drivers/mailbox/stm32-ipcc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) STMicroelectronics 2018 - All Rights Reserved
   4  * Authors: Ludovic Barre <ludovic.barre@st.com> for STMicroelectronics.
   5  *          Fabien Dessenne <fabien.dessenne@st.com> for STMicroelectronics.
   6  */
   7
   8 #include <linux/bitfield.h>
   9 #include <linux/clk.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/io.h>
  12 #include <linux/mailbox_controller.h>
  13 #include <linux/module.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/pm_wakeirq.h>
  16
  17 #define IPCC_XCR                0x000
  18 #define XCR_RXOIE               BIT(0)
  19 #define XCR_TXOIE               BIT(16)
  20
  21 #define IPCC_XMR                0x004
  22 #define IPCC_XSCR               0x008
  23 #define IPCC_XTOYSR             0x00c
  24
  25 #define IPCC_PROC_OFFST         0x010
  26
  27 #define IPCC_HWCFGR             0x3f0
  28 #define IPCFGR_CHAN_MASK        GENMASK(7, 0)
  29
  30 #define IPCC_VER                0x3f4
  31 #define VER_MINREV_MASK         GENMASK(3, 0)
  32 #define VER_MAJREV_MASK         GENMASK(7, 4)
  33
  34 #define RX_BIT_MASK             GENMASK(15, 0)
  35 #define RX_BIT_CHAN(chan)       BIT(chan)
  36 #define TX_BIT_SHIFT            16
  37 #define TX_BIT_MASK             GENMASK(31, 16)
  38 #define TX_BIT_CHAN(chan)       BIT(TX_BIT_SHIFT + (chan))
  39
  40 #define STM32_MAX_PROCS         2
  41
  42 enum {
  43         IPCC_IRQ_RX,
  44         IPCC_IRQ_TX,
  45         IPCC_IRQ_NUM,
  46 };
  47
  48 struct stm32_ipcc {
  49         struct mbox_controller controller;
  50         void __iomem *reg_base;
  51         void __iomem *reg_proc;
  52         struct clk *clk;
  53         spinlock_t lock; /* protect access to IPCC registers */
  54         int irqs[IPCC_IRQ_NUM];
  55         int wkp;
  56         u32 proc_id;
  57         u32 n_chans;
  58         u32 xcr;
  59         u32 xmr;
  60 };
  61
  62 static inline void stm32_ipcc_set_bits(spinlock_t *lock, void __iomem *reg,
  63                                        u32 mask)
  64 {
  65         unsigned long flags;
  66
  67         spin_lock_irqsave(lock, flags);
  68         writel_relaxed(readl_relaxed(reg) | mask, reg);
  69         spin_unlock_irqrestore(lock, flags);
  70 }
  71
  72 static inline void stm32_ipcc_clr_bits(spinlock_t *lock, void __iomem *reg,
  73                                        u32 mask)
  74 {
  75         unsigned long flags;
  76
  77         spin_lock_irqsave(lock, flags);
  78         writel_relaxed(readl_relaxed(reg) & ~mask, reg);
  79         spin_unlock_irqrestore(lock, flags);
  80 }
  81
  82 static irqreturn_t stm32_ipcc_rx_irq(int irq, void *data)
  83 {
  84         struct stm32_ipcc *ipcc = data;
  85         struct device *dev = ipcc->controller.dev;
  86         u32 status, mr, tosr, chan;
  87         irqreturn_t ret = IRQ_NONE;
  88         int proc_offset;
  89
  90         /* read 'channel occupied' status from other proc */
  91         proc_offset = ipcc->proc_id ? -IPCC_PROC_OFFST : IPCC_PROC_OFFST;
  92         tosr = readl_relaxed(ipcc->reg_proc + proc_offset + IPCC_XTOYSR);
  93         mr = readl_relaxed(ipcc->reg_proc + IPCC_XMR);
  94
  95         /* search for unmasked 'channel occupied' */
  96         status = tosr & FIELD_GET(RX_BIT_MASK, ~mr);
  97
  98         for (chan = 0; chan < ipcc->n_chans; chan++) {
  99                 if (!(status & (1 << chan)))
 100                         continue;
 101
 102                 dev_dbg(dev, "%s: chan:%d rx\n", __func__, chan);
 103
 104                 mbox_chan_received_data(&ipcc->controller.chans[chan], NULL);
 105
 106                 stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XSCR,
 107                                     RX_BIT_CHAN(chan));
 108
 109                 ret = IRQ_HANDLED;
 110         }
