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0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Thunderbolt driver - control channel and configuration commands
0004  *
0005  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
0006  * Copyright (C) 2018, Intel Corporation
0007  */
0008 
0009 #include <linux/crc32.h>
0010 #include <linux/delay.h>
0011 #include <linux/slab.h>
0012 #include <linux/pci.h>
0013 #include <linux/dmapool.h>
0014 #include <linux/workqueue.h>
0015 
0016 #include "ctl.h"
0017 
0018 
0019 #define TB_CTL_RX_PKG_COUNT 10
0020 #define TB_CTL_RETRIES      4
0021 
0022 /**
0023  * struct tb_ctl - Thunderbolt control channel
0024  * @nhi: Pointer to the NHI structure
0025  * @tx: Transmit ring
0026  * @rx: Receive ring
0027  * @frame_pool: DMA pool for control messages
0028  * @rx_packets: Received control messages
0029  * @request_queue_lock: Lock protecting @request_queue
0030  * @request_queue: List of outstanding requests
0031  * @running: Is the control channel running at the moment
0032  * @timeout_msec: Default timeout for non-raw control messages
0033  * @callback: Callback called when hotplug message is received
0034  * @callback_data: Data passed to @callback
0035  */
0036 struct tb_ctl {
0037     struct tb_nhi *nhi;
0038     struct tb_ring *tx;
0039     struct tb_ring *rx;
0040 
0041     struct dma_pool *frame_pool;
0042     struct ctl_pkg *rx_packets[TB_CTL_RX_PKG_COUNT];
0043     struct mutex request_queue_lock;
0044     struct list_head request_queue;
0045     bool running;
0046 
0047     int timeout_msec;
0048     event_cb callback;
0049     void *callback_data;
0050 };
0051 
0052 
0053 #define tb_ctl_WARN(ctl, format, arg...) \
0054     dev_WARN(&(ctl)->nhi->pdev->dev, format, ## arg)
0055 
0056 #define tb_ctl_err(ctl, format, arg...) \
0057     dev_err(&(ctl)->nhi->pdev->dev, format, ## arg)
0058 
0059 #define tb_ctl_warn(ctl, format, arg...) \
0060     dev_warn(&(ctl)->nhi->pdev->dev, format, ## arg)
0061 
0062 #define tb_ctl_info(ctl, format, arg...) \
0063     dev_info(&(ctl)->nhi->pdev->dev, format, ## arg)
0064 
0065 #define tb_ctl_dbg(ctl, format, arg...) \
0066     dev_dbg(&(ctl)->nhi->pdev->dev, format, ## arg)
0067 
0068 static DECLARE_WAIT_QUEUE_HEAD(tb_cfg_request_cancel_queue);
0069 /* Serializes access to request kref_get/put */
0070 static DEFINE_MUTEX(tb_cfg_request_lock);
0071 
0072 /**
0073  * tb_cfg_request_alloc() - Allocates a new config request
0074  *
0075  * This is refcounted object so when you are done with this, call
0076  * tb_cfg_request_put() to it.
0077  */
0078 struct tb_cfg_request *tb_cfg_request_alloc(void)
0079 {
0080     struct tb_cfg_request *req;
0081 
0082     req = kzalloc(sizeof(*req), GFP_KERNEL);
0083     if (!req)
0084         return NULL;
0085 
0086     kref_init(&req->kref);
0087 
0088     return req;
0089 }
0090 
0091 /**
0092  * tb_cfg_request_get() - Increase refcount of a request
0093  * @req: Request whose refcount is increased
0094  */
0095 void tb_cfg_request_get(struct tb_cfg_request *req)
0096 {
0097     mutex_lock(&tb_cfg_request_lock);
0098     kref_get(&req->kref);
0099     mutex_unlock(&tb_cfg_request_lock);
0100 }
0101 
0102 static void tb_cfg_request_destroy(struct kref *kref)
0103 {
0104     struct tb_cfg_request *req = container_of(kref, typeof(*req), kref);
0105 
0106     kfree(req);
0107 }
0108 
0109 /**
0110  * tb_cfg_request_put() - Decrease refcount and possibly release the request
0111  * @req: Request whose refcount is decreased
0112  *
0113  * Call this function when you are done with the request. When refcount
0114  * goes to %0 the object is released.
