| Message ID | 1536263533-16660-1-git-send-email-ajayg@nvidia.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v8,1/2] i2c: buses: add i2c bus driver for NVIDIA GPU | expand |
On 2018-09-06 21:52, Ajay Gupta wrote: > Latest NVIDIA GPU card has USB Type-C interface. There is a > Type-C controller which can be accessed over I2C. > > This driver adds I2C bus driver to communicate with Type-C controller. > I2C client driver will be part of USB Type-C UCSI driver. > > Signed-off-by: Ajay Gupta <ajayg@nvidia.com> > Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> > Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> > --- > Changes from v1 -> v2 > None > Changes from v2 -> v3 > Fixed review comments from Andy and Thierry > Rename i2c-gpu.c -> i2c-nvidia-gpu.c > Changes from v3 -> v4 > Fixed review comments from Andy > Changes from v4 -> v5 > Fixed review comments from Andy > Changes from v5 -> v6 > None > Changes from v6 -> v7 -> v8 > Fixed review comments from Peter > - Add implicit STOP for last write message > - Add i2c_adapter_quirks with max_read_len and > I2C_AQ_COMB flags > > Documentation/i2c/busses/i2c-nvidia-gpu | 18 ++ > MAINTAINERS | 7 + > drivers/i2c/busses/Kconfig | 9 + > drivers/i2c/busses/Makefile | 1 + > drivers/i2c/busses/i2c-nvidia-gpu.c | 400 ++++++++++++++++++++++++++++++++ > 5 files changed, 435 insertions(+) > create mode 100644 Documentation/i2c/busses/i2c-nvidia-gpu > create mode 100644 drivers/i2c/busses/i2c-nvidia-gpu.c > > diff --git a/Documentation/i2c/busses/i2c-nvidia-gpu b/Documentation/i2c/busses/i2c-nvidia-gpu > new file mode 100644 > index 0000000..31884d2 > --- /dev/null > +++ b/Documentation/i2c/busses/i2c-nvidia-gpu > @@ -0,0 +1,18 @@ > +Kernel driver i2c-nvidia-gpu > + > +Datasheet: not publicly available. > + > +Authors: > + Ajay Gupta <ajayg@nvidia.com> > + > +Description > +----------- > + > +i2c-nvidia-gpu is a driver for I2C controller included in NVIDIA Turing > +and later GPUs and it is used to communicate with Type-C controller on GPUs. > + > +If your 'lspci -v' listing shows something like the following, > + > +01:00.3 Serial bus controller [0c80]: NVIDIA Corporation Device 1ad9 (rev a1) > + > +then this driver should support the I2C controller of your GPU. > diff --git a/MAINTAINERS b/MAINTAINERS > index 9ad052a..2d1c5a1 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -6797,6 +6797,13 @@ L: linux-acpi@vger.kernel.org > S: Maintained > F: drivers/i2c/i2c-core-acpi.c > > +I2C CONTROLLER DRIVER FOR NVIDIA GPU > +M: Ajay Gupta <ajayg@nvidia.com> > +L: linux-i2c@vger.kernel.org > +S: Maintained > +F: Documentation/i2c/busses/i2c-nvidia-gpu > +F: drivers/i2c/busses/i2c-nvidia-gpu.c > + > I2C MUXES > M: Peter Rosin <peda@axentia.se> > L: linux-i2c@vger.kernel.org > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig > index 451d4ae..eed827b 100644 > --- a/drivers/i2c/busses/Kconfig > +++ b/drivers/i2c/busses/Kconfig > @@ -224,6 +224,15 @@ config I2C_NFORCE2_S4985 > This driver can also be built as a module. If so, the module > will be called i2c-nforce2-s4985. > > +config I2C_NVIDIA_GPU > + tristate "NVIDIA GPU I2C controller" > + depends on PCI > + help > + If you say yes to this option, support will be included for the > + NVIDIA GPU I2C controller which is used to communicate with the GPU's > + Type-C controller. This driver can also be built as a module called > + i2c-nvidia-gpu. > + > config I2C_SIS5595 > tristate "SiS 5595" > depends