drivers/staging/wfx/bh.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Interrupt bottom half (BH).
   4  *
   5  * Copyright (c) 2017-2020, Silicon Laboratories, Inc.
   6  * Copyright (c) 2010, ST-Ericsson
   7  */
   8 #include <linux/gpio/consumer.h>
   9 #include <net/mac80211.h>
  10
  11 #include "bh.h"
  12 #include "wfx.h"
  13 #include "hwio.h"
  14 #include "traces.h"
  15 #include "hif_rx.h"
  16 #include "hif_api_cmd.h"
  17
  18 static void device_wakeup(struct wfx_dev *wdev)
  19 {
  20         int max_retry = 3;
  21
  22         if (!wdev->pdata.gpio_wakeup)
  23                 return;
  24         if (gpiod_get_value_cansleep(wdev->pdata.gpio_wakeup) > 0)
  25                 return;
  26
  27         if (wfx_api_older_than(wdev, 1, 4)) {
  28                 gpiod_set_value_cansleep(wdev->pdata.gpio_wakeup, 1);
  29                 if (!completion_done(&wdev->hif.ctrl_ready))
  30                         usleep_range(2000, 2500);
  31                 return;
  32         }
  33         for (;;) {
  34                 gpiod_set_value_cansleep(wdev->pdata.gpio_wakeup, 1);
  35                 // completion.h does not provide any function to wait
  36                 // completion without consume it (a kind of
  37                 // wait_for_completion_done_timeout()). So we have to emulate
  38                 // it.
  39                 if (wait_for_completion_timeout(&wdev->hif.ctrl_ready,
  40                                                 msecs_to_jiffies(2))) {
  41                         complete(&wdev->hif.ctrl_ready);
  42                         return;
  43                 } else if (max_retry-- > 0) {
  44                         // Older firmwares have a race in sleep/wake-up process.
  45                         // Redo the process is sufficient to unfreeze the
  46                         // chip.
  47                         dev_err(wdev->dev, "timeout while wake up chip\n");
  48                         gpiod_set_value_cansleep(wdev->pdata.gpio_wakeup, 0);
  49                         usleep_range(2000, 2500);
  50                 } else {
  51                         dev_err(wdev->dev, "max wake-up retries reached\n");
  52                         return;
  53                 }
  54         }
  55 }
  56
  57 static void device_release(struct wfx_dev *wdev)
  58 {
  59         if (!wdev->pdata.gpio_wakeup)
  60                 return;
  61
  62         gpiod_set_value_cansleep(wdev->pdata.gpio_wakeup, 0);
  63 }
  64
  65 static int rx_helper(struct wfx_dev *wdev, size_t read_len, int *is_cnf)
  66 {
  67         struct sk_buff *skb;
  68         struct hif_msg *hif;
  69         size_t alloc_len;
  70         size_t computed_len;
  71         int release_count;
  72         int piggyback = 0;
  73
  74         WARN(read_len > round_down(0xFFF, 2) * sizeof(u16),
  75              "%s: request exceed WFx capability", __func__);
  76
  77         // Add 2 to take into account piggyback size
  78         alloc_len = wdev->hwbus_ops->align_size(wdev->hwbus_priv, read_len + 2);
  79         skb = dev_alloc_skb(alloc_len);
  80         if (!skb)
  81                 return -ENOMEM;
  82
  83         if (wfx_data_read(wdev, skb->data, alloc_len))
  84                 goto err;
  85
  86         piggyback = le16_to_cpup((__le16 *)(skb->data + alloc_len - 2));
  87         _trace_piggyback(piggyback, false);
  88
  89         hif = (struct hif_msg *)skb->data;
  90         WARN(hif->encrypted & 0x3, "encryption is unsupported");
  91         if (WARN(read_len < sizeof(struct hif_msg), "corrupted read"))
  92                 goto err;
  93         computed_len = le16_to_cpu(hif->len);
  94         computed_len = round_up(computed_len, 2);
  95         if (computed_len != read_len) {
  96                 dev_err(wdev->dev, "inconsistent message length: %zu != %zu\n",
  97                         computed_len, read_len);
  98                 print_hex_dump(KERN_INFO, "hif: ", DUMP_PREFIX_OFFSET, 16, 1,
  99                                hif, read_len, true);
 100                 goto err;
 101         }
 102
 103         if (!(hif->id & HIF_ID_IS_INDICATION)) {
 104                 (*is_cnf)++;
 105                 if (hif->id == HIF_CNF_ID_MULTI_TRANSMIT)
 106                         release_count = ((struct hif_cnf_multi_transmit *)hif->body)->num_tx_confs;
 107                 else
 108                         release_count = 1;
 109                 WARN(wdev->hif.tx_buffers_used < release_count, "corrupted buffer counter");
 110                 wdev->hif.tx_buffers_used -= release_count;