0115  */
0116 void tb_cfg_request_put(struct tb_cfg_request *req)
0117 {
0118     mutex_lock(&tb_cfg_request_lock);
0119     kref_put(&req->kref, tb_cfg_request_destroy);
0120     mutex_unlock(&tb_cfg_request_lock);
0121 }
0122 
0123 static int tb_cfg_request_enqueue(struct tb_ctl *ctl,
0124                   struct tb_cfg_request *req)
0125 {
0126     WARN_ON(test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags));
0127     WARN_ON(req->ctl);
0128 
0129     mutex_lock(&ctl->request_queue_lock);
0130     if (!ctl->running) {
0131         mutex_unlock(&ctl->request_queue_lock);
0132         return -ENOTCONN;
0133     }
0134     req->ctl = ctl;
0135     list_add_tail(&req->list, &ctl->request_queue);
0136     set_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
0137     mutex_unlock(&ctl->request_queue_lock);
0138     return 0;
0139 }
0140 
0141 static void tb_cfg_request_dequeue(struct tb_cfg_request *req)
0142 {
0143     struct tb_ctl *ctl = req->ctl;
0144 
0145     mutex_lock(&ctl->request_queue_lock);
0146     list_del(&req->list);
0147     clear_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
0148     if (test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
0149         wake_up(&tb_cfg_request_cancel_queue);
0150     mutex_unlock(&ctl->request_queue_lock);
0151 }
0152 
0153 static bool tb_cfg_request_is_active(struct tb_cfg_request *req)
0154 {
0155     return test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
0156 }
0157 
0158 static struct tb_cfg_request *
0159 tb_cfg_request_find(struct tb_ctl *ctl, struct ctl_pkg *pkg)
0160 {
0161     struct tb_cfg_request *req = NULL, *iter;
0162 
0163     mutex_lock(&pkg->ctl->request_queue_lock);
0164     list_for_each_entry(iter, &pkg->ctl->request_queue, list) {
0165         tb_cfg_request_get(iter);
0166         if (iter->match(iter, pkg)) {
0167             req = iter;
0168             break;
0169         }
0170         tb_cfg_request_put(iter);
0171     }
0172     mutex_unlock(&pkg->ctl->request_queue_lock);
0173 
0174     return req;
0175 }
0176 
0177 /* utility functions */
0178 
0179 
0180 static int check_header(const struct ctl_pkg *pkg, u32 len,
0181             enum tb_cfg_pkg_type type, u64 route)
0182 {
0183     struct tb_cfg_header *header = pkg->buffer;
0184 
0185     /* check frame, TODO: frame flags */
0186     if (WARN(len != pkg->frame.size,
0187             "wrong framesize (expected %#x, got %#x)\n",
0188             len, pkg->frame.size))
0189         return -EIO;
0190     if (WARN(type != pkg->frame.eof, "wrong eof (expected %#x, got %#x)\n",
0191             type, pkg->frame.eof))
0192         return -EIO;
0193     if (WARN(pkg->frame.sof, "wrong sof (expected 0x0, got %#x)\n",
0194             pkg->frame.sof))
0195         return -EIO;
0196 
0197     /* check header */
0198     if (WARN(header->unknown != 1 << 9,
0199             "header->unknown is %#x\n", header->unknown))
0200         return -EIO;
0201     if (WARN(route != tb_cfg_get_route(header),
0202             "wrong route (expected %llx, got %llx)",
0203             route, tb_cfg_get_route(header)))
0204         return -EIO;
0205     return 0;
0206 }
0207 
0208 static int check_config_address(struct tb_cfg_address addr,
0209                 enum tb_cfg_space space, u32 offset,
0210                 u32 length)
0211 {
0212     if (WARN(addr.zero, "addr.zero is %#x\n", addr.zero))
0213         return -EIO;
0214     if (WARN(space != addr.space, "wrong space (expected %x, got %x\n)",
0215             space, addr.space))
0216         return -EIO;
0217     if (WARN(offset != addr.offset, "wrong offset (expected %x, got %x\n)",
0218             offset, addr.offset))
0219         return -EIO;
0220     if (WARN(length != addr.length, "wrong space (expected %x, got %x\n)",
0221             length, addr.length))
0222         return -EIO;
0223     /*
0224      * We cannot check addr->port as it is set to the upstream port of the
0225      * sender.
0226      */
0227     return 0;
0228 }
0229 
0230 static struct tb_cfg_result decode_error(const struct ctl_pkg *response)
0231 {
0232     struct cfg_error_pkg *pkg = response->buffer;
0233     struct tb_ctl *ctl = response->ctl;
0234     struct tb_cfg_result res = { 0 };
0235     res.response_route = tb_cfg_get_route(&pkg->header);
0236     res.response_port = 0;
0237     res.err = check_header(response, sizeof(*pkg), TB_CFG_PKG_ERROR,
0238                    tb_cfg_get_route(&pkg->header));
0239     if (res.err)
0240         return res;
0241 
0242     if (pkg->zero1)
0243         tb_ctl_warn(ctl, "pkg->zero1 is %#x\n", pkg->zero1);
0244     if (pkg->zero2)
0245         tb_ctl_warn(ctl, "pkg->zero2 is %#x\n", pkg->zero2);
0246     if (pkg->zero3)
0247         tb_ctl_warn(ctl, "pkg->zero3 is %#x\n", pkg->zero3);
0248 
0249     res.err = 1;
0250     res.tb_error = pkg->error;
0251     res.response_port = pkg->port;
0252     return res;
0253 
0254 }
0255 
0256 static struct tb_cfg_result parse_header(const struct ctl_pkg *pkg, u32 len,
0257                      enum tb_cfg_pkg_type type, u64 route)
0258 {
0259     struct tb_cfg_header *header = pkg->buffer;
0260     struct tb_cfg_result res = { 0 };
0261 
0262     if (pkg->frame.eof == TB_CFG_PKG_ERROR)
0263         return decode_error(pkg);
0264 
0265     res.response_port = 0; /* will be updated later for cfg_read/write */
0266     res.response_route = tb_cfg_get_route(header);
0267     res.err = check_header(pkg, len, type, route);
0268     return res;
0269 }
0270 
0271 static void tb_cfg_print_error(struct tb_ctl *ctl,
0272                    const struct tb_cfg_result *res)
0273 {
0274     WARN_ON(res->err != 1);
0275     switch (res->tb_error) {
0276     case TB_CFG_ERROR_PORT_NOT_CONNECTED:
0277         /* Port is not connected. This can happen during surprise
0278          * removal. Do not warn. */
0279         return;
0280     case TB_CFG_ERROR_INVALID_CONFIG_SPACE:
0281         /*
0282          * Invalid cfg_space/offset/length combination in
0283          * cfg_read/cfg_write.
