#
source "drivers/bus/mhi/host/Kconfig"
+source "drivers/bus/mhi/ep/Kconfig"
# Host MHI stack
obj-y += host/
+
+# Endpoint MHI stack
+obj-y += ep/
--- /dev/null
+config MHI_BUS_EP
+ tristate "Modem Host Interface (MHI) bus Endpoint implementation"
+ help
+ Bus driver for MHI protocol. Modem Host Interface (MHI) is a
+ communication protocol used by a host processor to control
+ and communicate a modem device over a high speed peripheral
+ bus or shared memory.
+
+ MHI_BUS_EP implements the MHI protocol for the endpoint devices,
+ such as SDX55 modem connected to the host machine over PCIe.
--- /dev/null
+obj-$(CONFIG_MHI_BUS_EP) += mhi_ep.o
+mhi_ep-y := main.o
--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2022, Linaro Ltd.
+ *
+ */
+
+#ifndef _MHI_EP_INTERNAL_
+#define _MHI_EP_INTERNAL_
+
+#include <linux/bitfield.h>
+
+#include "../common.h"
+
+extern struct bus_type mhi_ep_bus_type;
+
+#define MHI_REG_OFFSET 0x100
+#define BHI_REG_OFFSET 0x200
+
+/* MHI registers */
+#define EP_MHIREGLEN (MHI_REG_OFFSET + MHIREGLEN)
+#define EP_MHIVER (MHI_REG_OFFSET + MHIVER)
+#define EP_MHICFG (MHI_REG_OFFSET + MHICFG)
+#define EP_CHDBOFF (MHI_REG_OFFSET + CHDBOFF)
+#define EP_ERDBOFF (MHI_REG_OFFSET + ERDBOFF)
+#define EP_BHIOFF (MHI_REG_OFFSET + BHIOFF)
+#define EP_BHIEOFF (MHI_REG_OFFSET + BHIEOFF)
+#define EP_DEBUGOFF (MHI_REG_OFFSET + DEBUGOFF)
+#define EP_MHICTRL (MHI_REG_OFFSET + MHICTRL)
+#define EP_MHISTATUS (MHI_REG_OFFSET + MHISTATUS)
+#define EP_CCABAP_LOWER (MHI_REG_OFFSET + CCABAP_LOWER)
+#define EP_CCABAP_HIGHER (MHI_REG_OFFSET + CCABAP_HIGHER)
+#define EP_ECABAP_LOWER (MHI_REG_OFFSET + ECABAP_LOWER)
+#define EP_ECABAP_HIGHER (MHI_REG_OFFSET + ECABAP_HIGHER)
+#define EP_CRCBAP_LOWER (MHI_REG_OFFSET + CRCBAP_LOWER)
+#define EP_CRCBAP_HIGHER (MHI_REG_OFFSET + CRCBAP_HIGHER)
+#define EP_CRDB_LOWER (MHI_REG_OFFSET + CRDB_LOWER)
+#define EP_CRDB_HIGHER (MHI_REG_OFFSET + CRDB_HIGHER)
+#define EP_MHICTRLBASE_LOWER (MHI_REG_OFFSET + MHICTRLBASE_LOWER)
+#define EP_MHICTRLBASE_HIGHER (MHI_REG_OFFSET + MHICTRLBASE_HIGHER)
+#define EP_MHICTRLLIMIT_LOWER (MHI_REG_OFFSET + MHICTRLLIMIT_LOWER)
+#define EP_MHICTRLLIMIT_HIGHER (MHI_REG_OFFSET + MHICTRLLIMIT_HIGHER)
+#define EP_MHIDATABASE_LOWER (MHI_REG_OFFSET + MHIDATABASE_LOWER)
+#define EP_MHIDATABASE_HIGHER (MHI_REG_OFFSET + MHIDATABASE_HIGHER)
+#define EP_MHIDATALIMIT_LOWER (MHI_REG_OFFSET + MHIDATALIMIT_LOWER)
+#define EP_MHIDATALIMIT_HIGHER (MHI_REG_OFFSET + MHIDATALIMIT_HIGHER)
+
+/* MHI BHI registers */
+#define EP_BHI_INTVEC (BHI_REG_OFFSET + BHI_INTVEC)
+#define EP_BHI_EXECENV (BHI_REG_OFFSET + BHI_EXECENV)
+
+/* MHI Doorbell registers */
+#define CHDB_LOWER_n(n) (0x400 + 0x8 * (n))
+#define CHDB_HIGHER_n(n) (0x404 + 0x8 * (n))