 111         }
 112         _trace_hif_recv(hif, wdev->hif.tx_buffers_used);
 113
 114         if (hif->id != HIF_IND_ID_EXCEPTION && hif->id != HIF_IND_ID_ERROR) {
 115                 if (hif->seqnum != wdev->hif.rx_seqnum)
 116                         dev_warn(wdev->dev, "wrong message sequence: %d != %d\n",
 117                                  hif->seqnum, wdev->hif.rx_seqnum);
 118                 wdev->hif.rx_seqnum = (hif->seqnum + 1) % (HIF_COUNTER_MAX + 1);
 119         }
 120
 121         skb_put(skb, le16_to_cpu(hif->len));
 122         // wfx_handle_rx takes care on SKB livetime
 123         wfx_handle_rx(wdev, skb);
 124         if (!wdev->hif.tx_buffers_used)
 125                 wake_up(&wdev->hif.tx_buffers_empty);
 126
 127         return piggyback;
 128
 129 err:
 130         if (skb)
 131                 dev_kfree_skb(skb);
 132         return -EIO;
 133 }
 134
 135 static int bh_work_rx(struct wfx_dev *wdev, int max_msg, int *num_cnf)
 136 {
 137         size_t len;
 138         int i;
 139         int ctrl_reg, piggyback;
 140
 141         piggyback = 0;
 142         for (i = 0; i < max_msg; i++) {
 143                 if (piggyback & CTRL_NEXT_LEN_MASK)
 144                         ctrl_reg = piggyback;
 145                 else if (try_wait_for_completion(&wdev->hif.ctrl_ready))
 146                         ctrl_reg = atomic_xchg(&wdev->hif.ctrl_reg, 0);
 147                 else
 148                         ctrl_reg = 0;
 149                 if (!(ctrl_reg & CTRL_NEXT_LEN_MASK))
 150                         return i;
 151                 // ctrl_reg units are 16bits words
 152                 len = (ctrl_reg & CTRL_NEXT_LEN_MASK) * 2;
 153                 piggyback = rx_helper(wdev, len, num_cnf);
 154                 if (piggyback < 0)
 155                         return i;
 156                 if (!(piggyback & CTRL_WLAN_READY))
 157                         dev_err(wdev->dev, "unexpected piggyback value: ready bit not set: %04x\n",
 158                                 piggyback);
 159         }
 160         if (piggyback & CTRL_NEXT_LEN_MASK) {
 161                 ctrl_reg = atomic_xchg(&wdev->hif.ctrl_reg, piggyback);
 162                 complete(&wdev->hif.ctrl_ready);
 163                 if (ctrl_reg)
 164                         dev_err(wdev->dev, "unexpected IRQ happened: %04x/%04x\n",
 165                                 ctrl_reg, piggyback);
 166         }
 167         return i;
 168 }
 169
 170 static void tx_helper(struct wfx_dev *wdev, struct hif_msg *hif)
 171 {
 172         int ret;
 173         void *data;
 174         bool is_encrypted = false;
 175         size_t len = le16_to_cpu(hif->len);
 176
 177         WARN(len < sizeof(*hif), "try to send corrupted data");
 178
 179         hif->seqnum = wdev->hif.tx_seqnum;
 180         wdev->hif.tx_seqnum = (wdev->hif.tx_seqnum + 1) % (HIF_COUNTER_MAX + 1);
 181
 182         data = hif;
 183         WARN(len > wdev->hw_caps.size_inp_ch_buf,
 184              "%s: request exceed WFx capability: %zu > %d\n", __func__,
 185              len, wdev->hw_caps.size_inp_ch_buf);
 186         len = wdev->hwbus_ops->align_size(wdev->hwbus_priv, len);
 187         ret = wfx_data_write(wdev, data, len);
 188         if (ret)
 189                 goto end;
 190
 191         wdev->hif.tx_buffers_used++;
 192         _trace_hif_send(hif, wdev->hif.tx_buffers_used);
 193 end:
 194         if (is_encrypted)
 195                 kfree(data);
 196 }
 197
 198 static int bh_work_tx(struct wfx_dev *wdev, int max_msg)
 199 {
 200         struct hif_msg *hif;
 201         int i;
 202
 203         for (i = 0; i < max_msg; i++) {
 204                 hif = NULL;
 205                 if (wdev->hif.tx_buffers_used < wdev->hw_caps.num_inp_ch_bufs) {
 206                         if (try_wait_for_completion(&wdev->hif_cmd.ready)) {
 207                                 WARN(!mutex_is_locked(&wdev->hif_cmd.lock), "data locking error");
 208                                 hif = wdev->hif_cmd.buf_send;
 209                         } else {
 210                                 hif = wfx_tx_queues_get(wdev);
 211                         }
 212                 }
 213                 if (!hif)
 214                         return i;
 215                 tx_helper(wdev, hif);
 216         }
 217         return i;
 218 }
 219
 220 /* In SDIO mode, it is necessary to make an access to a register to acknowledge
 221  * last received message. It could be possible to restrict this acknowledge to
 222  * SDIO mode and only if last operation was rx.
