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         u32 proc_id;
  56         u32 n_chans;
  57         u32 xcr;
  58         u32 xmr;
  59 };
  60
  61 static inline void stm32_ipcc_set_bits(spinlock_t *lock, void __iomem *reg,
  62                                        u32 mask)
  63 {
  64         unsigned long flags;
  65
  66         spin_lock_irqsave(lock, flags);
  67         writel_relaxed(readl_relaxed(reg) | mask, reg);
  68         spin_unlock_irqrestore(lock, flags);
  69 }
  70
  71 static inline void stm32_ipcc_clr_bits(spinlock_t *lock, void __iomem *reg,
  72                                        u32 mask)
  73 {
  74         unsigned long flags;
  75
  76         spin_lock_irqsave(lock, flags);
  77         writel_relaxed(readl_relaxed(reg) & ~mask, reg);
  78         spin_unlock_irqrestore(lock, flags);
  79 }
  80
  81 static irqreturn_t stm32_ipcc_rx_irq(int irq, void *data)
  82 {
  83         struct stm32_ipcc *ipcc = data;
  84         struct device *dev = ipcc->controller.dev;
  85         u32 status, mr, tosr, chan;
  86         irqreturn_t ret = IRQ_NONE;
  87         int proc_offset;
  88
  89         /* read 'channel occupied' status from other proc */
  90         proc_offset = ipcc->proc_id ? -IPCC_PROC_OFFST : IPCC_PROC_OFFST;
  91         tosr = readl_relaxed(ipcc->reg_proc + proc_offset + IPCC_XTOYSR);
  92         mr = readl_relaxed(ipcc->reg_proc + IPCC_XMR);
  93
  94         /* search for unmasked 'channel occupied' */
  95         status = tosr & FIELD_GET(RX_BIT_MASK, ~mr);
  96
  97         for (chan = 0; chan < ipcc->n_chans; chan++) {
  98                 if (!(status & (1 << chan)))
  99                         continue;
 100
 101                 dev_dbg(dev, "%s: chan:%d rx\n", __func__, chan);
 102
 103                 mbox_chan_received_data(&ipcc->controller.chans[chan], NULL);
 104
 105                 stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XSCR,
 106                                     RX_BIT_CHAN(chan));
 107
 108                 ret = IRQ_HANDLED;
 109         }
 110
 111         return ret;
 112 }
 113
 114 static irqreturn_t stm32_ipcc_tx_irq(int irq, void *data)
 115 {
 116         struct stm32_ipcc *ipcc = data;
 117         struct device *dev = ipcc->controller.dev;
 118         u32 status, mr, tosr, chan;
 119         irqreturn_t ret = IRQ_NONE;
 120
 121         tosr = readl_relaxed(ipcc->reg_proc + IPCC_XTOYSR);
 122         mr = readl_relaxed(ipcc->reg_proc + IPCC_XMR);
 123
 124         /* search for unmasked 'channel free' */
 125         status = ~tosr & FIELD_GET(TX_BIT_MASK, ~mr);
 126
 127         for (chan = 0; chan < ipcc->n_chans ; chan++) {
 128                 if (!(status & (1 << chan)))
 129                         continue;
 130
 131                 dev_dbg(dev, "%s: chan:%d tx\n", __func__, chan);
 132
 133                 /* mask 'tx channel free' interrupt */
 134                 stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
 135                                     TX_BIT_CHAN(chan));
 136
 137                 mbox_chan_txdone(&ipcc->controller.chans[chan], 0);
 138
 139                 ret = IRQ_HANDLED;
 140         }
 141
 142         return ret;
 143 }
 144
 145 static int stm32_ipcc_send_data(struct mbox_chan *link, void *data)
 146 {
 147         unsigned int chan = (unsigned int)link->con_priv;
 148         struct stm32_ipcc *ipcc = container_of(link->mbox, struct stm32_ipcc,
 149                                                controller);
 150
 151         dev_dbg(ipcc->controller.dev, "%s: chan:%d\n", __func__, chan);
 152
 153         /* set channel n occupied */
 154         stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XSCR,
 155                             TX_BIT_CHAN(chan));
 156
 157         /* unmask 'tx channel free' interrupt */
 158         stm32_ipcc_clr_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
 159                             TX_BIT_CHAN(chan));
