier. + * + * The DMA core calls this function as the first step in implementing + * a client's dma_get_by_*() call. + * + * If this function pointer is set to NULL, the DMA core will use a + * default implementation, which assumes #dma-cells = <1>, and that + * the DT cell contains a simple integer DMA Channel. + * + * At present, the DMA API solely supports device-tree. If this + * changes, other xxx_xlate() functions may be added to support those + * other mechanisms. + * + * @dma: The dma struct to hold the translation result. + * @args: The dma specifier values from device tree. + * @return 0 if OK, or a negative error code. + */ + int (*of_xlate)(struct dma *dma, + struct ofnode_phandle_args *args); + /** + * request - Request a translated DMA. + * + * The DMA core calls this function as the second step in + * implementing a client's dma_get_by_*() call, following a successful + * xxx_xlate() call, or as the only step in implementing a client's + * dma_request() call. + * + * @dma: The DMA struct to request; this has been filled in by + * a previoux xxx_xlate() function call, or by the caller of + * dma_request(). + * @return 0 if OK, or a negative error code. + */ + int (*request)(struct dma *dma); + /** + * free - Free a previously requested dma. + * + * This is the implementation of the client dma_free() API. + * + * @dma: The DMA to free. + * @return 0 if OK, or a negative error code. + */ + int (*free)(struct dma *dma); + /** + * enable() - Enable a DMA Channel. + * + * @dma: The DMA Channel to manipulate. + * @return zero on success, or -ve error code. + */ + int (*enable)(struct dma *dma); + /** + * disable() - Disable a DMA Channel. + * + * @dma: The DMA Channel to manipulate. + * @return zero on success, or -ve error code. + */ + int (*disable)(struct dma *dma); + /** + * add_rcv_buf() - Prepare/Add receive DMA buffer. + * + * @dma: The DMA Channel to manipulate. + * @dst: The receive buffer pointer. + * @size: The receive buffer size + * @return zero on success, or -ve error code. + */ + int (*prepare_rcv_buf)(struct dma *dma, void *dst, size_t size); + /** + * receive() - Receive a DMA transfer. + * + * @dma: The DMA Channel to manipulate. + * @dst: The destination pointer. + * @metadata: DMA driver's specific data + * @return zero on success, or -ve error code. + */ + int (*receive)(struct dma *dma, void **dst, void *metadata); + /** + * send() - Send a DMA transfer. + * + * @dma: The DMA Channel to manipulate. + * @src: The source pointer. + * @len: Length of the data to be sent (number of bytes). + * @metadata: DMA driver's specific data + * @return zero on success, or -ve error code. + */ + int (*send)(struct dma *dma, void *src, size_t len, void *metadata); +#endif /* CONFIG_DMA_CHANNELS */ /** * transfer() - Issue a DMA transfer. The implementation must * wait until the transfer is done. diff --git a/include/dma.h b/include/dma.h index 97fa0cf695..d1c3d0df7d 100644 --- a/include/dma.h +++ b/include/dma.h @@ -1,12 +1,17 @@ /* SPDX-License-Identifier: GPL-2.0+ */ /* - * (C) Copyright 2015 - * Texas Instruments Incorporated, <www.ti.com> + * Copyright (C) 2018 Álvaro Fernández Rojas noltari@gmail.com + * Copyright (C) 2015 - 2018 Texas Instruments Incorporated <www.ti.com> + * Written by Mugunthan V N mugunthanvnm@ti.com + * */
#ifndef _DMA_H_ #define _DMA_H_
+#include <linux/errno.h> +#include <linux/types.h> + /* * enum dma_direction - dma transfer direction indicator * @DMA_MEM_TO_MEM: Memcpy mode @@ -36,6 +41,257 @@ struct dma_dev_priv { u32 supported; };
