// SPDX-License-Identifier: GPL-2.0 /* * Nvidia GPU I2C controller Driver * * Copyright (C) 2018 NVIDIA Corporation. All rights reserved. * Author: Ajay Gupta */ #include #include #include #include #include #include #include #include #include /* I2C definitions */ #define I2C_MST_CNTL 0x00 #define I2C_MST_CNTL_GEN_START BIT(0) #define I2C_MST_CNTL_GEN_STOP BIT(1) #define I2C_MST_CNTL_CMD_READ (1 << 2) #define I2C_MST_CNTL_CMD_WRITE (2 << 2) #define I2C_MST_CNTL_BURST_SIZE_SHIFT 6 #define I2C_MST_CNTL_GEN_NACK BIT(28) #define I2C_MST_CNTL_STATUS GENMASK(30, 29) #define I2C_MST_CNTL_STATUS_OKAY (0 << 29) #define I2C_MST_CNTL_STATUS_NO_ACK (1 << 29) #define I2C_MST_CNTL_STATUS_TIMEOUT (2 << 29) #define I2C_MST_CNTL_STATUS_BUS_BUSY (3 << 29) #define I2C_MST_CNTL_CYCLE_TRIGGER BIT(31) #define I2C_MST_ADDR 0x04 #define I2C_MST_I2C0_TIMING 0x08 #define I2C_MST_I2C0_TIMING_SCL_PERIOD_100KHZ 0x10e #define I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT 16 #define I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT_MAX 255 #define I2C_MST_I2C0_TIMING_TIMEOUT_CHECK BIT(24) #define I2C_MST_DATA 0x0c #define I2C_MST_HYBRID_PADCTL 0x20 #define I2C_MST_HYBRID_PADCTL_MODE_I2C BIT(0) #define I2C_MST_HYBRID_PADCTL_I2C_SCL_INPUT_RCV BIT(14) #define I2C_MST_HYBRID_PADCTL_I2C_SDA_INPUT_RCV BIT(15) struct gpu_i2c_dev { struct device *dev; void __iomem *regs; struct i2c_adapter adapter; struct i2c_board_info *gpu_ccgx_ucsi; }; static void gpu_enable_i2c_bus(struct gpu_i2c_dev *i2cd) { u32 val; /* enable I2C */ val = readl(i2cd->regs + I2C_MST_HYBRID_PADCTL); val |= I2C_MST_HYBRID_PADCTL_MODE_I2C | I2C_MST_HYBRID_PADCTL_I2C_SCL_INPUT_RCV | I2C_MST_HYBRID_PADCTL_I2C_SDA_INPUT_RCV; writel(val, i2cd->regs + I2C_MST_HYBRID_PADCTL); /* enable 100KHZ mode */ val = I2C_MST_I2C0_TIMING_SCL_PERIOD_100KHZ; val |= (I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT_MAX << I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT); val |= I2C_MST_I2C0_TIMING_TIMEOUT_CHECK; writel(val, i2cd->regs + I2C_MST_I2C0_TIMING); } static int gpu_i2c_check_status(struct gpu_i2c_dev *i2cd) { unsigned long target = jiffies + msecs_to_jiffies(1000); u32 val; do { val = readl(i2cd->regs + I2C_MST_CNTL); if (!(val & I2C_MST_CNTL_CYCLE_TRIGGER)) break; if ((val & I2C_MST_CNTL_STATUS) != I2C_MST_CNTL_STATUS_BUS_BUSY) break; usleep_range(500, 600); } while (time_is_after_jiffies(target)); if (time_is_before_jiffies(target)) { dev_err(i2cd->dev, "i2c timeout error %x\n", val); return -ETIMEDOUT; } val = readl(i2cd->regs + I2C_MST_CNTL); switch (val & I2C_MST_CNTL_STATUS) { case I2C_MST_CNTL_STATUS_OKAY: return 0; case I2C_MST_CNTL_STATUS_NO_ACK: return -ENXIO; case I2C_MST_CNTL_STATUS_TIMEOUT: return -ETIMEDOUT; default: return 0; } } static int gpu_i2c_read(struct gpu_i2c_dev *i2cd, u8 *data, u16 len) { int status; u32 val; val = I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_CMD_READ | (len << I2C_MST_CNTL_BURST_SIZE_SHIFT) | I2C_MST_CNTL_CYCLE_TRIGGER | I2C_MST_CNTL_GEN_NACK; writel(val, i2cd->regs + I2C_MST_CNTL); status = gpu_i2c_check_status(i2cd); if (status < 0) return status; val = readl(i2cd->regs + I2C_MST_DATA); switch (len) { case 1: data[0] = val; break; case 2: put_unaligned_be16(val, data); break; case 3: put_unaligned_be16(val >> 8, data); data[2] = val; break; case 4: put_unaligned_be32(val, data); break; default: break; } return status; } static int gpu_i2c_start(struct gpu_i2c_dev *i2cd) { writel(I2C_MST_CNTL_GEN_START, i2cd->regs + I2C_MST_CNTL); return gpu_i2c_check_status(i2cd); } static int gpu_i2c_stop(struct gpu_i2c_dev *i2cd) { writel(I2C_MST_CNTL_GEN_STOP, i2cd->regs + I2C_MST_CNTL); return gpu_i2c_check_status(i2cd); } static int gpu_i2c_write(struct gpu_i2c_dev *i2cd, u8 data) { u32 val; writel(data, i2cd->regs + I2C_MST_DATA); val = I2C_MST_CNTL_CMD_WRITE | (1 << I2C_MST_CNTL_BURST_SIZE_SHIFT); writel(val, i2cd->regs + I2C_MST_CNTL); return gpu_i2c_check_status(i2cd); } static int gpu_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { struct gpu_i2c_dev *i2cd = i2c_get_adapdata(adap); int status, status2; int i, j; /* * The controller supports maximum 4 byte read due to known * limitation of sending STOP after every read. */ for (i = 0; i < num; i++) { if (msgs[i].flags & I2C_M_RD) { /* program client address before starting read */ writel(msgs[i].addr, i2cd->regs + I2C_MST_ADDR); /* gpu_i2c_read has implicit start */ status = gpu_i2c_read(i2cd, msgs[i].buf, msgs[i].len); if (status < 0) goto stop; } else { u8 addr = i2c_8bit_addr_from_msg(msgs + i); status = gpu_i2c_start(i2cd); if (status < 0) { if (i == 0) return status; goto stop; } status = gpu_i2c_write(i2cd, addr); if (status < 0) goto stop; for (j = 0; j < msgs[i].len; j++) { status = gpu_i2c_write(i2cd, msgs[i].buf[j]); if (status < 0) goto stop; } } } status = gpu_i2c_stop(i2cd); if (status < 0) return status; return i; stop: status2 = gpu_i2c_stop(i2cd); if (status2 < 0) dev_err(i2cd->dev, "i2c stop failed %d\n", status2); return status; } static const struct i2c_adapter_quirks gpu_i2c_quirks = { .max_read_len = 4, .flags = I2C_AQ_COMB_WRITE_THEN_READ, }; static u32 gpu_i2c_functionality(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; } static const struct i2c_algorithm gpu_i2c_algorithm = { .master_xfer = gpu_i2c_master_xfer, .functionality = gpu_i2c_functionality, }; /* * This driver is for Nvidia GPU cards with USB Type-C interface. * We want to identify the cards using vendor ID and class code only * to avoid dependency of adding product id for any new card which * requires this driver. * Currently there is no class code defined for UCSI device over PCI * so using UNKNOWN class for now and it will be updated when UCSI * over PCI gets a class code. * There is no other NVIDIA cards with UNKNOWN class code. Even if the * driver gets loaded for an undesired