on PCI > diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile > index 18b26af..d499813 100644 > --- a/drivers/i2c/busses/Makefile > +++ b/drivers/i2c/busses/Makefile > @@ -140,5 +140,6 @@ obj-$(CONFIG_I2C_SIBYTE) += i2c-sibyte.o > obj-$(CONFIG_I2C_XGENE_SLIMPRO) += i2c-xgene-slimpro.o > obj-$(CONFIG_SCx200_ACB) += scx200_acb.o > obj-$(CONFIG_I2C_FSI) += i2c-fsi.o > +obj-$(CONFIG_I2C_NVIDIA_GPU) += i2c-nvidia-gpu.o > > ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG > diff --git a/drivers/i2c/busses/i2c-nvidia-gpu.c b/drivers/i2c/busses/i2c-nvidia-gpu.c > new file mode 100644 > index 0000000..4816a31 > --- /dev/null > +++ b/drivers/i2c/busses/i2c-nvidia-gpu.c > @@ -0,0 +1,400 @@ > +// 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/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_NONE (0 << 2) > +#define I2C_MST_CNTL_CMD_READ (1 << 2) > +#define I2C_MST_CNTL_CMD_WRITE (2 << 2) > +#define I2C_MST_CNTL_GEN_RAB BIT(4) > +#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_ADDR_DAB 0 > + > +#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_client *client; > + struct mutex mutex; /* to sync read/write */ > + bool do_start; I don't think do_start belongs here. master_xfer should always start with a start, either explicit if the first message is a write or implicit if it's a read. The is no value in keeping this state between different calls to master_xfer. It's actually error-prone, see below. > +}; > + > +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(1000, 2000); > + } while (time_is_after_jiffies(target)); > + if (time_is_before_jiffies(target)) { > + dev_err(i2cd->dev, "i2c timeout error %x\n", val); > + return -EIO; > + } > + > + 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 -EIO; > + case I2C_MST_CNTL_STATUS_TIMEOUT: > + return -ETIME; > + case I2C_MST_CNTL_STATUS_BUS_BUSY: > + return -EBUSY; > + 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_GEN_STOP | > + I2C_MST_CNTL_CMD_READ | (len << I2C_MST_CNTL_BURST_SIZE_SHIFT) | > + I2C_MST_CNTL_CYCLE_TRIGGER | I2C_MST_CNTL_GEN_NACK; > + val &= ~I2C_MST_CNTL_GEN_RAB; > + 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, u16 addr) > +{ > + u32 val; > + > + val = addr << I2C_MST_ADDR_DAB; > + writel(val, i2cd->regs + I2C_MST_ADDR); > + > + val = I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_CMD_NONE | > + I2C_MST_CNTL_GEN_NACK; > + val &= ~(I2C_MST_CNTL_GEN_STOP | I2C_MST_CNTL_GEN_RAB); > + writel(val, i2cd->regs + I2C_MST_CNTL); > + > + return gpu_i2c_check_status(i2cd); > +} > + > +static int gpu_i2c_stop(struct gpu_i2c_dev *i2cd) > +{ > + u32 val; > + > + val = I2C_MST_CNTL_GEN_STOP | I2C_MST_CNTL_CMD_NONE | > + I2C_MST_CNTL_GEN_NACK; > + val &= ~(I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_GEN_RAB); > + writel(val, 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) | > + I2C_MST_CNTL_GEN_NACK; > + val &= ~(I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_GEN_STOP | > + I2C_MST_CNTL_GEN_RAB); > + 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; > + int i, j; > + > + mutex_lock(&i2cd->mutex); > + for (i = 0; i < num; i++) { > + if (msgs[i].flags & I2C_M_RD) { > + /* gpu_i2c_read has implicit stop */ Did reads not also have an implicit start? You could mention that explicitly as well. > + status = gpu_i2c_read(i2cd, msgs[i].buf, msgs[i].len); > + if (status < 0) > + goto unlock; > + i2cd->do_start = true; > + } else { And here the problem with the preserved