+#define ERDB_LOWER_n(n) (0x800 + 0x8 * (n))
+#define ERDB_HIGHER_n(n) (0x804 + 0x8 * (n))
+
+#define MHI_CTRL_INT_STATUS 0x4
+#define MHI_CTRL_INT_STATUS_MSK BIT(0)
+#define MHI_CTRL_INT_STATUS_CRDB_MSK BIT(1)
+#define MHI_CHDB_INT_STATUS_n(n) (0x28 + 0x4 * (n))
+#define MHI_ERDB_INT_STATUS_n(n) (0x38 + 0x4 * (n))
+
+#define MHI_CTRL_INT_CLEAR 0x4c
+#define MHI_CTRL_INT_MMIO_WR_CLEAR BIT(2)
+#define MHI_CTRL_INT_CRDB_CLEAR BIT(1)
+#define MHI_CTRL_INT_CRDB_MHICTRL_CLEAR BIT(0)
+
+#define MHI_CHDB_INT_CLEAR_n(n) (0x70 + 0x4 * (n))
+#define MHI_CHDB_INT_CLEAR_n_CLEAR_ALL GENMASK(31, 0)
+#define MHI_ERDB_INT_CLEAR_n(n) (0x80 + 0x4 * (n))
+#define MHI_ERDB_INT_CLEAR_n_CLEAR_ALL GENMASK(31, 0)
+
+/*
+ * Unlike the usual "masking" convention, writing "1" to a bit in this register
+ * enables the interrupt and writing "0" will disable it..
+ */
+#define MHI_CTRL_INT_MASK 0x94
+#define MHI_CTRL_INT_MASK_MASK GENMASK(1, 0)
+#define MHI_CTRL_MHICTRL_MASK BIT(0)
+#define MHI_CTRL_CRDB_MASK BIT(1)
+
+#define MHI_CHDB_INT_MASK_n(n) (0xb8 + 0x4 * (n))
+#define MHI_CHDB_INT_MASK_n_EN_ALL GENMASK(31, 0)
+#define MHI_ERDB_INT_MASK_n(n) (0xc8 + 0x4 * (n))
+#define MHI_ERDB_INT_MASK_n_EN_ALL GENMASK(31, 0)
+
+#define NR_OF_CMD_RINGS 1
+#define MHI_MASK_ROWS_CH_DB 4
+#define MHI_MASK_ROWS_EV_DB 4
+#define MHI_MASK_CH_LEN 32
+#define MHI_MASK_EV_LEN 32
+
+/* Generic context */
+struct mhi_generic_ctx {
+ __le32 reserved0;
+ __le32 reserved1;
+ __le32 reserved2;
+
+ __le64 rbase __packed __aligned(4);
+ __le64 rlen __packed __aligned(4);
+ __le64 rp __packed __aligned(4);
+ __le64 wp __packed __aligned(4);
+};
+
+enum mhi_ep_ring_type {
+ RING_TYPE_CMD,
+ RING_TYPE_ER,
+ RING_TYPE_CH,
+};
+
+/* Ring element */
+union mhi_ep_ring_ctx {
+ struct mhi_cmd_ctxt cmd;
+ struct mhi_event_ctxt ev;
+ struct mhi_chan_ctxt ch;
+ struct mhi_generic_ctx generic;
+};
+
+struct mhi_ep_ring {
+ struct mhi_ep_cntrl *mhi_cntrl;
+ union mhi_ep_ring_ctx *ring_ctx;
+ struct mhi_ring_element *ring_cache;
+ enum mhi_ep_ring_type type;
+ u64 rbase;
+ size_t rd_offset;
+ size_t wr_offset;
+ size_t ring_size;
+ u32 db_offset_h;
+ u32 db_offset_l;
+ u32 ch_id;
+};
+
+struct mhi_ep_cmd {
+ struct mhi_ep_ring ring;
+};
+
+struct mhi_ep_event {
+ struct mhi_ep_ring ring;
+};
+
+struct mhi_ep_chan {
+ char *name;
+ struct mhi_ep_device *mhi_dev;
+ struct mhi_ep_ring ring;
+ struct mutex lock;
+ void (*xfer_cb)(struct mhi_ep_device *mhi_dev, struct mhi_result *result);
+ enum mhi_ch_state state;
+ enum dma_data_direction dir;
+ u64 tre_loc;
+ u32 tre_size;
+ u32 tre_bytes_left;
+ u32 chan;
+ bool skip_td;
+};
+
+#endif
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MHI Endpoint bus stack
+ *
+ * Copyright (C) 2022 Linaro Ltd.
+ * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/dma-direction.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mhi_ep.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include "internal.h"
+
+static DEFINE_IDA(mhi_ep_cntrl_ida);
+
+static void mhi_ep_release_device(struct device *dev)
+{
+ struct mhi_ep_device *mhi_dev = to_mhi_ep_device(dev);
+
+ if (mhi_dev->dev_type == MHI_DEVICE_CONTROLLER)
+ mhi_dev->mhi_cntrl->mhi_dev = NULL;
+
+ /*
+ * We need to set the mhi_chan->mhi_dev to NULL here since the MHI
+ * devices for the channels will only get created in mhi_ep_create_device()
+ * if the mhi_dev associated with it is NULL.
+ */
+ if (mhi_dev->ul_chan)
+ mhi_dev->ul_chan->mhi_dev = NULL;
+
+ if (mhi_dev->dl_chan)
+ mhi_dev->dl_chan->mhi_dev = NULL;
+
+ kfree(mhi_dev);
+}
+
+static struct mhi_ep_device *mhi_ep_alloc_device(struct mhi_ep_cntrl *mhi_cntrl,
+ enum mhi_device_type dev_type)
+{
+ struct mhi_ep_device *mhi_dev;
+ struct device *dev;
+
+ mhi_dev = kzalloc(sizeof(*mhi_dev), GFP_KERNEL);
+ if (!mhi_dev)
+ return ERR_PTR(-ENOMEM);
+
+ dev = &mhi_dev->dev;
+ device_initialize(dev);
+ dev->bus = &mhi_ep_bus_type;
+ dev->release = mhi_ep_release_device;
+
+ /* Controller device is always allocated first */
+ if (dev_type == MHI_DEVICE_CONTROLLER)
+ /* for MHI controller device, parent is the bus device (e.g. PCI EPF) */
+ dev->parent = mhi_cntrl->cntrl_dev;
+ else
+ /* for MHI client devices, parent is the MHI controller device */
+ dev->parent = &mhi_cntrl->mhi_dev->dev;
+
+ mhi_dev->mhi_cntrl = mhi_cntrl;
+ mhi_dev->dev_type = dev_type;
+
+ return mhi_dev;
+}
+
+static int mhi_ep_chan_init(struct mhi_ep_cntrl *mhi_cntrl,
+ const struct mhi_ep_cntrl_config *config)
+{
+ const struct mhi_ep_channel_config *ch_cfg;
+ struct device *dev = mhi_cntrl->cntrl_dev;
+ u32 chan, i;
+ int ret = -EINVAL;
+
+ mhi_cntrl->max_chan = config->max_channels;
+
+ /*
+ * Allocate max_channels supported by the MHI endpoint and populate
+ * only the defined channels
+ */
+ mhi_cntrl->mhi_chan = kcalloc(mhi_cntrl->max_chan, sizeof(*mhi_cntrl->mhi_chan),
+ GFP_KERNEL);
+ if (!mhi_cntrl->mhi_chan)
+ return -ENOMEM;
+
+ for (i = 0; i < config->num_channels; i++) {
+ struct mhi_ep_chan *mhi_chan;
+
+ ch_cfg = &config->ch_cfg[i];
+
+ chan = ch_cfg->num;
+ if (chan >= mhi_cntrl->max_chan) {
+ dev_err(dev, "Channel (%u) exceeds maximum available channels (%u)\n",
+ chan, mhi_cntrl->max_chan);
+ goto error_chan_cfg;
+ }
+
+ /* Bi-directional and direction less channels are not supported */
+ if (ch_cfg->dir == DMA_BIDIRECTIONAL || ch_cfg->dir == DMA_NONE) {
+ dev_err(dev, "Invalid direction (%u) for channel (%u)\n",
+ ch_cfg->dir, chan);
+ goto error_chan_cfg;
+ }
+
+ mhi_chan = &mhi_cntrl->mhi_chan[chan];
+ mhi_chan->name = ch_cfg->name;
+ mhi_chan->chan = chan;
+ mhi_chan->dir = ch_cfg->dir;
+ mutex_init(&mhi_chan->lock);
+ }
+
+ return 0;
+
+error_chan_cfg:
+ kfree(mhi_cntrl->mhi_chan);
+
+ return ret;
+}
+
+/*
+ * Allocate channel and command rings here. Event rings will be allocated
+ * in mhi_ep_power_up() as the config comes from the host.