 111
 112         return ret;
 113 }
 114
 115 static irqreturn_t stm32_ipcc_tx_irq(int irq, void *data)
 116 {
 117         struct stm32_ipcc *ipcc = data;
 118         struct device *dev = ipcc->controller.dev;
 119         u32 status, mr, tosr, chan;
 120         irqreturn_t ret = IRQ_NONE;
 121
 122         tosr = readl_relaxed(ipcc->reg_proc + IPCC_XTOYSR);
 123         mr = readl_relaxed(ipcc->reg_proc + IPCC_XMR);
 124
 125         /* search for unmasked 'channel free' */
 126         status = ~tosr & FIELD_GET(TX_BIT_MASK, ~mr);
 127
 128         for (chan = 0; chan < ipcc->n_chans ; chan++) {
 129                 if (!(status & (1 << chan)))
 130                         continue;
 131
 132                 dev_dbg(dev, "%s: chan:%d tx\n", __func__, chan);
 133
 134                 /* mask 'tx channel free' interrupt */
 135                 stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
 136                                     TX_BIT_CHAN(chan));
 137
 138                 mbox_chan_txdone(&ipcc->controller.chans[chan], 0);
 139
 140                 ret = IRQ_HANDLED;
 141         }
 142
 143         return ret;
 144 }
 145
 146 static int stm32_ipcc_send_data(struct mbox_chan *link, void *data)
 147 {
 148         unsigned int chan = (unsigned int)link->con_priv;
 149         struct stm32_ipcc *ipcc = container_of(link->mbox, struct stm32_ipcc,
 150                                                controller);
 151
 152         dev_dbg(ipcc->controller.dev, "%s: chan:%d\n", __func__, chan);
 153
 154         /* set channel n occupied */
 155         stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XSCR,
 156                             TX_BIT_CHAN(chan));
 157
 158         /* unmask 'tx channel free' interrupt */
 159         stm32_ipcc_clr_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
 160                             TX_BIT_CHAN(chan));
 161
 162         return 0;
 163 }
 164
 165 static int stm32_ipcc_startup(struct mbox_chan *link)
 166 {
 167         unsigned int chan = (unsigned int)link->con_priv;
 168         struct stm32_ipcc *ipcc = container_of(link->mbox, struct stm32_ipcc,
 169                                                controller);
 170         int ret;
 171
 172         ret = clk_prepare_enable(ipcc->clk);
 173         if (ret) {
 174                 dev_err(ipcc->controller.dev, "can not enable the clock\n");
 175                 return ret;
 176         }
 177
 178         /* unmask 'rx channel occupied' interrupt */
 179         stm32_ipcc_clr_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
 180                             RX_BIT_CHAN(chan));
 181
 182         return 0;
 183 }
 184
 185 static void stm32_ipcc_shutdown(struct mbox_chan *link)
 186 {
 187         unsigned int chan = (unsigned int)link->con_priv;
 188         struct stm32_ipcc *ipcc = container_of(link->mbox, struct stm32_ipcc,
 189                                                controller);
 190
 191         /* mask rx/tx interrupt */
 192         stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
 193                             RX_BIT_CHAN(chan) | TX_BIT_CHAN(chan));
 194
 195         clk_disable_unprepare(ipcc->clk);
 196 }
 197
 198 static const struct mbox_chan_ops stm32_ipcc_ops = {
 199         .send_data      = stm32_ipcc_send_data,
 200         .startup        = stm32_ipcc_startup,
 201         .shutdown       = stm32_ipcc_shutdown,
 202 };
 203
 204 static int stm32_ipcc_probe(struct platform_device *pdev)
 205 {
 206         struct device *dev = &pdev->dev;
 207         struct device_node *np = dev->of_node;
 208         struct stm32_ipcc *ipcc;
 209         struct resource *res;
 210         unsigned int i;
 211         int ret;
 212         u32 ip_ver;
 213         static const char * const irq_name[] = {"rx", "tx"};