do_start state shows. If the first message is a write and do_start happens to be false here, which can happen if a previous write failed in the middle, there will be no start before the write (and the address is not going to be transferred either). > + if (i2cd->do_start) { > + status = gpu_i2c_start(i2cd, msgs[i].addr); Why do you need to feed the address to a function that seems to only generate a start condition? I mean, the next thing that happens is that the address is written explicitly, so why does the hardware need the address before that write happens? This bit seems a bit crazy... > + if (status < 0) > + goto unlock; > + status = gpu_i2c_write(i2cd, msgs[i].addr << 1); You could use i2c_8bit_addr_from_msg(&msgs[i]) here instead of the "magic" shift, if you like. > + if (status < 0) > + goto stop; > + i2cd->do_start = false; > + } > + for (j = 0; j < msgs[i].len; j++) { > + status = gpu_i2c_write(i2cd, msgs[i].buf[j]); > + if (status < 0) > + goto stop; > + } > + /* stop if last write message */ > + if (i == (num - 1)) { > + status = gpu_i2c_stop(i2cd); > + if (status < 0) > + goto unlock; > + i2cd->do_start = true; > + } > + } > + } > + status = i; > + goto unlock; > +stop: > + status = gpu_i2c_stop(i2cd); > +unlock: > + mutex_unlock(&i2cd->mutex); > + return status; > +} > + > +static const struct i2c_adapter_quirks gpu_i2c_quirks = { > + .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | I2C_AQ_COMB_SAME_ADDR, > + .max_read_len = 4, > +}; > + > +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) > +{ > + static struct i2c_board_info gpu_ccgx_ucsi = { > + I2C_BOARD_INFO("ccgx-ucsi", 0x8), > + }; > + > + gpu_ccgx_ucsi.irq = irq; > + i2cd->client = i2c_new_device(&i2cd->adapter, &gpu_ccgx_ucsi); > + if (!i2cd->client) { > + dev_err(i2cd->dev, "i2c_new_device failed\n"); > + 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(struct gpu_i2c_dev), 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; > + } > + > + i2cd->do_start = true; > + mutex_init(&i2cd->mutex); > + 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) { > + dev_err(&pdev->dev, "i2c_add_adapter failed %d\n", status); I think i2c_add_adapter already barfs in the log on failure. And with more details too. Cheers, Peter > + 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 int gpu_i2c_idle(struct device *dev) > +{ > + struct gpu_i2c_dev *i2cd = dev_get_drvdata(dev); > + > + if (!mutex_trylock(&i2cd->mutex)) { > + dev_info(dev, "-EBUSY\n"); > + return -EBUSY; > + } > + mutex_unlock(&i2cd->mutex); > + > + return 0; > +} > + > +UNIVERSAL_DEV_PM_OPS(gpu_i2c_driver_pm, NULL, gpu_i2c_resume, gpu_i2c_idle); > + > +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"); >
Hi Peter, > > Latest NVIDIA GPU card has USB Type-C interface. There is a Type-C > > controller which can be accessed over I2C. > > > > This driver adds I2C bus driver to communicate with Type-C controller. > > I2C client driver will be part of USB Type-C UCSI driver. > > > > Signed-off-by: Ajay Gupta <ajayg@nvidia.com> > > Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> > > Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> > > --- > > Changes from v1 -> v2 > > None > > Changes from v2 -> v3 > > Fixed review comments from Andy and Thierry > > Rename i2c-gpu.c -> i2c-nvidia-gpu.c > > Changes from v3 -> v4 > > Fixed review comments from Andy > > Changes from v4 -> v5 > > Fixed review comments from Andy > > Changes from v5 -> v6 > > None > > Changes from v6 -> v7 -> v8 > > Fixed review comments from Peter > > - Add implicit STOP for last write message > > - Add i2c_adapter_quirks with max_read_len and > > I2C_AQ_COMB flags > > > > Documentation/i2c/busses/i2c-nvidia-gpu | 18 ++ > > MAINTAINERS | 7 + > > drivers/i2c/busses/Kconfig | 9 + > > drivers/i2c/busses/Makefile | 1 + > > drivers/i2c/busses/i2c-nvidia-gpu.c | 400 > ++++++++++++++++++++++++++++++++ > > 5 files changed, 435 insertions(+) > > create mode 100644 Documentation/i2c/busses/i2c-nvidia-gpu > > create mode 100644 drivers/i2c/busses/i2c-nvidia-gpu.c > > > > diff --git a/Documentation/i2c/busses/i2c-nvidia-gpu > > b/Documentation/i2c/busses/i2c-nvidia-gpu > > new file mode 100644 > > index 0000000..31884d2 > > --- /dev/null > > +++ b/Documentation/i2c/busses/i2c-nvidia-gpu > > @@ -0,0 +1,18 @@ > > +Kernel driver i2c-nvidia-gpu > > + > > +Datasheet: not publicly available. > > + > > +Authors: > > + Ajay Gupta <ajayg@nvidia.com> > > + > > +Description > > +----------- > > + > > +i2c-nvidia-gpu is a driver for I2C controller included in NVIDIA > > +Turing and later GPUs and it is used to communicate with Type-C controller > on GPUs. > > + > > +If your 'lspci -v' listing shows something like the following, > > + > > +01:00.3 Serial bus controller [0c80]: NVIDIA Corporation Device 1ad9 > > +(rev a1) > > + > > +then this driver should support the I2C controller of your GPU. > > diff --git a/MAINTAINERS b/MAINTAINERS index 9ad052a..2d1c5a1 100644 > > --- a/MAINTAINERS > > +++ b/MAINTAINERS > > @@ -6797,6 +6797,13 @@ L: linux-acpi@vger.kernel.org > > S: Maintained > > F: drivers/i2c/i2c-core-acpi.c > > > > +I2C CONTROLLER DRIVER FOR NVIDIA GPU > > +M: Ajay Gupta <ajayg@nvidia.com> > > +L: linux-i2c@vger.kernel.org > > +S: Maintained > > +F: Documentation/i2c/busses/i2c-nvidia-gpu > > +F: drivers/i2c/busses/i2c-nvidia-gpu.c > > + > > I2C MUXES > > M: Peter Rosin <peda@axentia.se> > > L: linux-i2c@vger.kernel.org > > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig > > index 451d4ae..eed827b 100644 > > --- a/drivers/i2c/busses/Kconfig > > +++ b/drivers/i2c/busses/Kconfig > > @@ -224,6 +224,15 @@ config I2C_NFORCE2_S4985 > > This driver can also be built as a module. If so, the module > > will be called i2c-nforce2-s4985. > > > > +config I2C_NVIDIA_GPU > > + tristate "NVIDIA GPU I2C controller" > > + depends on PCI > > + help > > + If you say yes to this option, support will be included for the > > + NVIDIA GPU I2C controller which is used to communicate with the > GPU's > > + Type-C controller. This driver can also be built as a module called > > + i2c-nvidia-gpu. > > + > > config I2C_SIS5595 > > tristate "SiS 5595" > > depends on PCI > > diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile > > index 18b26af..d499813 100644 > > --- a/drivers/i2c/busses/Makefile > > +++ b/drivers/i2c/busses/Makefile > > @@ -140,5 +140,6 @@ obj-$(CONFIG_I2C_SIBYTE) += i2c-sibyte.o > > obj-$(CONFIG_I2C_XGENE_SLIMPRO) += i2c-xgene-slimpro.o > > obj-$(CONFIG_SCx200_ACB) += scx200_acb.o > > obj-$(CONFIG_I2C_FSI) += i2c-fsi.o > > +obj-$(CONFIG_I2C_NVIDIA_GPU) += i2c-nvidia-gpu.o > > > > ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG diff --git > > a/drivers/i2c/busses/i2c-nvidia-gpu.c > > b/drivers/i2c/busses/i2c-nvidia-gpu.c > > new file mode 100644 > > index 0000000..4816a31 > > --- /dev/null > > +++ b/drivers/i2c/busses/i2c-nvidia-gpu.c > > @@ -0,0 +1,400 @@ > > +// 