0284          */
0285         tb_ctl_dbg(ctl, "%llx:%x: invalid config space or offset\n",
0286                res->response_route, res->response_port);
0287         return;
0288     case TB_CFG_ERROR_NO_SUCH_PORT:
0289         /*
0290          * - The route contains a non-existent port.
0291          * - The route contains a non-PHY port (e.g. PCIe).
0292          * - The port in cfg_read/cfg_write does not exist.
0293          */
0294         tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Invalid port\n",
0295             res->response_route, res->response_port);
0296         return;
0297     case TB_CFG_ERROR_LOOP:
0298         tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Route contains a loop\n",
0299             res->response_route, res->response_port);
0300         return;
0301     case TB_CFG_ERROR_LOCK:
0302         tb_ctl_warn(ctl, "%llx:%x: downstream port is locked\n",
0303                 res->response_route, res->response_port);
0304         return;
0305     default:
0306         /* 5,6,7,9 and 11 are also valid error codes */
0307         tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Unknown error\n",
0308             res->response_route, res->response_port);
0309         return;
0310     }
0311 }
0312 
0313 static __be32 tb_crc(const void *data, size_t len)
0314 {
0315     return cpu_to_be32(~__crc32c_le(~0, data, len));
0316 }
0317 
0318 static void tb_ctl_pkg_free(struct ctl_pkg *pkg)
0319 {
0320     if (pkg) {
0321         dma_pool_free(pkg->ctl->frame_pool,
0322                   pkg->buffer, pkg->frame.buffer_phy);
0323         kfree(pkg);
0324     }
0325 }
0326 
0327 static struct ctl_pkg *tb_ctl_pkg_alloc(struct tb_ctl *ctl)
0328 {
0329     struct ctl_pkg *pkg = kzalloc(sizeof(*pkg), GFP_KERNEL);
0330     if (!pkg)
0331         return NULL;
0332     pkg->ctl = ctl;
0333     pkg->buffer = dma_pool_alloc(ctl->frame_pool, GFP_KERNEL,
0334                      &pkg->frame.buffer_phy);
0335     if (!pkg->buffer) {
0336         kfree(pkg);
0337         return NULL;
0338     }
0339     return pkg;
0340 }
0341 
0342 
0343 /* RX/TX handling */
0344 
0345 static void tb_ctl_tx_callback(struct tb_ring *ring, struct ring_frame *frame,
0346                    bool canceled)
0347 {
0348     struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
0349     tb_ctl_pkg_free(pkg);
0350 }
0351 
0352 /*
0353  * tb_cfg_tx() - transmit a packet on the control channel
0354  *
0355  * len must be a multiple of four.
0356  *
0357  * Return: Returns 0 on success or an error code on failure.
0358  */
0359 static int tb_ctl_tx(struct tb_ctl *ctl, const void *data, size_t len,
0360              enum tb_cfg_pkg_type type)
0361 {
0362     int res;
0363     struct ctl_pkg *pkg;
0364     if (len % 4 != 0) { /* required for le->be conversion */
0365         tb_ctl_WARN(ctl, "TX: invalid size: %zu\n", len);
0366         return -EINVAL;
0367     }
0368     if (len > TB_FRAME_SIZE - 4) { /* checksum is 4 bytes */
0369         tb_ctl_WARN(ctl, "TX: packet too large: %zu/%d\n",
0370                 len, TB_FRAME_SIZE - 4);
0371         return -EINVAL;
0372     }
0373     pkg = tb_ctl_pkg_alloc(ctl);
0374     if (!pkg)
0375         return -ENOMEM;
0376     pkg->frame.callback = tb_ctl_tx_callback;
0377     pkg->frame.size = len + 4;
0378     pkg->frame.sof = type;
0379     pkg->frame.eof = type;
0380     cpu_to_be32_array(pkg->buffer, data, len / 4);
0381     *(__be32 *) (pkg->buffer + len) = tb_crc(pkg->buffer, len);
0382 
0383     res = tb_ring_tx(ctl->tx, &pkg->frame);
0384     if (res) /* ring is stopped */
0385         tb_ctl_pkg_free(pkg);
0386     return res;
0387 }
0388 
0389 /*
0390  * tb_ctl_handle_event() - acknowledge a plug event, invoke ctl->callback
0391  */
0392 static bool tb_ctl_handle_event(struct tb_ctl *ctl, enum tb_cfg_pkg_type type,
0393                 struct ctl_pkg *pkg, size_t size)
0394 {
0395     return ctl->callback(ctl->callback_data, type, pkg->buffer, size);
0396 }
0397 
0398 static void tb_ctl_rx_submit(struct ctl_pkg *pkg)
0399 {
0400     tb_ring_rx(pkg->ctl->rx, &pkg->frame); /*
0401                          * We ignore failures during stop.
