drivers/net/ipa/ipa_smp2p.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 /* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
   4  * Copyright (C) 2019-2020 Linaro Ltd.
   5  */
   6
   7 #include <linux/types.h>
   8 #include <linux/device.h>
   9 #include <linux/interrupt.h>
  10 #include <linux/notifier.h>
  11 #include <linux/soc/qcom/smem.h>
  12 #include <linux/soc/qcom/smem_state.h>
  13
  14 #include "ipa_smp2p.h"
  15 #include "ipa.h"
  16 #include "ipa_uc.h"
  17 #include "ipa_clock.h"
  18
  19 /**
  20  * DOC: IPA SMP2P communication with the modem
  21  *
  22  * SMP2P is a primitive communication mechanism available between the AP and
  23  * the modem.  The IPA driver uses this for two purposes:  to enable the modem
  24  * to state that the GSI hardware is ready to use; and to communicate the
  25  * state of the IPA clock in the event of a crash.
  26  *
  27  * GSI needs to have early initialization completed before it can be used.
  28  * This initialization is done either by Trust Zone or by the modem.  In the
  29  * latter case, the modem uses an SMP2P interrupt to tell the AP IPA driver
  30  * when the GSI is ready to use.
  31  *
  32  * The modem is also able to inquire about the current state of the IPA
  33  * clock by trigging another SMP2P interrupt to the AP.  We communicate
  34  * whether the clock is enabled using two SMP2P state bits--one to
  35  * indicate the clock state (on or off), and a second to indicate the
  36  * clock state bit is valid.  The modem will poll the valid bit until it
  37  * is set, and at that time records whether the AP has the IPA clock enabled.
  38  *
  39  * Finally, if the AP kernel panics, we update the SMP2P state bits even if
  40  * we never receive an interrupt from the modem requesting this.
  41  */
  42
  43 /**
  44  * struct ipa_smp2p - IPA SMP2P information
  45  * @ipa:                IPA pointer
  46  * @valid_state:        SMEM state indicating enabled state is valid
  47  * @enabled_state:      SMEM state to indicate clock is enabled
  48  * @valid_bit:          Valid bit in 32-bit SMEM state mask
  49  * @enabled_bit:        Enabled bit in 32-bit SMEM state mask
  50  * @enabled_bit:        Enabled bit in 32-bit SMEM state mask
  51  * @clock_query_irq:    IPA interrupt triggered by modem for clock query
  52  * @setup_ready_irq:    IPA interrupt triggered by modem to signal GSI ready
  53  * @clock_on:           Whether IPA clock is on
  54  * @notified:           Whether modem has been notified of clock state
  55  * @disabled:           Whether setup ready interrupt handling is disabled
  56  * @mutex mutex:        Motex protecting ready interrupt/shutdown interlock
  57  * @panic_notifier:     Panic notifier structure
  58 */
  59 struct ipa_smp2p {
  60         struct ipa *ipa;
  61         struct qcom_smem_state *valid_state;
  62         struct qcom_smem_state *enabled_state;
  63         u32 valid_bit;
  64         u32 enabled_bit;
  65         u32 clock_query_irq;
  66         u32 setup_ready_irq;
  67         bool clock_on;
  68         bool notified;
  69         bool disabled;
  70         struct mutex mutex;
  71         struct notifier_block panic_notifier;
  72 };
  73
  74 /**
  75  * ipa_smp2p_notify() - use SMP2P to tell modem about IPA clock state
  76  * @smp2p:      SMP2P information
  77  *
  78  * This is called either when the modem has requested it (by triggering
  79  * the modem clock query IPA interrupt) or whenever the AP is shutting down
  80  * (via a panic notifier).  It sets the two SMP2P state bits--one saying
  81  * whether the IPA clock is running, and the other indicating the first bit
  82  * is valid.