 160
 161         return 0;
 162 }
 163
 164 static int stm32_ipcc_startup(struct mbox_chan *link)
 165 {
 166         unsigned int chan = (unsigned int)link->con_priv;
 167         struct stm32_ipcc *ipcc = container_of(link->mbox, struct stm32_ipcc,
 168                                                controller);
 169         int ret;
 170
 171         ret = clk_prepare_enable(ipcc->clk);
 172         if (ret) {
 173                 dev_err(ipcc->controller.dev, "can not enable the clock\n");
 174                 return ret;
 175         }
 176
 177         /* unmask 'rx channel occupied' interrupt */
 178         stm32_ipcc_clr_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
 179                             RX_BIT_CHAN(chan));
 180
 181         return 0;
 182 }
 183
 184 static void stm32_ipcc_shutdown(struct mbox_chan *link)
 185 {
 186         unsigned int chan = (unsigned int)link->con_priv;
 187         struct stm32_ipcc *ipcc = container_of(link->mbox, struct stm32_ipcc,
 188                                                controller);
 189
 190         /* mask rx/tx interrupt */
 191         stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
 192                             RX_BIT_CHAN(chan) | TX_BIT_CHAN(chan));
 193
 194         clk_disable_unprepare(ipcc->clk);
 195 }
 196
 197 static const struct mbox_chan_ops stm32_ipcc_ops = {
 198         .send_data      = stm32_ipcc_send_data,
 199         .startup        = stm32_ipcc_startup,
 200         .shutdown       = stm32_ipcc_shutdown,
 201 };
 202
 203 static int stm32_ipcc_probe(struct platform_device *pdev)
 204 {
 205         struct device *dev = &pdev->dev;
 206         struct device_node *np = dev->of_node;
 207         struct stm32_ipcc *ipcc;
 208         struct resource *res;
 209         unsigned int 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         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 239         ipcc->reg_base = devm_ioremap_resource(dev, res);
 240         if (IS_ERR(ipcc->reg_base))
 241                 return PTR_ERR(ipcc->reg_base);
 242
 243         ipcc->reg_proc = ipcc->reg_base + ipcc->proc_id * IPCC_PROC_OFFST;
 244
 245         /* clock */
 246         ipcc->clk = devm_clk_get(dev, NULL);
 247         if (IS_ERR(ipcc->clk))
 248                 return PTR_ERR(ipcc->clk);
 249
 250         ret = clk_prepare_enable(ipcc->clk);
 251         if (ret) {
 252                 dev_err(dev, "can not enable the clock\n");
 253                 return ret;
 254         }
 255
 256         /* irq */
 257         for (i = 0; i < IPCC_IRQ_NUM; i++) {
 258                 ipcc->irqs[i] = platform_get_irq_byname(pdev, irq_name[i]);
 259                 if (ipcc->irqs[i] < 0) {
 260                         if (ipcc->irqs[i] != -EPROBE_DEFER)
 261                                 dev_err(dev, "no IRQ specified %s\n",
 262                                         irq_name[i]);
 263                         ret = ipcc->irqs[i];
 264                         goto err_clk;
 265                 }
 266
 267                 ret = devm_request_threaded_irq(dev, ipcc->irqs[i], NULL,
 268                                                 irq_thread[i], IRQF_ONESHOT,
 269                                                 dev_name(dev), ipcc);
 270                 if (ret) {
 271                         dev_err(dev, "failed to request irq %d (%d)\n", i, ret);
 272                         goto err_clk;
 273                 }
 274         }
 275
 276         /* mask and enable rx/tx irq */
 277         stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
 278                             RX_BIT_MASK | TX_BIT_MASK);
 279         stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XCR,
 280                             XCR_RXOIE | XCR_TXOIE);
 281
 282         /* wakeup */
 283         if (of_property_read_bool(np, "wakeup-source")) {
 284                 device_set_wakeup_capable(dev, true);
 285