+#ifdef CONFIG_DMA_CHANNELS +/** + * A DMA is a feature of computer systems that allows certain hardware + * subsystems to access main system memory, independent of the CPU. + * DMA channels are typically generated externally to the HW module + * consuming them, by an entity this API calls a DMA provider. This API + * provides a standard means for drivers to enable and disable DMAs, and to + * copy, send and receive data using DMA. + * + * A driver that implements UCLASS_DMA is a DMA provider. A provider will + * often implement multiple separate DMAs, since the hardware it manages + * often has this capability. dma_uclass.h describes the interface which + * DMA providers must implement. + * + * DMA consumers/clients are the HW modules driven by the DMA channels. This + * header file describes the API used by drivers for those HW modules. + * + * DMA consumer DMA_MEM_TO_DEV (transmit) usage example (based on networking). + * Note. dma_send() is sync operation always - it'll start transfer and will + * poll for it to complete: + * - get/request dma channel + * struct dma dma_tx; + * ret = dma_get_by_name(common->dev, "tx0", &dma_tx); + * if (ret) ... + * + * - enable dma channel + * ret = dma_enable(&dma_tx); + * if (ret) ... + * + * - dma transmit DMA_MEM_TO_DEV. + * struct ti_drv_packet_data packet_data; + * + * packet_data.opt1 = val1; + * packet_data.opt2 = val2; + * ret = dma_send(&dma_tx, packet, length, &packet_data); + * if (ret) .. + * + * DMA consumer DMA_DEV_TO_MEM (receive) usage example (based on networking). + * Note. dma_receive() is sync operation always - it'll start transfer + * (if required) and will poll for it to complete (or for any previously + * configured dev2mem transfer to complete): + * - get/request dma channel + * struct dma dma_rx; + * ret = dma_get_by_name(common->dev, "rx0", &dma_rx); + * if (ret) ... + * + * - enable dma channel + * ret = dma_enable(&dma_rx); + * if (ret) ... + * + * - dma receive DMA_DEV_TO_MEM. + * struct ti_drv_packet_data packet_data; + * + * len = dma_receive(&dma_rx, (void **)packet, &packet_data); + * if (ret < 0) ... + * + * DMA consumer DMA_DEV_TO_MEM (receive) zero-copy usage example (based on + * networking). Networking subsystem allows to configure and use few receive + * buffers (dev2mem), as Networking RX DMA channels usually implemented + * as streaming interface + * - get/request dma channel + * struct dma dma_rx; + * ret = dma_get_by_name(common->dev, "rx0", &dma_rx); + * if (ret) ... + * + * for (i = 0; i < RX_DESC_NUM; i++) { + * ret = dma_prepare_rcv_buf(&dma_rx, + * net_rx_packets[i], + * RX_BUF_SIZE); + * if (ret) ... + * } + * + * - enable dma channel + * ret = dma_enable(&dma_rx); + * if (ret) ... + * + * - dma receive DMA_DEV_TO_MEM. + * struct ti_drv_packet_data packet_data; + * + * len = dma_receive(&dma_rx, (void **)packet, &packet_data); + * if (ret < 0) .. + * + * -- process packet -- + * + * - return buffer back to DAM channel + * ret = dma_prepare_rcv_buf(&dma_rx, + * net_rx_packets[rx_next], + * RX_BUF_SIZE); + */ + +struct udevice; + +/** + * struct dma - A handle to (allowing control of) a single DMA. + * + * Clients provide storage for DMA handles. The content of the structure is + * managed solely by the DMA API and DMA drivers. A DMA struct is + * initialized by "get"ing the DMA struct. The DMA struct is passed to all + * other DMA APIs to identify which DMA channel to operate upon. + * + * @dev: The device which implements the DMA channel. + * @id: The DMA channel ID within the provider. + * + * Currently, the DMA API assumes that a single integer ID is enough to + * identify and configure any DMA channel for any DMA provider. If this + * assumption becomes invalid in the future, the struct could be expanded to + * either (a) add more fields to allow DMA providers to store additional + * information, or (b) replace the id field with an opaque pointer, which the + * provider would dynamically allocated during its .of_xlate op, and process + * during is .request op. This may require the addition of an extra op to clean + * up the allocation. + */ +struct dma { + struct udevice *dev; + /* + * Written by of_xlate. We assume a single id is enough for now. In the + * future, we might add more fields here. + */ + unsigned long id; +}; + +# if CONFIG_IS_ENABLED(OF_CONTROL) && CONFIG_IS_ENABLED(DMA) +/** + * dma_get_by_index - Get/request a DMA by integer index. + * + * This looks up and requests a DMA. The index is relative to the client + * device; each device is assumed to have n DMAs associated with it somehow, + * and this function finds and requests one of them. The mapping of client + * device DMA indices to provider DMAs may be via device-tree properties, + * board-provided