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/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_NONE (0 << 2) > > +#define I2C_MST_CNTL_CMD_READ (1 << 2) > > +#define I2C_MST_CNTL_CMD_WRITE (2 << 2) > > +#define I2C_MST_CNTL_GEN_RAB BIT(4) > > +#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_ADDR_DAB 0 > > + > > +#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_client *client; > > + struct mutex mutex; /* to sync read/write */ > > + bool do_start; > > I don't think do_start belongs here. master_xfer should always start with a > start, either explicit if the first message is a write or implicit if it's a read. The > is no value in keeping this state between different calls to master_xfer. It's > actually error-prone, see below. I think do_start is not needed and so will drop it. > > +}; > > + > > +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(1000, 2000); > > + } while (time_is_after_jiffies(target)); > > + if (time_is_before_jiffies(target)) { > > + dev_err(i2cd->dev, "i2c timeout error %x\n", val); > > + return -EIO; > > + } > > + > > + 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 -EIO; > > + case I2C_MST_CNTL_STATUS_TIMEOUT: > > + return -ETIME; > > + case I2C_MST_CNTL_STATUS_BUS_BUSY: > > + return -EBUSY; > > + 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_GEN_STOP | > > + I2C_MST_CNTL_CMD_READ | (len << > I2C_MST_CNTL_BURST_SIZE_SHIFT) | > > + I2C_MST_CNTL_CYCLE_TRIGGER | > I2C_MST_CNTL_GEN_NACK; > > + val &= ~I2C_MST_CNTL_GEN_RAB; > > + 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, u16 addr) { > > + u32 val; > > + > > + val = addr << I2C_MST_ADDR_DAB; > > + writel(val, i2cd->regs + I2C_MST_ADDR); > > + > > + val = I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_CMD_NONE | > > + I2C_MST_CNTL_GEN_NACK; > > + val &= ~(I2C_MST_CNTL_GEN_STOP | I2C_MST_CNTL_GEN_RAB); > > + writel(val, i2cd->regs + I2C_MST_CNTL); > > + > > + return gpu_i2c_check_status(i2cd); > > +} > > + > > +static int gpu_i2c_stop(struct gpu_i2c_dev *i2cd) { > > + u32 val; > > + > > + val = I2C_MST_CNTL_GEN_STOP | I2C_MST_CNTL_CMD_NONE | > > + I2C_MST_CNTL_GEN_NACK; > > + val &= ~(I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_GEN_RAB); > > + writel(val, 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) | > > + I2C_MST_CNTL_GEN_NACK; > > + val &= ~(I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_GEN_STOP | > > + I2C_MST_CNTL_GEN_RAB); > > + 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; > > + int i, j; > > + > > + mutex_lock(&i2cd->mutex); > > + for (i = 0; i < num; i++) { > > + if (msgs[i].flags & I2C_M_RD) { > > + /* gpu_i2c_read has implicit stop */ > > Did reads not also have an implicit start? You could mention that explicitly as > well. ok > > > + status = gpu_i2c_read(i2cd, msgs[i].buf, msgs[i].len); > > + if (status < 0) > > + goto unlock; > > + i2cd->do_start = true; > > + } else { > > And here the problem with the preserved do_start state shows. If the first > message is a write and do_start happens to be false here, which can happen if > a previous write failed in the middle, there will be no start before the write > (and the address is not going to be transferred either). Ok, will drop do_start. > > > + if (i2cd->do_start) { > > + status = gpu_i2c_start(i2cd, msgs[i].addr); > > Why do you need to feed the address to a function that seems to only > generate a start condition? Current client address needs to be programmed