 214         irq_handler_t irq_thread[] = {stm32_ipcc_rx_irq, stm32_ipcc_tx_irq};
 215
 216         if (!np) {
 217                 dev_err(dev, "No DT found\n");
 218                 return -ENODEV;
 219         }
 220
 221         ipcc = devm_kzalloc(dev, sizeof(*ipcc), GFP_KERNEL);
 222         if (!ipcc)
 223                 return -ENOMEM;
 224
 225         spin_lock_init(&ipcc->lock);
 226
 227         /* proc_id */
 228         if (of_property_read_u32(np, "st,proc-id", &ipcc->proc_id)) {
 229                 dev_err(dev, "Missing st,proc-id\n");
 230                 return -ENODEV;
 231         }
 232
 233         if (ipcc->proc_id >= STM32_MAX_PROCS) {
 234                 dev_err(dev, "Invalid proc_id (%d)\n", ipcc->proc_id);
 235                 return -EINVAL;
 236         }
 237
 238         /* regs */
 239         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 240         ipcc->reg_base = devm_ioremap_resource(dev, res);
 241         if (IS_ERR(ipcc->reg_base))
 242                 return PTR_ERR(ipcc->reg_base);
 243
 244         ipcc->reg_proc = ipcc->reg_base + ipcc->proc_id * IPCC_PROC_OFFST;
 245
 246         /* clock */
 247         ipcc->clk = devm_clk_get(dev, NULL);
 248         if (IS_ERR(ipcc->clk))
 249                 return PTR_ERR(ipcc->clk);
 250
 251         ret = clk_prepare_enable(ipcc->clk);
 252         if (ret) {
 253                 dev_err(dev, "can not enable the clock\n");
 254                 return ret;
 255         }
 256
 257         /* irq */
 258         for (i = 0; i < IPCC_IRQ_NUM; i++) {
 259                 ipcc->irqs[i] = platform_get_irq_byname(pdev, irq_name[i]);
 260                 if (ipcc->irqs[i] < 0) {
 261                         if (ipcc->irqs[i] != -EPROBE_DEFER)
 262                                 dev_err(dev, "no IRQ specified %s\n",
 263                                         irq_name[i]);
 264                         ret = ipcc->irqs[i];
 265                         goto err_clk;
 266                 }
 267
 268                 ret = devm_request_threaded_irq(dev, ipcc->irqs[i], NULL,
 269                                                 irq_thread[i], IRQF_ONESHOT,
 270                                                 dev_name(dev), ipcc);
 271                 if (ret) {
 272                         dev_err(dev, "failed to request irq %d (%d)\n", i, ret);
 273                         goto err_clk;
 274                 }
 275         }
 276
 277         /* mask and enable rx/tx irq */
 278         stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
 279                             RX_BIT_MASK | TX_BIT_MASK);
 280         stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XCR,
 281                             XCR_RXOIE | XCR_TXOIE);
 282
 283         /* wakeup */
 284         if (of_property_read_bool(np, "wakeup-source")) {
 285                 ipcc->wkp = platform_get_irq_byname(pdev, "wakeup");
 286                 if (ipcc->wkp < 0) {
 287                         if (ipcc->wkp != -EPROBE_DEFER)
 288                                 dev_err(dev, "could not get wakeup IRQ\n");
 289                         ret = ipcc->wkp;
 290                         goto err_clk;
 291                 }
 292
 293                 device_init_wakeup(dev, true);
 294                 ret = dev_pm_set_dedicated_wake_irq(dev, ipcc->wkp);
 295                 if (ret) {
 296                         dev_err(dev, "Failed to set wake up irq\n");
 297                         goto err_init_wkp;
 298                 }
 299         } else {
 300                 device_init_wakeup(dev, false);
 301         }
 302
 303         /* mailbox controller */
 304         ipcc->n_chans = readl_relaxed(ipcc->reg_base + IPCC_HWCFGR);
 305         ipcc->n_chans &= IPCFGR_CHAN_MASK;
 306
 307         ipcc->controller.dev = dev;
 308         ipcc->controller.txdone_irq = true;