  83  */
  84 static void ipa_smp2p_notify(struct ipa_smp2p *smp2p)
  85 {
  86         u32 value;
  87         u32 mask;
  88
  89         if (smp2p->notified)
  90                 return;
  91
  92         smp2p->clock_on = ipa_clock_get_additional(smp2p->ipa);
  93
  94         /* Signal whether the clock is enabled */
  95         mask = BIT(smp2p->enabled_bit);
  96         value = smp2p->clock_on ? mask : 0;
  97         qcom_smem_state_update_bits(smp2p->enabled_state, mask, value);
  98
  99         /* Now indicate that the enabled flag is valid */
 100         mask = BIT(smp2p->valid_bit);
 101         value = mask;
 102         qcom_smem_state_update_bits(smp2p->valid_state, mask, value);
 103
 104         smp2p->notified = true;
 105 }
 106
 107 /* Threaded IRQ handler for modem "ipa-clock-query" SMP2P interrupt */
 108 static irqreturn_t ipa_smp2p_modem_clk_query_isr(int irq, void *dev_id)
 109 {
 110         struct ipa_smp2p *smp2p = dev_id;
 111
 112         ipa_smp2p_notify(smp2p);
 113
 114         return IRQ_HANDLED;
 115 }
 116
 117 static int ipa_smp2p_panic_notifier(struct notifier_block *nb,
 118                                     unsigned long action, void *data)
 119 {
 120         struct ipa_smp2p *smp2p;
 121
 122         smp2p = container_of(nb, struct ipa_smp2p, panic_notifier);
 123
 124         ipa_smp2p_notify(smp2p);
 125
 126         if (smp2p->clock_on)
 127                 ipa_uc_panic_notifier(smp2p->ipa);
 128
 129         return NOTIFY_DONE;
 130 }
 131
 132 static int ipa_smp2p_panic_notifier_register(struct ipa_smp2p *smp2p)
 133 {
 134         /* IPA panic handler needs to run before modem shuts down */
 135         smp2p->panic_notifier.notifier_call = ipa_smp2p_panic_notifier;
 136         smp2p->panic_notifier.priority = INT_MAX;       /* Do it early */
 137
 138         return atomic_notifier_chain_register(&panic_notifier_list,
 139                                               &smp2p->panic_notifier);
 140 }
 141
 142 static void ipa_smp2p_panic_notifier_unregister(struct ipa_smp2p *smp2p)
 143 {
 144         atomic_notifier_chain_unregister(&panic_notifier_list,
 145                                          &smp2p->panic_notifier);
 146 }
 147
 148 /* Threaded IRQ handler for modem "ipa-setup-ready" SMP2P interrupt */
 149 static irqreturn_t ipa_smp2p_modem_setup_ready_isr(int irq, void *dev_id)
 150 {
 151         struct ipa_smp2p *smp2p = dev_id;
 152
 153         mutex_lock(&smp2p->mutex);
 154
 155         if (!smp2p->disabled) {
 156                 int ret;
 157
 158                 ret = ipa_setup(smp2p->ipa);
 159                 if (ret)
 160                         dev_err(&smp2p->ipa->pdev->dev,
 161                                 "error %d from ipa_setup()\n", ret);
 162                 smp2p->disabled = true;
 163         }
 164
 165         mutex_unlock(&smp2p->mutex);
 166
 167         return IRQ_HANDLED;
 168 }
 169
 170 /* Initialize SMP2P interrupts */
 171 static int ipa_smp2p_irq_init(struct ipa_smp2p *smp2p, const char *name,
 172                               irq_handler_t handler)
 173 {
 174         struct device *dev = &smp2p->ipa->pdev->dev;
 175         unsigned int irq;
 176         int ret;
 177
 178         ret = platform_get_irq_byname(smp2p->ipa->pdev, name);
 179         if (ret <= 0) {
 180                 dev_err(dev, "DT error %d getting \"%s\" IRQ property\n",
 181                         ret, name);
 182                 return ret ? : -EINVAL;
 183         }
 184         irq = ret;
 185
 186         ret = request_threaded_irq(irq, NULL, handler, 0, name, smp2p);
 187         if (ret) {
 188                 dev_err(dev, "error %d requesting \"%s\" IRQ\n", ret, name);
 189                 return ret;
 190         }
 191
 192         return irq;
 193 }
 194
 195 static void ipa_smp2p_irq_exit(struct ipa_smp2p *smp2p, u32 irq)
 196 {
 197         free_irq(irq, smp2p);
 198 }
 199
 200 /* Drop the clock reference if it was taken in ipa_smp2p_notify() */
 201 static void ipa_smp2p_clock_release(struct ipa *ipa)
 202 {
 203         if (!ipa->smp2p->clock_on)
 204                 return;
 205
 206         ipa_clock_put(ipa);
 207         ipa->smp2p->clock_on = false;
 208 }
 209
 210 /* Initialize the IPA SMP2P subsystem */
 211 int ipa_smp2p_init(struct ipa *ipa, bool modem_init)
 212 {
 213         struct qcom_smem_state *enabled_state;
 214         struct device *dev = &ipa->pdev->dev;
 215         struct qcom_smem_state *valid_state;
 216         struct ipa_smp2p *smp2p;
 217         u32 enabled_bit;
 218         u32 valid_bit;
 219         int ret;
 220
 221         valid_state = qcom_smem_state_get(dev, "ipa-clock-enabled-valid",
 222                                           &valid_bit);
 223         if (IS_ERR(valid_state))
 224                 return PTR_ERR(valid_state);
 225         if (valid_bit >= 32)            /* BITS_PER_U32 */
 226                 return -EINVAL;
 227
 228         enabled_state = qcom_smem_state_get(dev, "ipa-clock-enabled",
 229                                             &enabled_bit);
 230         if (IS_ERR(enabled_state))
 231                 return PTR_ERR(enabled_state);
 232         if (enabled_bit >= 32)          /* BITS_PER_U32 */
 233                 return -EINVAL;
 234
 235         smp2p = kzalloc(sizeof(*smp2p), GFP_KERNEL);
 236         if (!smp2p)
 237                 return -ENOMEM;
 238
 239         smp2p->ipa = ipa;
 240
 241         /* These fields are needed by the clock query interrupt
 242          * handler, so initialize them now.