in I2C_MST_ADDR register. This has to be programmed once for each client before starting any transfer. > I mean, the next thing that happens is that the > address is written explicitly, so why does the hardware need the address > before that write happens? This bit seems a bit crazy... This time the address goes as DATA on i2c bus. > > + if (status < 0) > > + goto unlock; > > + status = gpu_i2c_write(i2cd, msgs[i].addr << > 1); > > You could use i2c_8bit_addr_from_msg(&msgs[i]) here instead of the "magic" > shift, if you like. Ok, will use it. > > > + if (status < 0) > > + goto stop; > > + i2cd->do_start = false; > > + } > > + for (j = 0; j < msgs[i].len; j++) { > > + status = gpu_i2c_write(i2cd, msgs[i].buf[j]); > > + if (status < 0) > > + goto stop; > > + } > > + /* stop if last write message */ > > + if (i == (num - 1)) { > > + status = gpu_i2c_stop(i2cd); > > + if (status < 0) > > + goto unlock; > > + i2cd->do_start = true; > > + } > > + } > > + } > > + status = i; > > + goto unlock; > > +stop: > > + status = gpu_i2c_stop(i2cd); > > +unlock: > > + mutex_unlock(&i2cd->mutex); > > + return status; > > +} > > + > > +static const struct i2c_adapter_quirks gpu_i2c_quirks = { > > + .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | > I2C_AQ_COMB_SAME_ADDR, > > + .max_read_len = 4, > > +}; > > + > > +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) { > > + static struct i2c_board_info gpu_ccgx_ucsi = { > > + I2C_BOARD_INFO("ccgx-ucsi", 0x8), > > + }; > > + > > + gpu_ccgx_ucsi.irq = irq; > > + i2cd->client = i2c_new_device(&i2cd->adapter, &gpu_ccgx_ucsi); > > + if (!i2cd->client) { > > + dev_err(i2cd->dev, "i2c_new_device failed\n"); > > + 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(struct gpu_i2c_dev), > 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; > > + } > > + > > + i2cd->do_start = true; > > + mutex_init(&i2cd->mutex); > > + 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) { > > + dev_err(&pdev->dev, "i2c_add_adapter failed %d\n", status); > > I think i2c_add_adapter already barfs in the log on failure. And with more > details too. Ok, will drop. Thanks Ajay -- nvpublic -- > > Cheers, > Peter > > > + 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 int gpu_i2c_idle(struct device *dev) { > > + struct gpu_i2c_dev *i2cd = dev_get_drvdata(dev); > > + > > + if (!mutex_trylock(&i2cd->mutex)) { > > + dev_info(dev, "-EBUSY\n"); > > + return -EBUSY; > > + } > > + mutex_unlock(&i2cd->mutex); > > + > > + return 0; > > +} > > + > > +UNIVERSAL_DEV_PM_OPS(gpu_i2c_driver_pm, NULL, gpu_i2c_resume, > > +gpu_i2c_idle); > > + > > +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"); > >
diff --git a/Documentation/i2c/busses/i2c-nvidia-gpu b/Documentation/i2c/busses/i2c-nvidia-gpu new file mode 100644 index 0000000..31884d2 --- /dev/null +++ b/Documentation/i2c/busses/i2c-nvidia-gpu @@ -0,0 +1,18 @@ +Kernel driver i2c-nvidia-gpu + +Datasheet: not publicly available. + +Authors: + Ajay Gupta <ajayg@nvidia.com> + +Description +----------- + +i2c-nvidia-gpu is a driver for I2C controller included in NVIDIA Turing +and later GPUs and it is used to communicate with Type-C controller on GPUs. + +If your 'lspci -v' listing shows something like the following, + +01:00.3 Serial bus controller [0c80]: NVIDIA Corporation Device 1ad9 (rev a1) + +then this driver should support the I2C controller of your GPU. diff --git a/MAINTAINERS b/MAINTAINERS index 9ad052a..2d1c5a1 