1 // SPDX-License-Identifier: GPL-2.0 2 3 /* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved. 4 * Copyright (C) 2019-2022 Linaro Ltd. 5 */ 6 7 #include <linux/types.h> 8 #include <linux/platform_device.h> 9 #include <linux/interrupt.h> 10 #include <linux/notifier.h> 11 #include <linux/panic_notifier.h> 12 #include <linux/pm_runtime.h> 13 #include <linux/soc/qcom/smem.h> 14 #include <linux/soc/qcom/smem_state.h> 15 16 #include "ipa_smp2p.h" 17 #include "ipa.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 } 351