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) 2019-2024 Linaro Ltd.
   5  */
   6
   7 #include <linux/interrupt.h>
   8 #include <linux/notifier.h>
   9 #include <linux/panic_notifier.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/pm_runtime.h>
  12 #include <linux/types.h>
  13
  14 #include <linux/soc/qcom/smem_state.h>
  15
  16 #include "ipa.h"
  17 #include "ipa_smp2p.h"
  18 #include "ipa_uc.h"
  19
  20 /**
  21  * DOC: IPA SMP2P communication with the modem
  22  *
  23  * SMP2P is a primitive communication mechanism available between the AP and
  24  * the modem.  The IPA driver uses this for two purposes:  to enable the modem
  25  * to state that the GSI hardware is ready to use; and to communicate the
  26  * state of IPA power in the event of a crash.
  27  *
  28  * GSI needs to have early initialization completed before it can be used.
  29  * This initialization is done either by Trust Zone or by the modem.  In the
  30  * latter case, the modem uses an SMP2P interrupt to tell the AP IPA driver
  31  * when the GSI is ready to use.
  32  *
  33  * The modem is also able to inquire about the current state of IPA
  34  * power by trigging another SMP2P interrupt to the AP.  We communicate
  35  * whether power is enabled using two SMP2P state bits--one to indicate
  36  * the power state (on or off), and a second to indicate the power state
  37  * bit is valid.  The modem will poll the valid bit until it is set, and
  38  * at that time records whether the AP has IPA power enabled.
  39  *
  40  * Finally, if the AP kernel panics, we update the SMP2P state bits even if
  41  * we never receive an interrupt from the modem requesting this.
  42  */
  43
  44 /**
  45  * struct ipa_smp2p - IPA SMP2P information
  46  * @ipa:                IPA pointer
  47  * @valid_state:        SMEM state indicating enabled state is valid
  48  * @enabled_state:      SMEM state to indicate power is enabled
  49  * @valid_bit:          Valid bit in 32-bit SMEM state mask
  50  * @enabled_bit:        Enabled bit in 32-bit SMEM state mask
  51  * @enabled_bit:        Enabled bit in 32-bit SMEM state mask
  52  * @clock_query_irq:    IPA interrupt triggered by modem for power query
  53  * @setup_ready_irq:    IPA interrupt triggered by modem to signal GSI ready
  54  * @power_on:           Whether IPA power is on
  55  * @notified:           Whether modem has been notified of power state
  56  * @setup_disabled:     Whether setup ready interrupt handler is disabled
  57  * @mutex:              Mutex protecting ready-interrupt/shutdown interlock
  58  * @panic_notifier:     Panic notifier structure
  59 */
  60 struct ipa_smp2p {
  61         struct ipa *ipa;
  62         struct qcom_smem_state *valid_state;
  63         struct qcom_smem_state *enabled_state;
  64         u32 valid_bit;
  65         u32 enabled_bit;
  66         u32 clock_query_irq;
  67         u32 setup_ready_irq;
  68         bool power_on;
  69         bool notified;
  70         bool setup_disabled;
  71         struct mutex mutex;
  72         struct notifier_block panic_notifier;
  73 };
  74
  75 /**
  76  * ipa_smp2p_notify() - use SMP2P to tell modem about IPA power state
  77  * @smp2p:      SMP2P information
  78  *
  79  * This is called either when the modem has requested it (by triggering
  80  * the modem power query IPA interrupt) or whenever the AP is shutting down
  81  * (via a panic notifier).  It sets the two SMP2P state bits--one saying
  82  * whether the IPA power is on, and the other indicating the first bit
  83  * is valid.
