| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Nvidia GPU I2C controller Driver |
| * |
| * Copyright (C) 2018 NVIDIA Corporation. All rights reserved. |
| * Author: Ajay Gupta <ajayg@nvidia.com> |
| */ |
| #include <linux/delay.h> |
| #include <linux/i2c.h> |
| #include <linux/interrupt.h> |
| #include <linux/iopoll.h> |
| #include <linux/module.h> |
| #include <linux/pci.h> |
| #include <linux/platform_device.h> |
| #include <linux/pm.h> |
| #include <linux/pm_runtime.h> |
| |
| #include <asm/unaligned.h> |
| |
| /* 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; |
| struct i2c_client *ccgx_client; |
| }; |
| |
| 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) |
| { |
| u32 val; |
| int ret; |
| |
| ret = readl_poll_timeout(i2cd->regs + I2C_MST_CNTL, val, |
| !(val & I2C_MST_CNTL_CYCLE_TRIGGER) || |
| (val & I2C_MST_CNTL_STATUS) != I2C_MST_CNTL_STATUS_BUS_BUSY, |
| 500, 1000 * USEC_PER_MSEC); |
| |
| if (ret) { |
| 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; |
| bool send_stop = true; |
| int i, j; |
| |
| /* |
| * The controller supports maximum 4 byte read due to known |
| * limitation of sending STOP after every read. |
| */ |
| pm_runtime_get_sync(i2cd->dev); |
| 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 exit; |
| } else { |
| u8 addr = i2c_8bit_addr_from_msg(msgs + i); |
| |
| status = gpu_i2c_start(i2cd); |
| if (status < 0) { |
| if (i == 0) |
| send_stop = false; |
| goto exit; |
| } |
| |
| status = gpu_i2c_write(i2cd, addr); |
| if (status < 0) |
| goto exit; |
| |
| for (j = 0; j < msgs[i].len; j++) { |
| status = gpu_i2c_write(i2cd, msgs[i].buf[j]); |
| if (status < 0) |
| goto exit; |
| } |
| } |
| } |
| send_stop = false; |
| status = gpu_i2c_stop(i2cd); |
| if (status < 0) |
| goto exit; |
| |
| status = i; |
| exit: |
| if (send_stop) { |
| status2 = gpu_i2c_stop(i2cd); |
| if (status2 < 0) |
| dev_err(i2cd->dev, "i2c stop failed %d\n", status2); |
| } |
| pm_runtime_mark_last_busy(i2cd->dev); |
| pm_runtime_put_autosuspend(i2cd->dev); |
| return status; |
| } |
| |
| static const struct i2c_adapter_quirks gpu_i2c_quirks = { |
| .max_read_len = 4, |
| .max_comb_2nd_msg_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 const struct property_entry ccgx_props[] = { |
| /* Use FW built for NVIDIA (nv) only */ |
| PROPERTY_ENTRY_U16("ccgx,firmware-build", ('n' << 8) | 'v'), |
| { } |
| }; |
| |
| static int gpu_populate_client(struct gpu_i2c_dev *i2cd, int irq) |
| { |
| 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; |
| i2cd->gpu_ccgx_ucsi->properties = ccgx_props; |
| i2cd->ccgx_client = i2c_new_device(&i2cd->adapter, i2cd->gpu_ccgx_ucsi); |
| if (!i2cd->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; |
| } |
| |
| pm_runtime_set_autosuspend_delay(&pdev->dev, 3000); |
| pm_runtime_use_autosuspend(&pdev->dev); |
| pm_runtime_put_autosuspend(&pdev->dev); |
| pm_runtime_allow(&pdev->dev); |
| |
| 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); |
| |
| pm_runtime_get_noresume(i2cd->dev); |
| i2c_del_adapter(&i2cd->adapter); |
| pci_free_irq_vectors(pdev); |
| } |
| |
| /* |
| * We need gpu_i2c_suspend() even if it is stub, for runtime pm to work |
| * correctly. Without it, lspci shows runtime pm status as "D0" for the card. |
| * Documentation/power/pci.rst also insists for driver to provide this. |
| */ |
| static __maybe_unused int gpu_i2c_suspend(struct device *dev) |
| { |
| return 0; |
| } |
| |
| static __maybe_unused int gpu_i2c_resume(struct device *dev) |
| { |
| struct gpu_i2c_dev *i2cd = dev_get_drvdata(dev); |
| |
| gpu_enable_i2c_bus(i2cd); |
| /* |
| * Runtime resume ccgx client so that it can see for any |
| * connector change event. Old ccg firmware has known |
| * issue of not triggering interrupt when a device is |
| * connected to runtime resume the controller. |
| */ |
| pm_request_resume(&i2cd->ccgx_client->dev); |
| return 0; |
| } |
| |
| static UNIVERSAL_DEV_PM_OPS(gpu_i2c_driver_pm, gpu_i2c_suspend, 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 <ajayg@nvidia.com>"); |
| MODULE_DESCRIPTION("Nvidia GPU I2C controller Driver"); |
| MODULE_LICENSE("GPL v2"); |