 223  */
 224 static void ack_sdio_data(struct wfx_dev *wdev)
 225 {
 226         u32 cfg_reg;
 227
 228         config_reg_read(wdev, &cfg_reg);
 229         if (cfg_reg & 0xFF) {
 230                 dev_warn(wdev->dev, "chip reports errors: %02x\n",
 231                          cfg_reg & 0xFF);
 232                 config_reg_write_bits(wdev, 0xFF, 0x00);
 233         }
 234 }
 235
 236 static void bh_work(struct work_struct *work)
 237 {
 238         struct wfx_dev *wdev = container_of(work, struct wfx_dev, hif.bh);
 239         int stats_req = 0, stats_cnf = 0, stats_ind = 0;
 240         bool release_chip = false, last_op_is_rx = false;
 241         int num_tx, num_rx;
 242
 243         device_wakeup(wdev);
 244         do {
 245                 num_tx = bh_work_tx(wdev, 32);
 246                 stats_req += num_tx;
 247                 if (num_tx)
 248                         last_op_is_rx = false;
 249                 num_rx = bh_work_rx(wdev, 32, &stats_cnf);
 250                 stats_ind += num_rx;
 251                 if (num_rx)
 252                         last_op_is_rx = true;
 253         } while (num_rx || num_tx);
 254         stats_ind -= stats_cnf;
 255
 256         if (last_op_is_rx)
 257                 ack_sdio_data(wdev);
 258         if (!wdev->hif.tx_buffers_used && !work_pending(work)) {
 259                 device_release(wdev);
 260                 release_chip = true;
 261         }
 262         _trace_bh_stats(stats_ind, stats_req, stats_cnf,
 263                         wdev->hif.tx_buffers_used, release_chip);
 264 }
 265
 266 /*
 267  * An IRQ from chip did occur
 268  */
 269 void wfx_bh_request_rx(struct wfx_dev *wdev)
 270 {
 271         u32 cur, prev;
 272
 273         control_reg_read(wdev, &cur);
 274         prev = atomic_xchg(&wdev->hif.ctrl_reg, cur);
 275         complete(&wdev->hif.ctrl_ready);
 276         queue_work(system_highpri_wq, &wdev->hif.bh);
 277
 278         if (!(cur & CTRL_NEXT_LEN_MASK))
 279                 dev_err(wdev->dev, "unexpected control register value: length field is 0: %04x\n",
 280                         cur);
 281         if (prev != 0)
 282                 dev_err(wdev->dev, "received IRQ but previous data was not (yet) read: %04x/%04x\n",
 283                         prev, cur);
 284 }
 285
 286 /*
 287  * Driver want to send data
 288  */
 289 void wfx_bh_request_tx(struct wfx_dev *wdev)
 290 {
 291         queue_work(system_highpri_wq, &wdev->hif.bh);
 292 }
 293
 294 /*
 295  * If IRQ is not available, this function allow to manually poll the control
 296  * register and simulate an IRQ ahen an event happened.
 297  *
 298  * Note that the device has a bug: If an IRQ raise while host read control
 299  * register, the IRQ is lost. So, use this function carefully (only duing
 300  * device initialisation).
 301  */
 302 void wfx_bh_poll_irq(struct wfx_dev *wdev)
 303 {
 304         ktime_t now, start;
 305         u32 reg;
 306
 307         WARN(!wdev->poll_irq, "unexpected IRQ polling can mask IRQ");
 308         start = ktime_get();
 309         for (;;) {
 310                 control_reg_read(wdev, &reg);
 311                 now = ktime_get();
 312                 if (reg & 0xFFF)
 313                         break;
 314                 if (ktime_after(now, ktime_add_ms(start, 1000))) {
 315                         dev_err(wdev->dev, "time out while polling control register\n");
 316                         return;
 317                 }
 318                 udelay(200);
 319         }
 320         wfx_bh_request_rx(wdev);
 321 }
 322
 323 void wfx_bh_register(struct wfx_dev *wdev)
 324 {
 325         INIT_WORK(&wdev->hif.bh, bh_work);
 326         init_completion(&wdev->hif.ctrl_ready);
 327         init_waitqueue_head(&wdev->hif.tx_buffers_empty);
 328 }
 329
 330 void wfx_bh_unregister(struct wfx_dev *wdev)
 331 {
 332         flush_work(&wdev->hif.bh);
 333 }