  84  */
  85 static void ipa_smp2p_notify(struct ipa_smp2p *smp2p)
  86 {
  87         u32 value;
  88         u32 mask;
  89
  90         if (smp2p->notified)
  91                 return;
  92
  93         smp2p->power_on = pm_runtime_get_if_active(smp2p->ipa->dev) > 0;
  94
  95         /* Signal whether the IPA power is enabled */
  96         mask = BIT(smp2p->enabled_bit);
  97         value = smp2p->power_on ? mask : 0;
  98         qcom_smem_state_update_bits(smp2p->enabled_state, mask, value);
  99
 100         /* Now indicate that the enabled flag is valid */
 101         mask = BIT(smp2p->valid_bit);
 102         value = mask;
 103         qcom_smem_state_update_bits(smp2p->valid_state, mask, value);
 104
 105         smp2p->notified = true;
 106 }
 107
 108 /* Threaded IRQ handler for modem "ipa-clock-query" SMP2P interrupt */
 109 static irqreturn_t ipa_smp2p_modem_clk_query_isr(int irq, void *dev_id)
 110 {
 111         struct ipa_smp2p *smp2p = dev_id;
 112
 113         ipa_smp2p_notify(smp2p);
 114
 115         return IRQ_HANDLED;
 116 }
 117
 118 static int ipa_smp2p_panic_notifier(struct notifier_block *nb,
 119                                     unsigned long action, void *data)
 120 {
 121         struct ipa_smp2p *smp2p;
 122
 123         smp2p = container_of(nb, struct ipa_smp2p, panic_notifier);
 124
 125         ipa_smp2p_notify(smp2p);
 126
 127         if (smp2p->power_on)
 128                 ipa_uc_panic_notifier(smp2p->ipa);
 129
 130         return NOTIFY_DONE;
 131 }
 132
 133 static int ipa_smp2p_panic_notifier_register(struct ipa_smp2p *smp2p)
 134 {
 135         /* IPA panic handler needs to run before modem shuts down */
 136         smp2p->panic_notifier.notifier_call = ipa_smp2p_panic_notifier;
 137         smp2p->panic_notifier.priority = INT_MAX;       /* Do it early */
 138
 139         return atomic_notifier_chain_register(&panic_notifier_list,
 140                                               &smp2p->panic_notifier);
 141 }
 142
 143 static void ipa_smp2p_panic_notifier_unregister(struct ipa_smp2p *smp2p)
 144 {
 145         atomic_notifier_chain_unregister(&panic_notifier_list,
 146                                          &smp2p->panic_notifier);
 147 }
 148
 149 /* Threaded IRQ handler for modem "ipa-setup-ready" SMP2P interrupt */
 150 static irqreturn_t ipa_smp2p_modem_setup_ready_isr(int irq, void *dev_id)
 151 {
 152         struct ipa_smp2p *smp2p = dev_id;
 153         struct ipa *ipa = smp2p->ipa;
 154         struct device *dev;
 155         int ret;
 156
 157         /* Ignore any (spurious) interrupts received after the first */
 158         if (ipa->setup_complete)
 159                 return IRQ_HANDLED;
 160
 161         /* Power needs to be active for setup */
 162         dev = ipa->dev;
 163         ret = pm_runtime_get_sync(dev);
 164         if (ret < 0) {
 165                 dev_err(dev, "error %d getting power for setup\n", ret);
 166                 goto out_power_put;
 167         }
 168
 169         /* An error here won't cause driver shutdown, so warn if one occurs */
 170         ret = ipa_setup(ipa);
 171         WARN(ret != 0, "error %d from ipa_setup()\n", ret);
 172
 173 out_power_put:
 174         pm_runtime_mark_last_busy(dev);
 175         (void)pm_runtime_put_autosuspend(dev);
 176
 177         return IRQ_HANDLED;
 178 }
 179
 180 /* Initialize SMP2P interrupts */
 181 static int ipa_smp2p_irq_init(struct ipa_smp2p *smp2p,
 182                               struct platform_device *pdev,
 183                               const char *name, irq_handler_t handler)
 184 {
 185         struct device *dev = &pdev->dev;
 186         unsigned int irq;
 187         int ret;
 188
 189         ret = platform_get_irq_byname(pdev, name);
 190         if (ret <= 0)
 191                 return ret ? : -EINVAL;
 192         irq = ret;
 193
 194         ret = request_threaded_irq(irq, NULL, handler, 0, name, smp2p);
 195         if (ret) {
 196                 dev_err(dev, "error %d requesting \"%s\" IRQ\n", ret, name);
 197                 return ret;
 198         }
 199
 200         return irq;
 201 }
 202
 203 static void ipa_smp2p_irq_exit(struct ipa_smp2p *smp2p, u32 irq)
 204 {
 205         free_irq(irq, smp2p);
 206 }
 207
 208 /* Drop the power reference if it was taken in ipa_smp2p_notify() */
 209 static void ipa_smp2p_power_release(struct ipa *ipa)
 210 {
 211         struct device *dev = ipa->dev;
 212
 213         if (!ipa->smp2p->power_on)
 214                 return;
 215
 216         pm_runtime_mark_last_busy(dev);
 217         (void)pm_runtime_put_autosuspend(dev);
 218         ipa->smp2p->power_on = false;
 219 }
 220
 221 /* Initialize the IPA SMP2P subsystem */
 222 int
 223 ipa_smp2p_init(struct ipa *ipa, struct platform_device *pdev, bool modem_init)
 224 {
 225         struct qcom_smem_state *enabled_state;
 226         struct device *dev = &pdev->dev;
 227         struct qcom_smem_state *valid_state;
 228         struct ipa_smp2p *smp2p;
 229         u32 enabled_bit;
 230         u32 valid_bit;
 231         int ret;
 232
 233         valid_state = qcom_smem_state_get(dev, "ipa-clock-enabled-valid",
 234                                           &valid_bit);
 235         if (IS_ERR(valid_state))
 236                 return PTR_ERR(valid_state);
 237         if (valid_bit >= 32)            /* BITS_PER_U32 */
 238                 return -EINVAL;
 239
 240         enabled_state = qcom_smem_state_get(dev, "ipa-clock-enabled",
 241                                             &enabled_bit);
 242         if (IS_ERR(enabled_state))
 243                 return PTR_ERR(enabled_state);
 244         if (enabled_bit >= 32)          /* BITS_PER_U32 */
 245                 return -EINVAL;
 246
 247         smp2p = kzalloc(sizeof(*smp2p), GFP_KERNEL);
 248         if (!smp2p)
 249                 return -ENOMEM;
 250
 251         smp2p->ipa = ipa;
 252
 253         /* These fields are needed by the power query interrupt
 254          * handler, so initialize them now.