 286                 ret = dev_pm_set_wake_irq(dev, ipcc->irqs[IPCC_IRQ_RX]);
 287                 if (ret) {
 288                         dev_err(dev, "Failed to set wake up irq\n");
 289                         goto err_init_wkp;
 290                 }
 291         }
 292
 293         /* mailbox controller */
 294         ipcc->n_chans = readl_relaxed(ipcc->reg_base + IPCC_HWCFGR);
 295         ipcc->n_chans &= IPCFGR_CHAN_MASK;
 296
 297         ipcc->controller.dev = dev;
 298         ipcc->controller.txdone_irq = true;
 299         ipcc->controller.ops = &stm32_ipcc_ops;
 300         ipcc->controller.num_chans = ipcc->n_chans;
 301         ipcc->controller.chans = devm_kcalloc(dev, ipcc->controller.num_chans,
 302                                               sizeof(*ipcc->controller.chans),
 303                                               GFP_KERNEL);
 304         if (!ipcc->controller.chans) {
 305                 ret = -ENOMEM;
 306                 goto err_irq_wkp;
 307         }
 308
 309         for (i = 0; i < ipcc->controller.num_chans; i++)
 310                 ipcc->controller.chans[i].con_priv = (void *)i;
 311
 312         ret = devm_mbox_controller_register(dev, &ipcc->controller);
 313         if (ret)
 314                 goto err_irq_wkp;
 315
 316         platform_set_drvdata(pdev, ipcc);
 317
 318         ip_ver = readl_relaxed(ipcc->reg_base + IPCC_VER);
 319
 320         dev_info(dev, "ipcc rev:%ld.%ld enabled, %d chans, proc %d\n",
 321                  FIELD_GET(VER_MAJREV_MASK, ip_ver),
 322                  FIELD_GET(VER_MINREV_MASK, ip_ver),
 323                  ipcc->controller.num_chans, ipcc->proc_id);
 324
 325         clk_disable_unprepare(ipcc->clk);
 326         return 0;
 327
 328 err_irq_wkp:
 329         if (of_property_read_bool(np, "wakeup-source"))
 330                 dev_pm_clear_wake_irq(dev);
 331 err_init_wkp:
 332         device_set_wakeup_capable(dev, false);
 333 err_clk:
 334         clk_disable_unprepare(ipcc->clk);
 335         return ret;
 336 }
 337
 338 static int stm32_ipcc_remove(struct platform_device *pdev)
 339 {
 340         struct device *dev = &pdev->dev;
 341
 342         if (of_property_read_bool(dev->of_node, "wakeup-source"))
 343                 dev_pm_clear_wake_irq(&pdev->dev);
 344
 345         device_set_wakeup_capable(dev, false);
 346
 347         return 0;
 348 }
 349
 350 #ifdef CONFIG_PM_SLEEP
 351 static int stm32_ipcc_suspend(struct device *dev)
 352 {
 353         struct stm32_ipcc *ipcc = dev_get_drvdata(dev);
 354
 355         ipcc->xmr = readl_relaxed(ipcc->reg_proc + IPCC_XMR);
 356         ipcc->xcr = readl_relaxed(ipcc->reg_proc + IPCC_XCR);
 357
 358         return 0;
 359 }
 360
 361 static int stm32_ipcc_resume(struct device *dev)
 362 {
 363         struct stm32_ipcc *ipcc = dev_get_drvdata(dev);
 364
 365         writel_relaxed(ipcc->xmr, ipcc->reg_proc + IPCC_XMR);
 366         writel_relaxed(ipcc->xcr, ipcc->reg_proc + IPCC_XCR);
 367
 368         return 0;
 369 }
 370 #endif
 371
 372 static SIMPLE_DEV_PM_OPS(stm32_ipcc_pm_ops,
 373                          stm32_ipcc_suspend, stm32_ipcc_resume);
 374
 375 static const struct of_device_id stm32_ipcc_of_match[] = {
 376         { .compatible = "st,stm32mp1-ipcc" },
 377         {},
 378 };
 379 MODULE_DEVICE_TABLE(of, stm32_ipcc_of_match);
 380
 381 static struct platform_driver stm32_ipcc_driver = {
 382         .driver = {
 383                 .name = "stm32-ipcc",
 384                 .pm = &stm32_ipcc_pm_ops,
 385                 .of_match_table = stm32_ipcc_of_match,
 386         },
 387         .probe          = stm32_ipcc_probe,
 388         .remove         = stm32_ipcc_remove,
 389 };
 390
 391 module_platform_driver(stm32_ipcc_driver);
 392
 393 MODULE_AUTHOR("Ludovic Barre <ludovic.barre@st.com>");
 394 MODULE_AUTHOR("Fabien Dessenne <fabien.dessenne@st.com>");
 395 MODULE_DESCRIPTION("STM32 IPCC driver");
 396 MODULE_LICENSE("GPL v2");