1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright 2020 Samsung Electronics Co., Ltd. 4 * Copyright 2020 Google LLC. 5 * Copyright 2024 Linaro Ltd. 6 */ 7 8 #include <linux/bitops.h> 9 #include <linux/bits.h> 10 #include <linux/clk.h> 11 #include <linux/io.h> 12 #include <linux/mailbox_controller.h> 13 #include <linux/mailbox/exynos-message.h> 14 #include <linux/module.h> 15 #include <linux/of.h> 16 #include <linux/platform_device.h> 17 #include <linux/slab.h> 18 19 #define EXYNOS_MBOX_INTMR0 0x28 /* Interrupt Mask Register 0 */ 20 #define EXYNOS_MBOX_INTGR1 0x40 /* Interrupt Generation Register 1 */ 21 22 #define EXYNOS_MBOX_INTMR0_MASK GENMASK(15, 0) 23 #define EXYNOS_MBOX_INTGR1_MASK GENMASK(15, 0) 24 25 #define EXYNOS_MBOX_CHAN_COUNT HWEIGHT32(EXYNOS_MBOX_INTGR1_MASK) 26 27 /** 28 * struct exynos_mbox - driver's private data. 29 * @regs: mailbox registers base address. 30 * @mbox: pointer to the mailbox controller. 31 */ 32 struct exynos_mbox { 33 void __iomem *regs; 34 struct mbox_controller *mbox; 35 }; 36 37 static int exynos_mbox_send_data(struct mbox_chan *chan, void *data) 38 { 39 struct device *dev = chan->mbox->dev; 40 struct exynos_mbox *exynos_mbox = dev_get_drvdata(dev); 41 struct exynos_mbox_msg *msg = data; 42 43 if (msg->chan_id >= exynos_mbox->mbox->num_chans) { 44 dev_err(dev, "Invalid channel ID %d\n", msg->chan_id); 45 return -EINVAL; 46 } 47 48 if (msg->chan_type != EXYNOS_MBOX_CHAN_TYPE_DOORBELL) { 49 dev_err(dev, "Unsupported channel type [%d]\n", msg->chan_type); 50 return -EINVAL; 51 } 52 53 writel(BIT(msg->chan_id), exynos_mbox->regs + EXYNOS_MBOX_INTGR1); 54 55 return 0; 56 } 57 58 static const struct mbox_chan_ops exynos_mbox_chan_ops = { 59 .send_data = exynos_mbox_send_data, 60 }; 61 62 static struct mbox_chan *exynos_mbox_of_xlate(struct mbox_controller *mbox, 63 const struct of_phandle_args *sp) 64 { 65 int i; 66 67 if (sp->args_count != 0) 68 return ERR_PTR(-EINVAL); 69 70 /* 71 * Return the first available channel. When we don't pass the 72 * channel ID from device tree, each channel populated by the driver is 73 * just a software construct or a virtual channel. We use 'void *data' 74 * in send_data() to pass the channel identifiers. 75 */ 76 for (i = 0; i < mbox->num_chans; i++) 77 if (mbox->chans[i].cl == NULL) 78 return &mbox->chans[i]; 79 return ERR_PTR(-EINVAL); 80 } 81 82 static const struct of_device_id exynos_mbox_match[] = { 83 { .compatible = "google,gs101-mbox" }, 84 {}, 85 }; 86 MODULE_DEVICE_TABLE(of, exynos_mbox_match); 87 88 static int exynos_mbox_probe(struct platform_device *pdev) 89 { 90 struct device *dev = &pdev->dev; 91 struct exynos_mbox *exynos_mbox; 92 struct mbox_controller *mbox; 93 struct mbox_chan *chans; 94 struct clk *pclk; 95 96 exynos_mbox = devm_kzalloc(dev, sizeof(*exynos_mbox), GFP_KERNEL); 97 if (!exynos_mbox) 98 return -ENOMEM; 99 100 mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL); 101 if (!mbox) 102 return -ENOMEM; 103 104 chans = devm_kcalloc(dev, EXYNOS_MBOX_CHAN_COUNT, sizeof(*chans), 105 GFP_KERNEL); 106 if (!chans) 107 return -ENOMEM; 108 109 exynos_mbox->regs = devm_platform_ioremap_resource(pdev, 0); 110 if (IS_ERR(exynos_mbox->regs)) 111 return PTR_ERR(exynos_mbox->regs); 112 113 pclk = devm_clk_get_enabled(dev, "pclk"); 114 if (IS_ERR(pclk)) 115 return dev_err_probe(dev, PTR_ERR(pclk), 116 "Failed to enable clock.\n"); 117 118 mbox->num_chans = EXYNOS_MBOX_CHAN_COUNT; 119 mbox->chans = chans; 120 mbox->dev = dev; 121 mbox->ops = &exynos_mbox_chan_ops; 122 mbox->of_xlate = exynos_mbox_of_xlate; 123 124 exynos_mbox->mbox = mbox; 125 126 platform_set_drvdata(pdev, exynos_mbox); 127 128 /* Mask out all interrupts. We support just polling channels for now. */ 129 writel(EXYNOS_MBOX_INTMR0_MASK, exynos_mbox->regs + EXYNOS_MBOX_INTMR0); 130 131 return devm_mbox_controller_register(dev, mbox); 132 } 133 134 static struct platform_driver exynos_mbox_driver = { 135 .probe = exynos_mbox_probe, 136 .driver = { 137 .name = "exynos-acpm-mbox", 138 .of_match_table = exynos_mbox_match, 139 }, 140 }; 141 module_platform_driver(exynos_mbox_driver); 142 143 MODULE_AUTHOR("Tudor Ambarus <tudor.ambarus@linaro.org>"); 144 MODULE_DESCRIPTION("Samsung Exynos mailbox driver"); 145 MODULE_LICENSE("GPL"); 146