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/of.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/pm_wakeirq.h>
  17
  18 #define IPCC_XCR                0x000
  19 #define XCR_RXOIE               BIT(0)
  20 #define XCR_TXOIE               BIT(16)
  21
  22 #define IPCC_XMR                0x004
  23 #define IPCC_XSCR               0x008
  24 #define IPCC_XTOYSR             0x00c
  25
  26 #define IPCC_PROC_OFFST         0x010
  27
  28 #define IPCC_HWCFGR             0x3f0
  29 #define IPCFGR_CHAN_MASK        GENMASK(7, 0)
  30
  31 #define IPCC_VER                0x3f4
  32 #define VER_MINREV_MASK         GENMASK(3, 0)
  33 #define VER_MAJREV_MASK         GENMASK(7, 4)
  34
  35 #define RX_BIT_MASK             GENMASK(15, 0)
  36 #define RX_BIT_CHAN(chan)       BIT(chan)
  37 #define TX_BIT_SHIFT            16
  38 #define TX_BIT_MASK             GENMASK(31, 16)
  39 #define TX_BIT_CHAN(chan)       BIT(TX_BIT_SHIFT + (chan))
  40
  41 #define STM32_MAX_PROCS         2
  42
  43 enum {
  44         IPCC_IRQ_RX,
  45         IPCC_IRQ_TX,
  46         IPCC_IRQ_NUM,
  47 };
  48
  49 struct stm32_ipcc {
  50         struct mbox_controller controller;
  51         void __iomem *reg_base;
  52         void __iomem *reg_proc;
  53         struct clk *clk;
  54         spinlock_t lock; /* protect access to IPCC registers */
  55         int irqs[IPCC_IRQ_NUM];
  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 long chan = (unsigned long)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:%lu\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 long chan = (unsigned long)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 long chan = (unsigned long)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         unsigned long i;
 210         int ret;
 211         u32 ip_ver;
 212         static const char * const irq_name[] = {"rx", "tx"};
 213         irq_handler_t irq_thread[] = {stm32_ipcc_rx_irq, stm32_ipcc_tx_irq};
 214
 215         if (!np) {
 216                 dev_err(dev, "No DT found\n");
 217                 return -ENODEV;
 218         }
 219
 220         ipcc = devm_kzalloc(dev, sizeof(*ipcc), GFP_KERNEL);
 221         if (!ipcc)
 222                 return -ENOMEM;
 223
 224         spin_lock_init(&ipcc->lock);
 225
 226         /* proc_id */
 227         if (of_property_read_u32(np, "st,proc-id", &ipcc->proc_id)) {
 228                 dev_err(dev, "Missing st,proc-id\n");
 229                 return -ENODEV;
 230         }
 231
 232         if (ipcc->proc_id >= STM32_MAX_PROCS) {
 233                 dev_err(dev, "Invalid proc_id (%d)\n", ipcc->proc_id);
 234                 return -EINVAL;
 235         }
 236
 237         /* regs */
 238         ipcc->reg_base = devm_platform_ioremap_resource(pdev, 0);
 239         if (IS_ERR(ipcc->reg_base))
 240                 return PTR_ERR(ipcc->reg_base);
 241
 242         ipcc->reg_proc = ipcc->reg_base + ipcc->proc_id * IPCC_PROC_OFFST;
 243
 244         /* clock */
 245         ipcc->clk = devm_clk_get(dev, NULL);
 246         if (IS_ERR(ipcc->clk))
 247                 return PTR_ERR(ipcc->clk);
 248
 249         ret = clk_prepare_enable(ipcc->clk);
 250         if (ret) {
 251                 dev_err(dev, "can not enable the clock\n");
 252                 return ret;
 253         }
 254
 255         /* irq */
 256         for (i = 0; i < IPCC_IRQ_NUM; i++) {
 257                 ipcc->irqs[i] = platform_get_irq_byname(pdev, irq_name[i]);
 258                 if (ipcc->irqs[i] < 0) {
 259                         ret = ipcc->irqs[i];
 260                         goto err_clk;
 261                 }
 262
 263                 ret = devm_request_threaded_irq(dev, ipcc->irqs[i], NULL,
 264                                                 irq_thread[i], IRQF_ONESHOT,
 265                                                 dev_name(dev), ipcc);
 266                 if (ret) {
 267                         dev_err(dev, "failed to request irq %lu (%d)\n", i, ret);
 268                         goto err_clk;
 269                 }
 270         }
 271
 272         /* mask and enable rx/tx irq */
 273         stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
 274                             RX_BIT_MASK | TX_BIT_MASK);
