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/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 the IPA clock 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 the IPA 34 * clock by trigging another SMP2P interrupt to the AP. We communicate 35 * whether the clock is enabled using two SMP2P state bits--one to 36 * indicate the clock state (on or off), and a second to indicate the 37 * clock state bit is valid. The modem will poll the valid bit until it 38 * is set, and at that time records whether the AP has the IPA clock 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 clock 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 clock query 53 * @setup_ready_irq: IPA interrupt triggered by modem to signal GSI ready 54 * @clock_on: Whether IPA clock is on 55 * @notified: Whether modem has been notified of clock state 56 * @disabled: Whether setup ready interrupt handling 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 clock_on; 69 bool notified; 70 bool 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 clock state 77 * @smp2p: SMP2P information 78 * 79 * This is called either when the modem has requested it (by triggering 80 * the modem clock 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 clock is running, and the other indicating the first bit 83 * is valid. 84 */ 85 static void ipa_smp2p_notify(struct ipa_smp2p *smp2p) 86 { 87 struct device *dev; 88 u32 value; 89 u32 mask; 90 91 if (smp2p->notified) 92 return; 93 94 dev = &smp2p->ipa->pdev->dev; 95 smp2p->clock_on = pm_runtime_get_if_active(dev, true) > 0; 96 97 /* Signal whether the clock is enabled */ 98 mask = BIT(smp2p->enabled_bit); 99 value = smp2p->clock_on ? mask : 0; 100 qcom_smem_state_update_bits(smp2p->enabled_state, mask, value); 101 102 /* Now indicate that the enabled flag is valid */ 103 mask = BIT(smp2p->valid_bit); 104 value = mask; 105 qcom_smem_state_update_bits(smp2p->valid_state, mask, value); 106 107 smp2p->notified = true; 108 } 109 110 /* Threaded IRQ handler for modem "ipa-clock-query" SMP2P interrupt */ 111 static irqreturn_t ipa_smp2p_modem_clk_query_isr(int irq, void *dev_id) 112 { 113 struct ipa_smp2p *smp2p = dev_id; 114 115 ipa_smp2p_notify(smp2p); 116 117 return IRQ_HANDLED; 118 } 119 120 static int ipa_smp2p_panic_notifier(struct notifier_block *nb, 121 unsigned long action, void *data) 122 { 123 struct ipa_smp2p *smp2p; 124 125 smp2p = container_of(nb, struct ipa_smp2p, panic_notifier); 126 127 ipa_smp2p_notify(smp2p); 128 129 if (smp2p->clock_on) 130 ipa_uc_panic_notifier(smp2p->ipa); 131 132 return NOTIFY_DONE; 133 } 134 135 static int ipa_smp2p_panic_notifier_register(struct ipa_smp2p *smp2p) 136 { 137 /* IPA panic handler needs to run before modem shuts down */ 138 smp2p->panic_notifier.notifier_call = ipa_smp2p_panic_notifier; 139 smp2p->panic_notifier.priority = INT_MAX; /* Do it early */ 140 141 return atomic_notifier_chain_register(&panic_notifier_list, 142 &smp2p->panic_notifier); 143 } 144 145 static void ipa_smp2p_panic_notifier_unregister(struct ipa_smp2p *smp2p) 146 { 147 atomic_notifier_chain_unregister(&panic_notifier_list, 148 &smp2p->panic_notifier); 149 } 150 151 /* Threaded IRQ handler for modem "ipa-setup-ready" SMP2P interrupt */ 152 static irqreturn_t ipa_smp2p_modem_setup_ready_isr(int irq, void *dev_id) 153 { 154 struct ipa_smp2p *smp2p = dev_id; 155 struct device *dev; 156 int ret; 157 158 mutex_lock(&smp2p->mutex); 159 160 if (smp2p->disabled) 161 goto out_mutex_unlock; 162 smp2p->disabled = true; /* If any others arrive, ignore them */ 163 164 /* Power needs to be active for setup */ 165 dev = &smp2p->ipa->pdev->dev; 166 ret = pm_runtime_get_sync(dev); 167 if (ret < 0) { 168 dev_err(dev, "error %d getting power for setup\n", ret); 169 goto out_power_put; 170 } 171 172 /* An error here won't cause driver shutdown, so warn if one occurs */ 173 ret = ipa_setup(smp2p->ipa); 174 WARN(ret != 0, "error %d from ipa_setup()\n", ret); 175 176 out_power_put: 177 (void)pm_runtime_put(dev); 178 out_mutex_unlock: 179 mutex_unlock(&smp2p->mutex); 180 181 return IRQ_HANDLED; 182 } 183 184 /* Initialize SMP2P interrupts */ 185 static int ipa_smp2p_irq_init(struct ipa_smp2p *smp2p, const char *name, 186 irq_handler_t