0402                          * All rx packets are referenced
0403                          * from ctl->rx_packets, so we do
0404                          * not loose them.
0405                          */
0406 }
0407 
0408 static int tb_async_error(const struct ctl_pkg *pkg)
0409 {
0410     const struct cfg_error_pkg *error = pkg->buffer;
0411 
0412     if (pkg->frame.eof != TB_CFG_PKG_ERROR)
0413         return false;
0414 
0415     switch (error->error) {
0416     case TB_CFG_ERROR_LINK_ERROR:
0417     case TB_CFG_ERROR_HEC_ERROR_DETECTED:
0418     case TB_CFG_ERROR_FLOW_CONTROL_ERROR:
0419         return true;
0420 
0421     default:
0422         return false;
0423     }
0424 }
0425 
0426 static void tb_ctl_rx_callback(struct tb_ring *ring, struct ring_frame *frame,
0427                    bool canceled)
0428 {
0429     struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
0430     struct tb_cfg_request *req;
0431     __be32 crc32;
0432 
0433     if (canceled)
0434         return; /*
0435              * ring is stopped, packet is referenced from
0436              * ctl->rx_packets.
0437              */
0438 
0439     if (frame->size < 4 || frame->size % 4 != 0) {
0440         tb_ctl_err(pkg->ctl, "RX: invalid size %#x, dropping packet\n",
0441                frame->size);
0442         goto rx;
0443     }
0444 
0445     frame->size -= 4; /* remove checksum */
0446     crc32 = tb_crc(pkg->buffer, frame->size);
0447     be32_to_cpu_array(pkg->buffer, pkg->buffer, frame->size / 4);
0448 
0449     switch (frame->eof) {
0450     case TB_CFG_PKG_READ:
0451     case TB_CFG_PKG_WRITE:
0452     case TB_CFG_PKG_ERROR:
0453     case TB_CFG_PKG_OVERRIDE:
0454     case TB_CFG_PKG_RESET:
0455         if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
0456             tb_ctl_err(pkg->ctl,
0457                    "RX: checksum mismatch, dropping packet\n");
0458             goto rx;
0459         }
0460         if (tb_async_error(pkg)) {
0461             tb_ctl_handle_event(pkg->ctl, frame->eof,
0462                         pkg, frame->size);
0463             goto rx;
0464         }
0465         break;
0466 
0467     case TB_CFG_PKG_EVENT:
0468     case TB_CFG_PKG_XDOMAIN_RESP:
0469     case TB_CFG_PKG_XDOMAIN_REQ:
0470         if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
0471             tb_ctl_err(pkg->ctl,
0472                    "RX: checksum mismatch, dropping packet\n");
0473             goto rx;
0474         }
0475         fallthrough;
0476     case TB_CFG_PKG_ICM_EVENT:
0477         if (tb_ctl_handle_event(pkg->ctl, frame->eof, pkg, frame->size))
0478             goto rx;
0479         break;
0480 
0481     default:
0482         break;
0483     }
0484 
0485     /*
0486      * The received packet will be processed only if there is an
0487      * active request and that the packet is what is expected. This
0488      * prevents packets such as replies coming after timeout has
0489      * triggered from messing with the active requests.
0490      */
0491     req = tb_cfg_request_find(pkg->ctl, pkg);
0492     if (req) {
0493         if (req->copy(req, pkg))
0494             schedule_work(&req->work);
0495         tb_cfg_request_put(req);
0496     }
0497 
0498 rx:
0499     tb_ctl_rx_submit(pkg);
0500 }
0501 
0502 static void tb_cfg_request_work(struct work_struct *work)
0503 {
0504     struct tb_cfg_request *req = container_of(work, typeof(*req), work);
0505 
0506     if (!test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
0507         req->callback(req->callback_data);
0508 
0509     tb_cfg_request_dequeue(req);
0510     tb_cfg_request_put(req);
0511 }
0512 
0513 /**
0514  * tb_cfg_request() - Start control request not waiting for it to complete
0515  * @ctl: Control channel to use
0516  * @req: Request to start
0517  * @callback: Callback called when the request is completed
0518  * @callback_data: Data to be passed to @callback
0519  *
0520  * This queues @req on the given control channel without waiting for it
0521  * to complete. When the request completes @callback is called.
