mailbox-altera.c 8.5 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * Copyright Altera Corporation (C) 2013-2014. All rights reserved
  4. */
  5. #include <linux/device.h>
  6. #include <linux/interrupt.h>
  7. #include <linux/io.h>
  8. #include <linux/kernel.h>
  9. #include <linux/mailbox_controller.h>
  10. #include <linux/module.h>
  11. #include <linux/of.h>
  12. #include <linux/platform_device.h>
  13. #define DRIVER_NAME "altera-mailbox"
  14. #define MAILBOX_CMD_REG 0x00
  15. #define MAILBOX_PTR_REG 0x04
  16. #define MAILBOX_STS_REG 0x08
  17. #define MAILBOX_INTMASK_REG 0x0C
  18. #define INT_PENDING_MSK 0x1
  19. #define INT_SPACE_MSK 0x2
  20. #define STS_PENDING_MSK 0x1
  21. #define STS_FULL_MSK 0x2
  22. #define STS_FULL_OFT 0x1
  23. #define MBOX_PENDING(status) (((status) & STS_PENDING_MSK))
  24. #define MBOX_FULL(status) (((status) & STS_FULL_MSK) >> STS_FULL_OFT)
  25. enum altera_mbox_msg {
  26. MBOX_CMD = 0,
  27. MBOX_PTR,
  28. };
  29. #define MBOX_POLLING_MS 5 /* polling interval 5ms */
  30. struct altera_mbox {
  31. bool is_sender; /* 1-sender, 0-receiver */
  32. bool intr_mode;
  33. int irq;
  34. void __iomem *mbox_base;
  35. struct device *dev;
  36. struct mbox_controller controller;
  37. /* If the controller supports only RX polling mode */
  38. struct timer_list rxpoll_timer;
  39. struct mbox_chan *chan;
  40. };
  41. static struct altera_mbox *mbox_chan_to_altera_mbox(struct mbox_chan *chan)
  42. {
  43. if (!chan || !chan->con_priv)
  44. return NULL;
  45. return (struct altera_mbox *)chan->con_priv;
  46. }
  47. static inline int altera_mbox_full(struct altera_mbox *mbox)
  48. {
  49. u32 status;
  50. status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
  51. return MBOX_FULL(status);
  52. }
  53. static inline int altera_mbox_pending(struct altera_mbox *mbox)
  54. {
  55. u32 status;
  56. status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
  57. return MBOX_PENDING(status);
  58. }
  59. static void altera_mbox_rx_intmask(struct altera_mbox *mbox, bool enable)
  60. {
  61. u32 mask;
  62. mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
  63. if (enable)
  64. mask |= INT_PENDING_MSK;
  65. else
  66. mask &= ~INT_PENDING_MSK;
  67. writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
  68. }
  69. static void altera_mbox_tx_intmask(struct altera_mbox *mbox, bool enable)
  70. {
  71. u32 mask;
  72. mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
  73. if (enable)
  74. mask |= INT_SPACE_MSK;
  75. else
  76. mask &= ~INT_SPACE_MSK;
  77. writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
  78. }
  79. static bool altera_mbox_is_sender(struct altera_mbox *mbox)
  80. {
  81. u32 reg;
  82. /* Write a magic number to PTR register and read back this register.
  83. * This register is read-write if it is a sender.