mapping tables, or some other mechanism. + * + * @dev: The client device. + * @index: The index of the DMA to request, within the client's list of + * DMA channels. + * @dma: A pointer to a DMA struct to initialize. + * @return 0 if OK, or a negative error code. + */ +int dma_get_by_index(struct udevice *dev, int index, struct dma *dma); + +/** + * dma_get_by_name - Get/request a DMA by name. + * + * This looks up and requests a DMA. The name is relative to the client + * device; each device is assumed to have n DMAs associated with it somehow, + * and this function finds and requests one of them. The mapping of client + * device DMA names to provider DMAs may be via device-tree properties, + * board-provided mapping tables, or some other mechanism. + * + * @dev: The client device. + * @name: The name of the DMA to request, within the client's list of + * DMA channels. + * @dma: A pointer to a DMA struct to initialize. + * @return 0 if OK, or a negative error code. + */ +int dma_get_by_name(struct udevice *dev, const char *name, struct dma *dma); +# else +static inline int dma_get_by_index(struct udevice *dev, int index, + struct dma *dma) +{ + return -ENOSYS; +} + +static inline int dma_get_by_name(struct udevice *dev, const char *name, + struct dma *dma) +{ + return -ENOSYS; +} +# endif + +/** + * dma_request - Request a DMA by provider-specific ID. + * + * This requests a DMA using a provider-specific ID. Generally, this function + * should not be used, since dma_get_by_index/name() provide an interface that + * better separates clients from intimate knowledge of DMA providers. + * However, this function may be useful in core SoC-specific code. + * + * @dev: The DMA provider device. + * @dma: A pointer to a DMA struct to initialize. The caller must + * have already initialized any field in this struct which the + * DMA provider uses to identify the DMA channel. + * @return 0 if OK, or a negative error code. + */ +int dma_request(struct udevice *dev, struct dma *dma); + +/** + * dma_free - Free a previously requested DMA. + * + * @dma: A DMA struct that was previously successfully requested by + * dma_request/get_by_*(). + * @return 0 if OK, or a negative error code. + */ +int dma_free(struct dma *dma); + +/** + * dma_enable() - Enable (turn on) a DMA channel. + * + * @dma: A DMA struct that was previously successfully requested by + * dma_request/get_by_*(). + * @return zero on success, or -ve error code. + */ +int dma_enable(struct dma *dma); + +/** + * dma_disable() - Disable (turn off) a DMA channel. + * + * @dma: A DMA struct that was previously successfully requested by + * dma_request/get_by_*(). + * @return zero on success, or -ve error code. + */ +int dma_disable(struct dma *dma); + +/** + * dma_prepare_rcv_buf() - Prepare/add receive DMA buffer. + * + * It allows to implement zero-copy async DMA_DEV_TO_MEM (receive) transactions + * if supported by DMA providers. + * + * @dma: A DMA struct that was previously successfully requested by + * dma_request/get_by_*(). + * @dst: The receive buffer pointer. + * @size: The receive buffer size + * @return zero on success, or -ve error code. + */ +int dma_prepare_rcv_buf(struct dma *dma, void *dst, size_t size); + +/** + * dma_receive() - Receive a DMA transfer. + * + * @dma: A DMA struct that was previously successfully requested by + * dma_request/get_by_*(). + * @dst: The destination pointer. + * @metadata: DMA driver's channel specific data + * @return length of received data on success, or zero - no data, + * or -ve error code. + */ +int dma_receive(struct dma *dma, void **dst, void *metadata); + +/** + * dma_send() - Send a DMA transfer. + * + * @dma: A DMA struct that was previously successfully requested by + * dma_request/get_by_*(). + * @src: The source pointer. + * @len: Length of the data to be sent (number of bytes). + * @metadata: DMA driver's channel specific data + * @return zero on success, or -ve error code. + */ +int dma_send(struct dma *dma, void *src, size_t len, void *metadata); +#endif /* CONFIG_DMA_CHANNELS */ + /* * dma_get_device - get a DMA device which supports transfer * type of transfer_type