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