handler) 187 { 188 struct device *dev = &smp2p->ipa->pdev->dev; 189 unsigned int irq; 190 int ret; 191 192 ret = platform_get_irq_byname(smp2p->ipa->pdev, name); 193 if (ret <= 0) 194 return ret ? : -EINVAL; 195 irq = ret; 196 197 ret = request_threaded_irq(irq, NULL, handler, 0, name, smp2p); 198 if (ret) { 199 dev_err(dev, "error %d requesting \"%s\" IRQ\n", ret, name); 200 return ret; 201 } 202 203 return irq; 204 } 205 206 static void ipa_smp2p_irq_exit(struct ipa_smp2p *smp2p, u32 irq) 207 { 208 free_irq(irq, smp2p); 209 } 210 211 /* Drop the clock reference if it was taken in ipa_smp2p_notify() */ 212 static void ipa_smp2p_clock_release(struct ipa *ipa) 213 { 214 if (!ipa->smp2p->clock_on) 215 return; 216 217 (void)pm_runtime_put(&ipa->pdev->dev); 218 ipa->smp2p->clock_on = false; 219 } 220 221 /* Initialize the IPA SMP2P subsystem */ 222 int ipa_smp2p_init(struct ipa *ipa, bool modem_init) 223 { 224 struct qcom_smem_state *enabled_state; 225 struct device *dev = &ipa->pdev->dev; 226 struct qcom_smem_state *valid_state; 227 struct ipa_smp2p *smp2p; 228 u32 enabled_bit; 229 u32 valid_bit; 230 int ret; 231 232 valid_state = qcom_smem_state_get(dev, "ipa-clock-enabled-valid", 233 &valid_bit); 234 if (IS_ERR(valid_state)) 235 return PTR_ERR(valid_state); 236 if (valid_bit >= 32) /* BITS_PER_U32 */ 237 return -EINVAL; 238 239 enabled_state = qcom_smem_state_get(dev, "ipa-clock-enabled", 240 &enabled_bit); 241 if (IS_ERR(enabled_state)) 242 return PTR_ERR(enabled_state); 243 if (enabled_bit >= 32) /* BITS_PER_U32 */ 244 return -EINVAL; 245 246 smp2p = kzalloc(sizeof(*smp2p), GFP_KERNEL); 247 if (!smp2p) 248 return -ENOMEM; 249 250 smp2p->ipa = ipa; 251 252 /* These fields are needed by the clock query interrupt 253 * handler, so initialize them now. 254 */ 255 mutex_init(&smp2p->mutex); 256 smp2p->valid_state = valid_state; 257 smp2p->valid_bit = valid_bit; 258 smp2p->enabled_state = enabled_state; 259 smp2p->enabled_bit = enabled_bit; 260 261 /* We have enough information saved to handle notifications */ 262 ipa->smp2p = smp2p; 263 264 ret = ipa_smp2p_irq_init(smp2p, "ipa-clock-query", 265 ipa_smp2p_modem_clk_query_isr); 266 if (ret < 0) 267 goto err_null_smp2p; 268 smp2p->clock_query_irq = ret; 269 270 ret = ipa_smp2p_panic_notifier_register(smp2p); 271 if (ret) 272 goto err_irq_exit; 273 274 if (modem_init) { 275 /* Result will be non-zero (negative for error) */ 276 ret = ipa_smp2p_irq_init(smp2p, "ipa-setup-ready", 277 ipa_smp2p_modem_setup_ready_isr); 278 if (ret < 0) 279 goto err_notifier_unregister; 280 smp2p->setup_ready_irq = ret; 281 } 282 283 return 0; 284 285 err_notifier_unregister: 286 ipa_smp2p_panic_notifier_unregister(smp2p); 287 err_irq_exit: 288 ipa_smp2p_irq_exit(smp2p, smp2p->clock_query_irq); 289 err_null_smp2p: 290 ipa->smp2p = NULL; 291 mutex_destroy(&smp2p->mutex); 292 kfree(smp2p); 293 294 return ret; 295 } 296 297 void ipa_smp2p_exit(struct ipa *ipa) 298 { 299 struct ipa_smp2p *smp2p = ipa->smp2p; 300 301 if (smp2p->setup_ready_irq) 302 ipa_smp2p_irq_exit(smp2p, smp2p->setup_ready_irq); 303 ipa_smp2p_panic_notifier_unregister(smp2p); 304 ipa_smp2p_irq_exit(smp2p, smp2p->clock_query_irq); 305 /* We won't get notified any more; drop clock reference (if any) */ 306 ipa_smp2p_clock_release(ipa); 307 ipa->smp2p = NULL; 308 mutex_destroy(&smp2p->mutex); 309 kfree(smp2p); 310 } 311 312 void ipa_smp2p_disable(struct ipa *ipa) 313 { 314 struct ipa_smp2p *smp2p = ipa->smp2p; 315 316 if (!smp2p->setup_ready_irq) 317 return; 318 319 mutex_lock(&smp2p->mutex); 320 321 smp2p->disabled = true; 322 323 mutex_unlock(&smp2p->mutex); 324 } 325 326 /* Reset state tracking whether we have notified the modem */ 327 void ipa_smp2p_notify_reset(struct ipa *ipa) 328 { 329 struct ipa_smp2p *smp2p = ipa->smp2p; 330 u32 mask; 331 332 if (!smp2p->notified) 333 return; 334 335 ipa_smp2p_clock_release(ipa); 336 337 /* Reset the clock enabled valid flag */ 338 mask = BIT(smp2p->valid_bit); 339 qcom_smem_state_update_bits(smp2p->valid_state, mask, 0); 340 341 /* Mark the clock disabled for good measure... */ 342 mask = BIT(smp2p->enabled_bit); 343 qcom_smem_state_update_bits(smp2p->enabled_state, mask, 0); 344 345 smp2p->notified = false; 346 } 347