+ */
+int mhi_ep_register_controller(struct mhi_ep_cntrl *mhi_cntrl,
+ const struct mhi_ep_cntrl_config *config)
+{
+ struct mhi_ep_device *mhi_dev;
+ int ret;
+
+ if (!mhi_cntrl || !mhi_cntrl->cntrl_dev)
+ return -EINVAL;
+
+ ret = mhi_ep_chan_init(mhi_cntrl, config);
+ if (ret)
+ return ret;
+
+ mhi_cntrl->mhi_cmd = kcalloc(NR_OF_CMD_RINGS, sizeof(*mhi_cntrl->mhi_cmd), GFP_KERNEL);
+ if (!mhi_cntrl->mhi_cmd) {
+ ret = -ENOMEM;
+ goto err_free_ch;
+ }
+
+ /* Set controller index */
+ ret = ida_alloc(&mhi_ep_cntrl_ida, GFP_KERNEL);
+ if (ret < 0)
+ goto err_free_cmd;
+
+ mhi_cntrl->index = ret;
+
+ /* Allocate the controller device */
+ mhi_dev = mhi_ep_alloc_device(mhi_cntrl, MHI_DEVICE_CONTROLLER);
+ if (IS_ERR(mhi_dev)) {
+ dev_err(mhi_cntrl->cntrl_dev, "Failed to allocate controller device\n");
+ ret = PTR_ERR(mhi_dev);
+ goto err_ida_free;
+ }
+
+ dev_set_name(&mhi_dev->dev, "mhi_ep%u", mhi_cntrl->index);
+ mhi_dev->name = dev_name(&mhi_dev->dev);
+ mhi_cntrl->mhi_dev = mhi_dev;
+
+ ret = device_add(&mhi_dev->dev);
+ if (ret)
+ goto err_put_dev;
+
+ dev_dbg(&mhi_dev->dev, "MHI EP Controller registered\n");
+
+ return 0;
+
+err_put_dev:
+ put_device(&mhi_dev->dev);
+err_ida_free:
+ ida_free(&mhi_ep_cntrl_ida, mhi_cntrl->index);
+err_free_cmd:
+ kfree(mhi_cntrl->mhi_cmd);
+err_free_ch:
+ kfree(mhi_cntrl->mhi_chan);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(mhi_ep_register_controller);
+
+void mhi_ep_unregister_controller(struct mhi_ep_cntrl *mhi_cntrl)
+{
+ struct mhi_ep_device *mhi_dev = mhi_cntrl->mhi_dev;
+
+ kfree(mhi_cntrl->mhi_cmd);
+ kfree(mhi_cntrl->mhi_chan);
+
+ device_del(&mhi_dev->dev);
+ put_device(&mhi_dev->dev);
+
+ ida_free(&mhi_ep_cntrl_ida, mhi_cntrl->index);
+}
+EXPORT_SYMBOL_GPL(mhi_ep_unregister_controller);
+
+static int mhi_ep_match(struct device *dev, struct device_driver *drv)
+{
+ struct mhi_ep_device *mhi_dev = to_mhi_ep_device(dev);
+
+ /*
+ * If the device is a controller type then there is no client driver
+ * associated with it
+ */
+ if (mhi_dev->dev_type == MHI_DEVICE_CONTROLLER)
+ return 0;
+
+ return 0;
+};
+
+struct bus_type mhi_ep_bus_type = {
+ .name = "mhi_ep",
+ .dev_name = "mhi_ep",
+ .match = mhi_ep_match,
+};
+
+static int __init mhi_ep_init(void)
+{
+ return bus_register(&mhi_ep_bus_type);
+}
+
+static void __exit mhi_ep_exit(void)
+{
+ bus_unregister(&mhi_ep_bus_type);
+}
+
+postcore_initcall(mhi_ep_init);
+module_exit(mhi_ep_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MHI Bus Endpoint stack");
+MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2022, Linaro Ltd.