 243          */
 244         mutex_init(&smp2p->mutex);
 245         smp2p->valid_state = valid_state;
 246         smp2p->valid_bit = valid_bit;
 247         smp2p->enabled_state = enabled_state;
 248         smp2p->enabled_bit = enabled_bit;
 249
 250         /* We have enough information saved to handle notifications */
 251         ipa->smp2p = smp2p;
 252
 253         ret = ipa_smp2p_irq_init(smp2p, "ipa-clock-query",
 254                                  ipa_smp2p_modem_clk_query_isr);
 255         if (ret < 0)
 256                 goto err_null_smp2p;
 257         smp2p->clock_query_irq = ret;
 258
 259         ret = ipa_smp2p_panic_notifier_register(smp2p);
 260         if (ret)
 261                 goto err_irq_exit;
 262
 263         if (modem_init) {
 264                 /* Result will be non-zero (negative for error) */
 265                 ret = ipa_smp2p_irq_init(smp2p, "ipa-setup-ready",
 266                                          ipa_smp2p_modem_setup_ready_isr);
 267                 if (ret < 0)
 268                         goto err_notifier_unregister;
 269                 smp2p->setup_ready_irq = ret;
 270         }
 271
 272         return 0;
 273
 274 err_notifier_unregister:
 275         ipa_smp2p_panic_notifier_unregister(smp2p);
 276 err_irq_exit:
 277         ipa_smp2p_irq_exit(smp2p, smp2p->clock_query_irq);
 278 err_null_smp2p:
 279         ipa->smp2p = NULL;
 280         mutex_destroy(&smp2p->mutex);
 281         kfree(smp2p);
 282
 283         return ret;
 284 }
 285
 286 void ipa_smp2p_exit(struct ipa *ipa)
 287 {
 288         struct ipa_smp2p *smp2p = ipa->smp2p;
 289
 290         if (smp2p->setup_ready_irq)
 291                 ipa_smp2p_irq_exit(smp2p, smp2p->setup_ready_irq);
 292         ipa_smp2p_panic_notifier_unregister(smp2p);
 293         ipa_smp2p_irq_exit(smp2p, smp2p->clock_query_irq);
 294         /* We won't get notified any more; drop clock reference (if any) */
 295         ipa_smp2p_clock_release(ipa);
 296         ipa->smp2p = NULL;
 297         mutex_destroy(&smp2p->mutex);
 298         kfree(smp2p);
 299 }
 300
 301 void ipa_smp2p_disable(struct ipa *ipa)
 302 {
 303         struct ipa_smp2p *smp2p = ipa->smp2p;
 304
 305         if (!smp2p->setup_ready_irq)
 306                 return;
 307
 308         mutex_lock(&smp2p->mutex);
 309
 310         smp2p->disabled = true;
 311
 312         mutex_unlock(&smp2p->mutex);
 313 }
 314
 315 /* Reset state tracking whether we have notified the modem */
 316 void ipa_smp2p_notify_reset(struct ipa *ipa)
 317 {
 318         struct ipa_smp2p *smp2p = ipa->smp2p;
 319         u32 mask;
 320
 321         if (!smp2p->notified)
 322                 return;
 323
 324         ipa_smp2p_clock_release(ipa);
 325
 326         /* Reset the clock enabled valid flag */
 327         mask = BIT(smp2p->valid_bit);
 328         qcom_smem_state_update_bits(smp2p->valid_state, mask, 0);
 329
 330         /* Mark the clock disabled for good measure... */
 331         mask = BIT(smp2p->enabled_bit);
 332         qcom_smem_state_update_bits(smp2p->enabled_state, mask, 0);
 333
 334         smp2p->notified = false;
 335 }