  84. */
  85. #define MBOX_MAGIC 0xA5A5AA55
  86. writel_relaxed(MBOX_MAGIC, mbox->mbox_base + MAILBOX_PTR_REG);
  87. reg = readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
  88. if (reg == MBOX_MAGIC) {
  89. /* Clear to 0 */
  90. writel_relaxed(0, mbox->mbox_base + MAILBOX_PTR_REG);
  91. return true;
  92. }
  93. return false;
  94. }
  95. static void altera_mbox_rx_data(struct mbox_chan *chan)
  96. {
  97. struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
  98. u32 data[2];
  99. if (altera_mbox_pending(mbox)) {
  100. data[MBOX_PTR] =
  101. readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
  102. data[MBOX_CMD] =
  103. readl_relaxed(mbox->mbox_base + MAILBOX_CMD_REG);
  104. mbox_chan_received_data(chan, (void *)data);
  105. }
  106. }
  107. static void altera_mbox_poll_rx(struct timer_list *t)
  108. {
  109. struct altera_mbox *mbox = from_timer(mbox, t, rxpoll_timer);
  110. altera_mbox_rx_data(mbox->chan);
  111. mod_timer(&mbox->rxpoll_timer,
  112. jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
  113. }
  114. static irqreturn_t altera_mbox_tx_interrupt(int irq, void *p)
  115. {
  116. struct mbox_chan *chan = (struct mbox_chan *)p;
  117. struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
  118. altera_mbox_tx_intmask(mbox, false);
  119. mbox_chan_txdone(chan, 0);
  120. return IRQ_HANDLED;
  121. }
  122. static irqreturn_t altera_mbox_rx_interrupt(int irq, void *p)
  123. {
  124. struct mbox_chan *chan = (struct mbox_chan *)p;
  125. altera_mbox_rx_data(chan);
  126. return IRQ_HANDLED;
  127. }
  128. static int altera_mbox_startup_sender(struct mbox_chan *chan)
  129. {
  130. int ret;
  131. struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
  132. if (mbox->intr_mode) {
  133. ret = request_irq(mbox->irq, altera_mbox_tx_interrupt, 0,
  134. DRIVER_NAME, chan);
  135. if (unlikely(ret)) {
  136. dev_err(mbox->dev,
  137. "failed to register mailbox interrupt:%d\n",
  138. ret);
  139. return ret;
  140. }
  141. }
  142. return 0;
  143. }
  144. static int altera_mbox_startup_receiver(struct mbox_chan *chan)
  145. {
  146. int ret;
  147. struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
  148. if (mbox->intr_mode) {
  149. ret = request_irq(mbox->irq, altera_mbox_rx_interrupt, 0,
  150. DRIVER_NAME, chan);
  151. if (unlikely(ret)) {
  152. mbox->intr_mode = false;
  153. goto polling; /* use polling if failed */
  154. }
  155. altera_mbox_rx_intmask(mbox, true);
  156. return 0;
  157. }
  158. polling:
  159. /* Setup polling timer */
  160. mbox->chan = chan;
  161. timer_setup(&mbox->rxpoll_timer, altera_mbox_poll_rx, 0);
  162. mod_timer(&mbox->rxpoll_timer,
  163. jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
  164. return 0;
  165. }
  166. static int altera_mbox_send_data(struct mbox_chan *chan, void *data)
  167. {
  168. struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
  169. u32 *udata = (u32 *)data;
  170. if (!mbox || !data)
  171. return -EINVAL;
  172. if (!mbox->is_sender) {
  173. dev_warn(mbox->dev,
  174. "failed to send. This is receiver mailbox.\n");
  175. return -EINVAL;
  176. }
  177. if (altera_mbox_full(mbox))
  178. return -EBUSY;
  179. /* Enable interrupt before send */
  180. if (mbox->intr_mode)
  181. altera_mbox_tx_intmask(mbox, true);
  182. /* Pointer register must write before command register */
  183. writel_relaxed(udata[MBOX_PTR], mbox->mbox_base + MAILBOX_PTR_REG);
  184. writel_relaxed(udata[MBOX_CMD], mbox->mbox_base + MAILBOX_CMD_REG);
  185. return 0;
  186. }
  187. static bool altera_mbox_last_tx_done(struct mbox_chan *chan)
  188. {
  189. struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