 309         ipcc->controller.ops = &stm32_ipcc_ops;
 310         ipcc->controller.num_chans = ipcc->n_chans;
 311         ipcc->controller.chans = devm_kcalloc(dev, ipcc->controller.num_chans,
 312                                               sizeof(*ipcc->controller.chans),
 313                                               GFP_KERNEL);
 314         if (!ipcc->controller.chans) {
 315                 ret = -ENOMEM;
 316                 goto err_irq_wkp;
 317         }
 318
 319         for (i = 0; i < ipcc->controller.num_chans; i++)
 320                 ipcc->controller.chans[i].con_priv = (void *)i;
 321
 322         ret = mbox_controller_register(&ipcc->controller);
 323         if (ret)
 324                 goto err_irq_wkp;
 325
 326         platform_set_drvdata(pdev, ipcc);
 327
 328         ip_ver = readl_relaxed(ipcc->reg_base + IPCC_VER);
 329
 330         dev_info(dev, "ipcc rev:%ld.%ld enabled, %d chans, proc %d\n",
 331                  FIELD_GET(VER_MAJREV_MASK, ip_ver),
 332                  FIELD_GET(VER_MINREV_MASK, ip_ver),
 333                  ipcc->controller.num_chans, ipcc->proc_id);
 334
 335         clk_disable_unprepare(ipcc->clk);
 336         return 0;
 337
 338 err_irq_wkp:
 339         if (ipcc->wkp)
 340                 dev_pm_clear_wake_irq(dev);
 341 err_init_wkp:
 342         device_init_wakeup(dev, false);
 343 err_clk:
 344         clk_disable_unprepare(ipcc->clk);
 345         return ret;
 346 }
 347
 348 static int stm32_ipcc_remove(struct platform_device *pdev)
 349 {
 350         struct stm32_ipcc *ipcc = platform_get_drvdata(pdev);
 351
 352         mbox_controller_unregister(&ipcc->controller);
 353
 354         if (ipcc->wkp)
 355                 dev_pm_clear_wake_irq(&pdev->dev);
 356
 357         device_init_wakeup(&pdev->dev, false);
 358
 359         return 0;
 360 }
 361
 362 #ifdef CONFIG_PM_SLEEP
 363 static void stm32_ipcc_set_irq_wake(struct device *dev, bool enable)
 364 {
 365         struct stm32_ipcc *ipcc = dev_get_drvdata(dev);
 366         unsigned int i;
 367
 368         if (device_may_wakeup(dev))
 369                 for (i = 0; i < IPCC_IRQ_NUM; i++)
 370                         irq_set_irq_wake(ipcc->irqs[i], enable);
 371 }
 372
 373 static int stm32_ipcc_suspend(struct device *dev)
 374 {
 375         struct stm32_ipcc *ipcc = dev_get_drvdata(dev);
 376
 377         ipcc->xmr = readl_relaxed(ipcc->reg_proc + IPCC_XMR);
 378         ipcc->xcr = readl_relaxed(ipcc->reg_proc + IPCC_XCR);
 379
 380         stm32_ipcc_set_irq_wake(dev, true);
 381
 382         return 0;
 383 }
 384
 385 static int stm32_ipcc_resume(struct device *dev)
 386 {
 387         struct stm32_ipcc *ipcc = dev_get_drvdata(dev);
 388
 389         stm32_ipcc_set_irq_wake(dev, false);
 390
 391         writel_relaxed(ipcc->xmr, ipcc->reg_proc + IPCC_XMR);
 392         writel_relaxed(ipcc->xcr, ipcc->reg_proc + IPCC_XCR);
 393
 394         return 0;
 395 }
 396 #endif
 397
 398 static SIMPLE_DEV_PM_OPS(stm32_ipcc_pm_ops,
 399                          stm32_ipcc_suspend, stm32_ipcc_resume);
 400
 401 static const struct of_device_id stm32_ipcc_of_match[] = {
 402         { .compatible = "st,stm32mp1-ipcc" },
 403         {},
 404 };
 405 MODULE_DEVICE_TABLE(of, stm32_ipcc_of_match);
 406
 407 static struct platform_driver stm32_ipcc_driver = {
 408         .driver = {
 409                 .name = "stm32-ipcc",
 410                 .pm = &stm32_ipcc_pm_ops,
 411                 .of_match_table = stm32_ipcc_of_match,
 412         },
 413         .probe          = stm32_ipcc_probe,
 414         .remove         = stm32_ipcc_remove,
 415 };
 416
 417 module_platform_driver(stm32_ipcc_driver);
 418
 419 MODULE_AUTHOR("Ludovic Barre <ludovic.barre@st.com>");
 420 MODULE_AUTHOR("Fabien Dessenne <fabien.dessenne@st.com>");
 421 MODULE_DESCRIPTION("STM32 IPCC driver");
 422 MODULE_LICENSE("GPL v2");