0522  */
0523 int tb_cfg_request(struct tb_ctl *ctl, struct tb_cfg_request *req,
0524            void (*callback)(void *), void *callback_data)
0525 {
0526     int ret;
0527 
0528     req->flags = 0;
0529     req->callback = callback;
0530     req->callback_data = callback_data;
0531     INIT_WORK(&req->work, tb_cfg_request_work);
0532     INIT_LIST_HEAD(&req->list);
0533 
0534     tb_cfg_request_get(req);
0535     ret = tb_cfg_request_enqueue(ctl, req);
0536     if (ret)
0537         goto err_put;
0538 
0539     ret = tb_ctl_tx(ctl, req->request, req->request_size,
0540             req->request_type);
0541     if (ret)
0542         goto err_dequeue;
0543 
0544     if (!req->response)
0545         schedule_work(&req->work);
0546 
0547     return 0;
0548 
0549 err_dequeue:
0550     tb_cfg_request_dequeue(req);
0551 err_put:
0552     tb_cfg_request_put(req);
0553 
0554     return ret;
0555 }
0556 
0557 /**
0558  * tb_cfg_request_cancel() - Cancel a control request
0559  * @req: Request to cancel
0560  * @err: Error to assign to the request
0561  *
0562  * This function can be used to cancel ongoing request. It will wait
0563  * until the request is not active anymore.
0564  */
0565 void tb_cfg_request_cancel(struct tb_cfg_request *req, int err)
0566 {
0567     set_bit(TB_CFG_REQUEST_CANCELED, &req->flags);
0568     schedule_work(&req->work);
0569     wait_event(tb_cfg_request_cancel_queue, !tb_cfg_request_is_active(req));
0570     req->result.err = err;
0571 }
0572 
0573 static void tb_cfg_request_complete(void *data)
0574 {
0575     complete(data);
0576 }
0577 
0578 /**
0579  * tb_cfg_request_sync() - Start control request and wait until it completes
0580  * @ctl: Control channel to use
0581  * @req: Request to start
0582  * @timeout_msec: Timeout how long to wait @req to complete
0583  *
0584  * Starts a control request and waits until it completes. If timeout
0585  * triggers the request is canceled before function returns. Note the
0586  * caller needs to make sure only one message for given switch is active
0587  * at a time.
0588  */
0589 struct tb_cfg_result tb_cfg_request_sync(struct tb_ctl *ctl,
0590                      struct tb_cfg_request *req,
0591                      int timeout_msec)
0592 {
0593     unsigned long timeout = msecs_to_jiffies(timeout_msec);
0594     struct tb_cfg_result res = { 0 };
0595     DECLARE_COMPLETION_ONSTACK(done);
0596     int ret;
0597 
0598     ret = tb_cfg_request(ctl, req, tb_cfg_request_complete, &done);
0599     if (ret) {
0600         res.err = ret;
0601         return res;
0602     }
0603 
0604     if (!wait_for_completion_timeout(&done, timeout))
0605         tb_cfg_request_cancel(req, -ETIMEDOUT);
0606 
0607     flush_work(&req->work);
0608 
0609     return req->result;
0610 }
0611 
0612 /* public interface, alloc/start/stop/free */
0613 
0614 /**
0615  * tb_ctl_alloc() - allocate a control channel
0616  * @nhi: Pointer to NHI
0617  * @timeout_msec: Default timeout used with non-raw control messages
0618  * @cb: Callback called for plug events
0619  * @cb_data: Data passed to @cb
0620  *
0621  * cb will be invoked once for every hot plug event.
0622  *
0623  * Return: Returns a pointer on success or NULL on failure.
0624  */
0625 struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, int timeout_msec, event_cb cb,
0626                 void *cb_data)
0627 {
0628     int i;
0629     struct tb_ctl *ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
0630     if (!ctl)
0631         return NULL;
0632     ctl->nhi = nhi;
0633     ctl->timeout_msec = timeout_msec;
0634     ctl->callback = cb;
0635     ctl->callback_data = cb_data;
0636 
0637     mutex_init(&ctl->request_queue_lock);
0638     INIT_LIST_HEAD(&ctl->request_queue);
0639     ctl->frame_pool = dma_pool_create("thunderbolt_ctl", &nhi->pdev->dev,
0640                      TB_FRAME_SIZE, 4, 0);
0641     if (!ctl->frame_pool)
0642         goto err;
0643 
0644     ctl->tx = tb_ring_alloc_tx(nhi, 0, 10, RING_FLAG_NO_SUSPEND);
0645     if (!ctl->tx)
0646         goto err;
0647 
0648     ctl->rx = tb_ring_alloc_rx(nhi, 0, 10, RING_FLAG_NO_SUSPEND, 0, 0xffff,
0649                    0xffff, NULL, NULL);
0650     if (!ctl->rx)
0651         goto err;
0652 
0653     for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++) {
0654         ctl->rx_packets[i] = tb_ctl_pkg_alloc(ctl);
0655         if (!ctl->rx_packets[i])
0656             goto err;
0657         ctl->rx_packets[i]->frame.callback = tb_ctl_rx_callback;
0658     }
0659 
0660     tb_ctl_dbg(ctl, "control channel created\n");
0661     return ctl;
0662 err:
0663     tb_ctl_free(ctl);
0664     return NULL;
0665 }
0666 
0667 /**
0668  * tb_ctl_free() - free a control channel
0669  * @ctl: Control channel to free
0670  *
0671  * Must be called after tb_ctl_stop.