  190. /* Return false if mailbox is full */
  191. return altera_mbox_full(mbox) ? false : true;
  192. }
  193. static bool altera_mbox_peek_data(struct mbox_chan *chan)
  194. {
  195. struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
  196. return altera_mbox_pending(mbox) ? true : false;
  197. }
  198. static int altera_mbox_startup(struct mbox_chan *chan)
  199. {
  200. struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
  201. int ret = 0;
  202. if (!mbox)
  203. return -EINVAL;
  204. if (mbox->is_sender)
  205. ret = altera_mbox_startup_sender(chan);
  206. else
  207. ret = altera_mbox_startup_receiver(chan);
  208. return ret;
  209. }
  210. static void altera_mbox_shutdown(struct mbox_chan *chan)
  211. {
  212. struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
  213. if (mbox->intr_mode) {
  214. /* Unmask all interrupt masks */
  215. writel_relaxed(~0, mbox->mbox_base + MAILBOX_INTMASK_REG);
  216. free_irq(mbox->irq, chan);
  217. } else if (!mbox->is_sender) {
  218. del_timer_sync(&mbox->rxpoll_timer);
  219. }
  220. }
  221. static const struct mbox_chan_ops altera_mbox_ops = {
  222. .send_data = altera_mbox_send_data,
  223. .startup = altera_mbox_startup,
  224. .shutdown = altera_mbox_shutdown,
  225. .last_tx_done = altera_mbox_last_tx_done,
  226. .peek_data = altera_mbox_peek_data,
  227. };
  228. static int altera_mbox_probe(struct platform_device *pdev)
  229. {
  230. struct altera_mbox *mbox;
  231. struct resource *regs;
  232. struct mbox_chan *chans;
  233. int ret;
  234. mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox),
  235. GFP_KERNEL);
  236. if (!mbox)
  237. return -ENOMEM;
  238. /* Allocated one channel */
  239. chans = devm_kzalloc(&pdev->dev, sizeof(*chans), GFP_KERNEL);
  240. if (!chans)
  241. return -ENOMEM;
  242. regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  243. mbox->mbox_base = devm_ioremap_resource(&pdev->dev, regs);
  244. if (IS_ERR(mbox->mbox_base))
  245. return PTR_ERR(mbox->mbox_base);
  246. /* Check is it a sender or receiver? */
  247. mbox->is_sender = altera_mbox_is_sender(mbox);
  248. mbox->irq = platform_get_irq(pdev, 0);
  249. if (mbox->irq >= 0)
  250. mbox->intr_mode = true;
  251. mbox->dev = &pdev->dev;
  252. /* Hardware supports only one channel. */
  253. chans[0].con_priv = mbox;
  254. mbox->controller.dev = mbox->dev;
  255. mbox->controller.num_chans = 1;
  256. mbox->controller.chans = chans;
  257. mbox->controller.ops = &altera_mbox_ops;
  258. if (mbox->is_sender) {
  259. if (mbox->intr_mode) {
  260. mbox->controller.txdone_irq = true;
  261. } else {
  262. mbox->controller.txdone_poll = true;
  263. mbox->controller.txpoll_period = MBOX_POLLING_MS;
  264. }
  265. }
  266. ret = devm_mbox_controller_register(&pdev->dev, &mbox->controller);
  267. if (ret) {
  268. dev_err(&pdev->dev, "Register mailbox failed\n");
  269. goto err;
  270. }
  271. platform_set_drvdata(pdev, mbox);
  272. err:
  273. return ret;
  274. }
  275. static const struct of_device_id altera_mbox_match[] = {
  276. { .compatible = "altr,mailbox-1.0" },
  277. { /* Sentinel */ }
  278. };
  279. MODULE_DEVICE_TABLE(of, altera_mbox_match);
  280. static struct platform_driver altera_mbox_driver = {
  281. .probe = altera_mbox_probe,
  282. .driver = {
  283. .name = DRIVER_NAME,
  284. .of_match_table = altera_mbox_match,
  285. },
  286. };
  287. module_platform_driver(altera_mbox_driver);
  288. MODULE_LICENSE("GPL v2");
  289. MODULE_DESCRIPTION("Altera mailbox specific functions");
  290. MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
  291. MODULE_ALIAS("platform:altera-mailbox");