 255          */
 256         mutex_init(&smp2p->mutex);
 257         smp2p->valid_state = valid_state;
 258         smp2p->valid_bit = valid_bit;
 259         smp2p->enabled_state = enabled_state;
 260         smp2p->enabled_bit = enabled_bit;
 261
 262         /* We have enough information saved to handle notifications */
 263         ipa->smp2p = smp2p;
 264
 265         ret = ipa_smp2p_irq_init(smp2p, pdev, "ipa-clock-query",
 266                                  ipa_smp2p_modem_clk_query_isr);
 267         if (ret < 0)
 268                 goto err_null_smp2p;
 269         smp2p->clock_query_irq = ret;
 270
 271         ret = ipa_smp2p_panic_notifier_register(smp2p);
 272         if (ret)
 273                 goto err_irq_exit;
 274
 275         if (modem_init) {
 276                 /* Result will be non-zero (negative for error) */
 277                 ret = ipa_smp2p_irq_init(smp2p, pdev, "ipa-setup-ready",
 278                                          ipa_smp2p_modem_setup_ready_isr);
 279                 if (ret < 0)
 280                         goto err_notifier_unregister;
 281                 smp2p->setup_ready_irq = ret;
 282         }
 283
 284         return 0;
 285
 286 err_notifier_unregister:
 287         ipa_smp2p_panic_notifier_unregister(smp2p);
 288 err_irq_exit:
 289         ipa_smp2p_irq_exit(smp2p, smp2p->clock_query_irq);
 290 err_null_smp2p:
 291         ipa->smp2p = NULL;
 292         mutex_destroy(&smp2p->mutex);
 293         kfree(smp2p);
 294
 295         return ret;
 296 }
 297
 298 void ipa_smp2p_exit(struct ipa *ipa)
 299 {
 300         struct ipa_smp2p *smp2p = ipa->smp2p;
 301
 302         if (smp2p->setup_ready_irq)
 303                 ipa_smp2p_irq_exit(smp2p, smp2p->setup_ready_irq);
 304         ipa_smp2p_panic_notifier_unregister(smp2p);
 305         ipa_smp2p_irq_exit(smp2p, smp2p->clock_query_irq);
 306         /* We won't get notified any more; drop power reference (if any) */
 307         ipa_smp2p_power_release(ipa);
 308         ipa->smp2p = NULL;
 309         mutex_destroy(&smp2p->mutex);
 310         kfree(smp2p);
 311 }
 312
 313 void ipa_smp2p_irq_disable_setup(struct ipa *ipa)
 314 {
 315         struct ipa_smp2p *smp2p = ipa->smp2p;
 316
 317         if (!smp2p->setup_ready_irq)
 318                 return;
 319
 320         mutex_lock(&smp2p->mutex);
 321
 322         if (!smp2p->setup_disabled) {
 323                 disable_irq(smp2p->setup_ready_irq);
 324                 smp2p->setup_disabled = true;
 325         }
 326
 327         mutex_unlock(&smp2p->mutex);
 328 }
 329
 330 /* Reset state tracking whether we have notified the modem */
 331 void ipa_smp2p_notify_reset(struct ipa *ipa)
 332 {
 333         struct ipa_smp2p *smp2p = ipa->smp2p;
 334         u32 mask;
 335
 336         if (!smp2p->notified)
 337                 return;
 338
 339         ipa_smp2p_power_release(ipa);
 340
 341         /* Reset the power enabled valid flag */
 342         mask = BIT(smp2p->valid_bit);
 343         qcom_smem_state_update_bits(smp2p->valid_state, mask, 0);
 344
 345         /* Mark the power disabled for good measure... */
 346         mask = BIT(smp2p->enabled_bit);
 347         qcom_smem_state_update_bits(smp2p->enabled_state, mask, 0);
 348
 349         smp2p->notified = false;
 350 }