0672  *
0673  * Must NOT be called from ctl->callback.
0674  */
0675 void tb_ctl_free(struct tb_ctl *ctl)
0676 {
0677     int i;
0678 
0679     if (!ctl)
0680         return;
0681 
0682     if (ctl->rx)
0683         tb_ring_free(ctl->rx);
0684     if (ctl->tx)
0685         tb_ring_free(ctl->tx);
0686 
0687     /* free RX packets */
0688     for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
0689         tb_ctl_pkg_free(ctl->rx_packets[i]);
0690 
0691 
0692     dma_pool_destroy(ctl->frame_pool);
0693     kfree(ctl);
0694 }
0695 
0696 /**
0697  * tb_ctl_start() - start/resume the control channel
0698  * @ctl: Control channel to start
0699  */
0700 void tb_ctl_start(struct tb_ctl *ctl)
0701 {
0702     int i;
0703     tb_ctl_dbg(ctl, "control channel starting...\n");
0704     tb_ring_start(ctl->tx); /* is used to ack hotplug packets, start first */
0705     tb_ring_start(ctl->rx);
0706     for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
0707         tb_ctl_rx_submit(ctl->rx_packets[i]);
0708 
0709     ctl->running = true;
0710 }
0711 
0712 /**
0713  * tb_ctl_stop() - pause the control channel
0714  * @ctl: Control channel to stop
0715  *
0716  * All invocations of ctl->callback will have finished after this method
0717  * returns.
0718  *
0719  * Must NOT be called from ctl->callback.
0720  */
0721 void tb_ctl_stop(struct tb_ctl *ctl)
0722 {
0723     mutex_lock(&ctl->request_queue_lock);
0724     ctl->running = false;
0725     mutex_unlock(&ctl->request_queue_lock);
0726 
0727     tb_ring_stop(ctl->rx);
0728     tb_ring_stop(ctl->tx);
0729 
0730     if (!list_empty(&ctl->request_queue))
0731         tb_ctl_WARN(ctl, "dangling request in request_queue\n");
0732     INIT_LIST_HEAD(&ctl->request_queue);
0733     tb_ctl_dbg(ctl, "control channel stopped\n");
0734 }
0735 
0736 /* public interface, commands */
0737 
0738 /**
0739  * tb_cfg_ack_plug() - Ack hot plug/unplug event
0740  * @ctl: Control channel to use
0741  * @route: Router that originated the event
0742  * @port: Port where the hot plug/unplug happened
0743  * @unplug: Ack hot plug or unplug
0744  *
0745  * Call this as response for hot plug/unplug event to ack it.
0746  * Returns %0 on success or an error code on failure.
0747  */
0748 int tb_cfg_ack_plug(struct tb_ctl *ctl, u64 route, u32 port, bool unplug)
0749 {
0750     struct cfg_error_pkg pkg = {
0751         .header = tb_cfg_make_header(route),
0752         .port = port,
0753         .error = TB_CFG_ERROR_ACK_PLUG_EVENT,
0754         .pg = unplug ? TB_CFG_ERROR_PG_HOT_UNPLUG
0755                  : TB_CFG_ERROR_PG_HOT_PLUG,
0756     };
0757     tb_ctl_dbg(ctl, "acking hot %splug event on %llx:%x\n",
0758            unplug ? "un" : "", route, port);
0759     return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_ERROR);
0760 }
0761 
0762 static bool tb_cfg_match(const struct tb_cfg_request *req,
0763              const struct ctl_pkg *pkg)
0764 {
0765     u64 route = tb_cfg_get_route(pkg->buffer) & ~BIT_ULL(63);
0766 
0767     if (pkg->frame.eof == TB_CFG_PKG_ERROR)
0768         return true;
0769 
0770     if (pkg->frame.eof != req->response_type)
0771         return false;
0772     if (route != tb_cfg_get_route(req->request))
0773         return false;
0774     if (pkg->frame.size != req->response_size)
0775         return false;
0776 
0777     if (pkg->frame.eof == TB_CFG_PKG_READ ||
0778         pkg->frame.eof == TB_CFG_PKG_WRITE) {
0779         const struct cfg_read_pkg *req_hdr = req->request;
0780         const struct cfg_read_pkg *res_hdr = pkg->buffer;
0781 
0782         if (req_hdr->addr.seq != res_hdr->addr.seq)
0783             return false;
0784     }
0785 
0786     return true;
0787 }
0788 
0789 static bool tb_cfg_copy(struct tb_cfg_request *req, const struct ctl_pkg *pkg)
0790 {
0791     struct tb_cfg_result res;
0792 
0793     /* Now make sure it is in expected format */
0794     res = parse_header(pkg, req->response_size, req->response_type,
0795                tb_cfg_get_route(req->request));
0796     if (!res.err)
0797         memcpy(req->response, pkg->buffer, req->response_size);
0798 
0799     req->result = res;
0800 
0801     /* Always complete when first response is received */
0802     return true;
0803 }
0804 
0805 /**
0806  * tb_cfg_reset() - send a reset packet and wait for a response
0807  * @ctl: Control channel pointer
0808  * @route: Router string for the router to send reset
0809  *
0810  * If the switch at route is incorrectly configured then we will not receive a
0811  * reply (even though the switch will reset). The caller should check for
0812  * -ETIMEDOUT and attempt to reconfigure the switch.