+ *
+ */
+#ifndef _MHI_EP_H_
+#define _MHI_EP_H_
+
+#include <linux/dma-direction.h>
+#include <linux/mhi.h>
+
+#define MHI_EP_DEFAULT_MTU 0x8000
+
+/**
+ * struct mhi_ep_channel_config - Channel configuration structure for controller
+ * @name: The name of this channel
+ * @num: The number assigned to this channel
+ * @num_elements: The number of elements that can be queued to this channel
+ * @dir: Direction that data may flow on this channel
+ */
+struct mhi_ep_channel_config {
+ char *name;
+ u32 num;
+ u32 num_elements;
+ enum dma_data_direction dir;
+};
+
+/**
+ * struct mhi_ep_cntrl_config - MHI Endpoint controller configuration
+ * @mhi_version: MHI spec version supported by the controller
+ * @max_channels: Maximum number of channels supported
+ * @num_channels: Number of channels defined in @ch_cfg
+ * @ch_cfg: Array of defined channels
+ */
+struct mhi_ep_cntrl_config {
+ u32 mhi_version;
+ u32 max_channels;
+ u32 num_channels;
+ const struct mhi_ep_channel_config *ch_cfg;
+};
+
+/**
+ * struct mhi_ep_db_info - MHI Endpoint doorbell info
+ * @mask: Mask of the doorbell interrupt
+ * @status: Status of the doorbell interrupt
+ */
+struct mhi_ep_db_info {
+ u32 mask;
+ u32 status;
+};
+
+/**
+ * struct mhi_ep_cntrl - MHI Endpoint controller structure
+ * @cntrl_dev: Pointer to the struct device of physical bus acting as the MHI
+ * Endpoint controller
+ * @mhi_dev: MHI Endpoint device instance for the controller
+ * @mmio: MMIO region containing the MHI registers
+ * @mhi_chan: Points to the channel configuration table
+ * @mhi_event: Points to the event ring configurations table
+ * @mhi_cmd: Points to the command ring configurations table
+ * @sm: MHI Endpoint state machine
+ * @raise_irq: CB function for raising IRQ to the host
+ * @alloc_map: CB function for allocating memory in endpoint for storing host context and mapping it
+ * @unmap_free: CB function to unmap and free the allocated memory in endpoint for storing host context
+ * @read_from_host: CB function for reading from host memory from endpoint
+ * @write_to_host: CB function for writing to host memory from endpoint
+ * @mhi_state: MHI Endpoint state
+ * @max_chan: Maximum channels supported by the endpoint controller
+ * @mru: MRU (Maximum Receive Unit) value of the endpoint controller
+ * @index: MHI Endpoint controller index
+ */
+struct mhi_ep_cntrl {
+ struct device *cntrl_dev;
+ struct mhi_ep_device *mhi_dev;
+ void __iomem *mmio;
+
+ struct mhi_ep_chan *mhi_chan;
+ struct mhi_ep_event *mhi_event;
+ struct mhi_ep_cmd *mhi_cmd;
+ struct mhi_ep_sm *sm;
+
+ void (*raise_irq)(struct mhi_ep_cntrl *mhi_cntrl, u32 vector);
+ int (*alloc_map)(struct mhi_ep_cntrl *mhi_cntrl, u64 pci_addr, phys_addr_t *phys_ptr,
+ void __iomem **virt, size_t size);
+ void (*unmap_free)(struct mhi_ep_cntrl *mhi_cntrl, u64 pci_addr, phys_addr_t phys,
+ void __iomem *virt, size_t size);
+ int (*read_from_host)(struct mhi_ep_cntrl *mhi_cntrl, u64 from, void *to, size_t size);
+ int (*write_to_host)(struct mhi_ep_cntrl *mhi_cntrl, void *from, u64 to, size_t size);
+
+ enum mhi_state mhi_state;
+
+ u32 max_chan;
+ u32 mru;
+ u32 index;
+};
+
+/**
+ * struct mhi_ep_device - Structure representing an MHI Endpoint device that binds
+ * to channels or is associated with controllers
+ * @dev: Driver model device node for the MHI Endpoint device
+ * @mhi_cntrl: Controller the device belongs to
+ * @id: Pointer to MHI Endpoint device ID struct
+ * @name: Name of the associated MHI Endpoint device
+ * @ul_chan: UL channel for the device
+ * @dl_chan: DL channel for the device
+ * @dev_type: MHI device type
+ */
+struct mhi_ep_device {
+ struct device dev;
+ struct mhi_ep_cntrl *mhi_cntrl;
+ const struct mhi_device_id *id;
+ const char *name;
+ struct mhi_ep_chan *ul_chan;
+ struct mhi_ep_chan *dl_chan;
+ enum mhi_device_type dev_type;
+};
+
+#define to_mhi_ep_device(dev) container_of(dev, struct mhi_ep_device, dev)
+
+/**
+ * mhi_ep_register_controller - Register MHI Endpoint controller
+ * @mhi_cntrl: MHI Endpoint controller to register
+ * @config: Configuration to use for the controller
+ *
+ * Return: 0 if controller registrations succeeds, a negative error code otherwise.
+ */
+int mhi_ep_register_controller(struct mhi_ep_cntrl *mhi_cntrl,
+ const struct mhi_ep_cntrl_config *config);
+
+/**
+ * mhi_ep_unregister_controller - Unregister MHI Endpoint controller
+ * @mhi_cntrl: MHI Endpoint controller to unregister
+ */
+void mhi_ep_unregister_controller(struct mhi_ep_cntrl *mhi_cntrl);
+
+#endif
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