card then eventually i2c_read() * (initiated from UCSI i2c_client) will timeout or UCSI commands will * timeout. */ #define PCI_CLASS_SERIAL_UNKNOWN 0x0c80 static const struct pci_device_id gpu_i2c_ids[] = { { PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, PCI_CLASS_SERIAL_UNKNOWN << 8, 0xffffff00}, { } }; MODULE_DEVICE_TABLE(pci, gpu_i2c_ids); static int gpu_populate_client(struct gpu_i2c_dev *i2cd, int irq) { struct i2c_client *ccgx_client; i2cd->gpu_ccgx_ucsi = devm_kzalloc(i2cd->dev, sizeof(*i2cd->gpu_ccgx_ucsi), GFP_KERNEL); if (!i2cd->gpu_ccgx_ucsi) return -ENOMEM; strlcpy(i2cd->gpu_ccgx_ucsi->type, "ccgx-ucsi", sizeof(i2cd->gpu_ccgx_ucsi->type)); i2cd->gpu_ccgx_ucsi->addr = 0x8; i2cd->gpu_ccgx_ucsi->irq = irq; ccgx_client = i2c_new_device(&i2cd->adapter, i2cd->gpu_ccgx_ucsi); if (!ccgx_client) return -ENODEV; return 0; } static int gpu_i2c_probe(struct pci_dev *pdev, const struct pci_device_id *id) { struct gpu_i2c_dev *i2cd; int status; i2cd = devm_kzalloc(&pdev->dev, sizeof(*i2cd), GFP_KERNEL); if (!i2cd) return -ENOMEM; i2cd->dev = &pdev->dev; dev_set_drvdata(&pdev->dev, i2cd); status = pcim_enable_device(pdev); if (status < 0) { dev_err(&pdev->dev, "pcim_enable_device failed %d\n", status); return status; } pci_set_master(pdev); i2cd->regs = pcim_iomap(pdev, 0, 0); if (!i2cd->regs) { dev_err(&pdev->dev, "pcim_iomap failed\n"); return -ENOMEM; } status = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI); if (status < 0) { dev_err(&pdev->dev, "pci_alloc_irq_vectors err %d\n", status); return status; } gpu_enable_i2c_bus(i2cd); i2c_set_adapdata(&i2cd->adapter, i2cd); i2cd->adapter.owner = THIS_MODULE; strlcpy(i2cd->adapter.name, "NVIDIA GPU I2C adapter", sizeof(i2cd->adapter.name)); i2cd->adapter.algo = &gpu_i2c_algorithm; i2cd->adapter.quirks = &gpu_i2c_quirks; i2cd->adapter.dev.parent = &pdev->dev; status = i2c_add_adapter(&i2cd->adapter); if (status < 0) goto free_irq_vectors; status = gpu_populate_client(i2cd, pdev->irq); if (status < 0) { dev_err(&pdev->dev, "gpu_populate_client failed %d\n", status); goto del_adapter; } return 0; del_adapter: i2c_del_adapter(&i2cd->adapter); free_irq_vectors: pci_free_irq_vectors(pdev); return status; } static void gpu_i2c_remove(struct pci_dev *pdev) { struct gpu_i2c_dev *i2cd = dev_get_drvdata(&pdev->dev); i2c_del_adapter(&i2cd->adapter); pci_free_irq_vectors(pdev); } static int gpu_i2c_resume(struct device *dev) { struct gpu_i2c_dev *i2cd = dev_get_drvdata(dev); gpu_enable_i2c_bus(i2cd); return 0; } static UNIVERSAL_DEV_PM_OPS(gpu_i2c_driver_pm, NULL, gpu_i2c_resume, NULL); static struct pci_driver gpu_i2c_driver = { .name = "nvidia-gpu", .id_table = gpu_i2c_ids, .probe = gpu_i2c_probe, .remove = gpu_i2c_remove, .driver = { .pm = &gpu_i2c_driver_pm, }, }; module_pci_driver(gpu_i2c_driver); MODULE_AUTHOR("Ajay Gupta "); MODULE_DESCRIPTION("Nvidia GPU I2C controller Driver"); MODULE_LICENSE("GPL v2");