0813  */
0814 struct tb_cfg_result tb_cfg_reset(struct tb_ctl *ctl, u64 route)
0815 {
0816     struct cfg_reset_pkg request = { .header = tb_cfg_make_header(route) };
0817     struct tb_cfg_result res = { 0 };
0818     struct tb_cfg_header reply;
0819     struct tb_cfg_request *req;
0820 
0821     req = tb_cfg_request_alloc();
0822     if (!req) {
0823         res.err = -ENOMEM;
0824         return res;
0825     }
0826 
0827     req->match = tb_cfg_match;
0828     req->copy = tb_cfg_copy;
0829     req->request = &request;
0830     req->request_size = sizeof(request);
0831     req->request_type = TB_CFG_PKG_RESET;
0832     req->response = &reply;
0833     req->response_size = sizeof(reply);
0834     req->response_type = TB_CFG_PKG_RESET;
0835 
0836     res = tb_cfg_request_sync(ctl, req, ctl->timeout_msec);
0837 
0838     tb_cfg_request_put(req);
0839 
0840     return res;
0841 }
0842 
0843 /**
0844  * tb_cfg_read_raw() - read from config space into buffer
0845  * @ctl: Pointer to the control channel
0846  * @buffer: Buffer where the data is read
0847  * @route: Route string of the router
0848  * @port: Port number when reading from %TB_CFG_PORT, %0 otherwise
0849  * @space: Config space selector
0850  * @offset: Dword word offset of the register to start reading
0851  * @length: Number of dwords to read
0852  * @timeout_msec: Timeout in ms how long to wait for the response
0853  *
0854  * Reads from router config space without translating the possible error.
0855  */
0856 struct tb_cfg_result tb_cfg_read_raw(struct tb_ctl *ctl, void *buffer,
0857         u64 route, u32 port, enum tb_cfg_space space,
0858         u32 offset, u32 length, int timeout_msec)
0859 {
0860     struct tb_cfg_result res = { 0 };
0861     struct cfg_read_pkg request = {
0862         .header = tb_cfg_make_header(route),
0863         .addr = {
0864             .port = port,
0865             .space = space,
0866             .offset = offset,
0867             .length = length,
0868         },
0869     };
0870     struct cfg_write_pkg reply;
0871     int retries = 0;
0872 
0873     while (retries < TB_CTL_RETRIES) {
0874         struct tb_cfg_request *req;
0875 
0876         req = tb_cfg_request_alloc();
0877         if (!req) {
0878             res.err = -ENOMEM;
0879             return res;
0880         }
0881 
0882         request.addr.seq = retries++;
0883 
0884         req->match = tb_cfg_match;
0885         req->copy = tb_cfg_copy;
0886         req->request = &request;
0887         req->request_size = sizeof(request);
0888         req->request_type = TB_CFG_PKG_READ;
0889         req->response = &reply;
0890         req->response_size = 12 + 4 * length;
0891         req->response_type = TB_CFG_PKG_READ;
0892 
0893         res = tb_cfg_request_sync(ctl, req, timeout_msec);
0894 
0895         tb_cfg_request_put(req);
0896 
0897         if (res.err != -ETIMEDOUT)
0898             break;
0899 
0900         /* Wait a bit (arbitrary time) until we send a retry */
0901         usleep_range(10, 100);
0902     }
0903 
0904     if (res.err)
0905         return res;
0906 
0907     res.response_port = reply.addr.port;
0908     res.err = check_config_address(reply.addr, space, offset, length);
0909     if (!res.err)
0910         memcpy(buffer, &reply.data, 4 * length);
0911     return res;
0912 }
0913 
0914 /**
0915  * tb_cfg_write_raw() - write from buffer into config space
0916  * @ctl: Pointer to the control channel
0917  * @buffer: Data to write
0918  * @route: Route string of the router
0919  * @port: Port number when writing to %TB_CFG_PORT, %0 otherwise
0920  * @space: Config space selector
0921  * @offset: Dword word offset of the register to start writing
0922  * @length: Number of dwords to write
0923  * @timeout_msec: Timeout in ms how long to wait for the response
0924  *
0925  * Writes to router config space without translating the possible error.