 275         stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XCR,
 276                             XCR_RXOIE | XCR_TXOIE);
 277
 278         /* wakeup */
 279         if (of_property_read_bool(np, "wakeup-source")) {
 280                 device_set_wakeup_capable(dev, true);
 281
 282                 ret = dev_pm_set_wake_irq(dev, ipcc->irqs[IPCC_IRQ_RX]);
 283                 if (ret) {
 284                         dev_err(dev, "Failed to set wake up irq\n");
 285                         goto err_init_wkp;
 286                 }
 287         }
 288
 289         /* mailbox controller */
 290         ipcc->n_chans = readl_relaxed(ipcc->reg_base + IPCC_HWCFGR);
 291         ipcc->n_chans &= IPCFGR_CHAN_MASK;
 292
 293         ipcc->controller.dev = dev;
 294         ipcc->controller.txdone_irq = true;
 295         ipcc->controller.ops = &stm32_ipcc_ops;
 296         ipcc->controller.num_chans = ipcc->n_chans;
 297         ipcc->controller.chans = devm_kcalloc(dev, ipcc->controller.num_chans,
 298                                               sizeof(*ipcc->controller.chans),
 299                                               GFP_KERNEL);
 300         if (!ipcc->controller.chans) {
 301                 ret = -ENOMEM;
 302                 goto err_irq_wkp;
 303         }
 304
 305         for (i = 0; i < ipcc->controller.num_chans; i++)
 306                 ipcc->controller.chans[i].con_priv = (void *)i;
 307
 308         ret = devm_mbox_controller_register(dev, &ipcc->controller);
 309         if (ret)
 310                 goto err_irq_wkp;
 311
 312         platform_set_drvdata(pdev, ipcc);
 313
 314         ip_ver = readl_relaxed(ipcc->reg_base + IPCC_VER);
 315
 316         dev_info(dev, "ipcc rev:%ld.%ld enabled, %d chans, proc %d\n",
 317                  FIELD_GET(VER_MAJREV_MASK, ip_ver),
 318                  FIELD_GET(VER_MINREV_MASK, ip_ver),
 319                  ipcc->controller.num_chans, ipcc->proc_id);
 320
 321         clk_disable_unprepare(ipcc->clk);
 322         return 0;
 323
 324 err_irq_wkp:
 325         if (of_property_read_bool(np, "wakeup-source"))
 326                 dev_pm_clear_wake_irq(dev);
 327 err_init_wkp:
 328         device_set_wakeup_capable(dev, false);
 329 err_clk:
 330         clk_disable_unprepare(ipcc->clk);
 331         return ret;
 332 }
 333
 334 static void stm32_ipcc_remove(struct platform_device *pdev)
 335 {
 336         struct device *dev = &pdev->dev;
 337
 338         if (of_property_read_bool(dev->of_node, "wakeup-source"))
 339                 dev_pm_clear_wake_irq(&pdev->dev);
 340
 341         device_set_wakeup_capable(dev, false);
 342 }
 343
 344 #ifdef CONFIG_PM_SLEEP
 345 static int stm32_ipcc_suspend(struct device *dev)
 346 {
 347         struct stm32_ipcc *ipcc = dev_get_drvdata(dev);
 348
 349         ipcc->xmr = readl_relaxed(ipcc->reg_proc + IPCC_XMR);
 350         ipcc->xcr = readl_relaxed(ipcc->reg_proc + IPCC_XCR);
 351
 352         return 0;
 353 }
 354
 355 static int stm32_ipcc_resume(struct device *dev)
 356 {
 357         struct stm32_ipcc *ipcc = dev_get_drvdata(dev);
 358
 359         writel_relaxed(ipcc->xmr, ipcc->reg_proc + IPCC_XMR);
 360         writel_relaxed(ipcc->xcr, ipcc->reg_proc + IPCC_XCR);
 361
 362         return 0;
 363 }
 364 #endif
 365
 366 static SIMPLE_DEV_PM_OPS(stm32_ipcc_pm_ops,
 367                          stm32_ipcc_suspend, stm32_ipcc_resume);
 368
 369 static const struct of_device_id stm32_ipcc_of_match[] = {
 370         { .compatible = "st,stm32mp1-ipcc" },
 371         {},
 372 };
 373 MODULE_DEVICE_TABLE(of, stm32_ipcc_of_match);
 374
 375 static struct platform_driver stm32_ipcc_driver = {
 376         .driver = {
 377                 .name = "stm32-ipcc",
 378                 .pm = &stm32_ipcc_pm_ops,
 379                 .of_match_table = stm32_ipcc_of_match,
 380         },
 381         .probe          = stm32_ipcc_probe,
 382         .remove_new     = stm32_ipcc_remove,
 383 };
 384
 385 module_platform_driver(stm32_ipcc_driver);
 386
 387 MODULE_AUTHOR("Ludovic Barre <ludovic.barre@st.com>");
 388 MODULE_AUTHOR("Fabien Dessenne <fabien.dessenne@st.com>");
 389 MODULE_DESCRIPTION("STM32 IPCC driver");
 390 MODULE_LICENSE("GPL v2");