0926  */
0927 struct tb_cfg_result tb_cfg_write_raw(struct tb_ctl *ctl, const void *buffer,
0928         u64 route, u32 port, enum tb_cfg_space space,
0929         u32 offset, u32 length, int timeout_msec)
0930 {
0931     struct tb_cfg_result res = { 0 };
0932     struct cfg_write_pkg request = {
0933         .header = tb_cfg_make_header(route),
0934         .addr = {
0935             .port = port,
0936             .space = space,
0937             .offset = offset,
0938             .length = length,
0939         },
0940     };
0941     struct cfg_read_pkg reply;
0942     int retries = 0;
0943 
0944     memcpy(&request.data, buffer, length * 4);
0945 
0946     while (retries < TB_CTL_RETRIES) {
0947         struct tb_cfg_request *req;
0948 
0949         req = tb_cfg_request_alloc();
0950         if (!req) {
0951             res.err = -ENOMEM;
0952             return res;
0953         }
0954 
0955         request.addr.seq = retries++;
0956 
0957         req->match = tb_cfg_match;
0958         req->copy = tb_cfg_copy;
0959         req->request = &request;
0960         req->request_size = 12 + 4 * length;
0961         req->request_type = TB_CFG_PKG_WRITE;
0962         req->response = &reply;
0963         req->response_size = sizeof(reply);
0964         req->response_type = TB_CFG_PKG_WRITE;
0965 
0966         res = tb_cfg_request_sync(ctl, req, timeout_msec);
0967 
0968         tb_cfg_request_put(req);
0969 
0970         if (res.err != -ETIMEDOUT)
0971             break;
0972 
0973         /* Wait a bit (arbitrary time) until we send a retry */
0974         usleep_range(10, 100);
0975     }
0976 
0977     if (res.err)
0978         return res;
0979 
0980     res.response_port = reply.addr.port;
0981     res.err = check_config_address(reply.addr, space, offset, length);
0982     return res;
0983 }
0984 
0985 static int tb_cfg_get_error(struct tb_ctl *ctl, enum tb_cfg_space space,
0986                 const struct tb_cfg_result *res)
0987 {
0988     /*
0989      * For unimplemented ports access to port config space may return
0990      * TB_CFG_ERROR_INVALID_CONFIG_SPACE (alternatively their type is
0991      * set to TB_TYPE_INACTIVE). In the former case return -ENODEV so
0992      * that the caller can mark the port as disabled.
0993      */
0994     if (space == TB_CFG_PORT &&
0995         res->tb_error == TB_CFG_ERROR_INVALID_CONFIG_SPACE)
0996         return -ENODEV;
0997 
0998     tb_cfg_print_error(ctl, res);
0999 
1000     if (res->tb_error == TB_CFG_ERROR_LOCK)
1001         return -EACCES;
1002     else if (res->tb_error == TB_CFG_ERROR_PORT_NOT_CONNECTED)
1003         return -ENOTCONN;
1004 
1005     return -EIO;
1006 }
1007 
1008 int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
1009         enum tb_cfg_space space, u32 offset, u32 length)
1010 {
1011     struct tb_cfg_result res = tb_cfg_read_raw(ctl, buffer, route, port,
1012             space, offset, length, ctl->timeout_msec);
1013     switch (res.err) {
1014     case 0:
1015         /* Success */
1016         break;
1017 
1018     case 1:
1019         /* Thunderbolt error, tb_error holds the actual number */
1020         return tb_cfg_get_error(ctl, space, &res);
1021 
1022     case -ETIMEDOUT:
1023         tb_ctl_warn(ctl, "%llx: timeout reading config space %u from %#x\n",
1024                 route, space, offset);
1025         break;
1026 
1027     default:
1028         WARN(1, "tb_cfg_read: %d\n", res.err);
1029         break;
1030     }
1031     return res.err;
1032 }
1033 
1034 int tb_cfg_write(struct tb_ctl *ctl, const void *buffer, u64 route, u32 port,
1035          enum tb_cfg_space space, u32 offset, u32 length)
1036 {
1037     struct tb_cfg_result res = tb_cfg_write_raw(ctl, buffer, route, port,
1038             space, offset, length, ctl->timeout_msec);
1039     switch (res.err) {
1040     case 0:
1041         /* Success */
1042         break;
1043 
1044     case 1:
1045         /* Thunderbolt error, tb_error holds the actual number */
1046         return tb_cfg_get_error(ctl, space, &res);
1047 
1048     case -ETIMEDOUT:
1049         tb_ctl_warn(ctl, "%llx: timeout writing config space %u to %#x\n",
1050                 route, space, offset);
1051         break;
1052 
1053     default:
1054         WARN(1, "tb_cfg_write: %d\n", res.err);
1055         break;
1056     }
1057     return res.err;
1058 }
1059 
1060 /**
1061  * tb_cfg_get_upstream_port() - get upstream port number of switch at route
1062  * @ctl: Pointer to the control channel
1063  * @route: Route string of the router
1064  *
1065  * Reads the first dword from the switches TB_CFG_SWITCH config area and
1066  * returns the port number from which the reply originated.
1067  *
1068  * Return: Returns the upstream port number on success or an error code on
1069  * failure.
1070  */
1071 int tb_cfg_get_upstream_port(struct tb_ctl *ctl, u64 route)
1072 {
1073     u32 dummy;
1074     struct tb_cfg_result res = tb_cfg_read_raw(ctl, &dummy, route, 0,
1075                            TB_CFG_SWITCH, 0, 1,
1076                            ctl->timeout_msec);
1077     if (res.err == 1)
1078         return -EIO;
1079     if (res.err)
1080         return res.err;
1081     return res.response_port;
1082 }
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