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6797,6 +6797,13 @@ L: linux-acpi@vger.kernel.org S: Maintained F: drivers/i2c/i2c-core-acpi.c +I2C CONTROLLER DRIVER FOR NVIDIA GPU +M: Ajay Gupta <ajayg@nvidia.com> +L: linux-i2c@vger.kernel.org +S: Maintained +F: Documentation/i2c/busses/i2c-nvidia-gpu +F: drivers/i2c/busses/i2c-nvidia-gpu.c + I2C MUXES M: Peter Rosin <peda@axentia.se> L: linux-i2c@vger.kernel.org diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 451d4ae..eed827b 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -224,6 +224,15 @@ config I2C_NFORCE2_S4985 This driver can also be built as a module. If so, the module will be called i2c-nforce2-s4985. +config I2C_NVIDIA_GPU + tristate "NVIDIA GPU I2C controller" + depends on PCI + help + If you say yes to this option, support will be included for the + NVIDIA GPU I2C controller which is used to communicate with the GPU's + Type-C controller. This driver can also be built as a module called + i2c-nvidia-gpu. + config I2C_SIS5595 tristate "SiS 5595" depends on PCI diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 18b26af..d499813 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -140,5 +140,6 @@ obj-$(CONFIG_I2C_SIBYTE) += i2c-sibyte.o obj-$(CONFIG_I2C_XGENE_SLIMPRO) += i2c-xgene-slimpro.o obj-$(CONFIG_SCx200_ACB) += scx200_acb.o obj-$(CONFIG_I2C_FSI) += i2c-fsi.o +obj-$(CONFIG_I2C_NVIDIA_GPU) += i2c-nvidia-gpu.o ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG diff --git a/drivers/i2c/busses/i2c-nvidia-gpu.c b/drivers/i2c/busses/i2c-nvidia-gpu.c new file mode 100644 index 0000000..4816a31 --- /dev/null +++ b/drivers/i2c/busses/i2c-nvidia-gpu.c @@ -0,0 +1,400 @@ +// 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/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_NONE (0 << 2) +#define I2C_MST_CNTL_CMD_READ (1 << 2) +#define I2C_MST_CNTL_CMD_WRITE (2 << 2) +#define I2C_MST_CNTL_GEN_RAB BIT(4) +#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_ADDR_DAB 0 + +#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_client *client; + struct mutex mutex; /* to sync read/write */ + bool do_start; +}; + +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(1000, 2000); + } while (time_is_after_jiffies(target)); + if (time_is_before_jiffies(target)) { + dev_err(i2cd->dev, "i2c timeout error %x\n", val); + return -EIO; + } + + 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 -EIO; + case I2C_MST_CNTL_STATUS_TIMEOUT: + return -ETIME; + case I2C_MST_CNTL_STATUS_BUS_BUSY: + return -EBUSY; + 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_GEN_STOP | + I2C_MST_CNTL_CMD_READ | (len << I2C_MST_CNTL_BURST_SIZE_SHIFT) | + I2C_MST_CNTL_CYCLE_TRIGGER | I2C_MST_CNTL_GEN_NACK; + val &= ~I2C_MST_CNTL_GEN_RAB; + 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, u16 addr) +{ + u32 val; + + val = addr << I2C_MST_ADDR_DAB; + writel(val, i2cd->regs + I2C_MST_ADDR); + + val = I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_CMD_NONE | + I2C_MST_CNTL_GEN_NACK; + val &= ~(I2C_MST_CNTL_GEN_STOP | I2C_MST_CNTL_GEN_RAB); + writel(val, i2cd->regs + I2C_MST_CNTL); + + return gpu_i2c_check_status(i2cd); +} + +static int gpu_i2c_stop(struct gpu_i2c_dev *i2cd) +{ + u32 val; + + val = I2C_MST_CNTL_GEN_STOP | I2C_MST_CNTL_CMD_NONE | + I2C_MST_CNTL_GEN_NACK; + val &= ~(I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_GEN_RAB); + writel(val, 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) | + I2C_MST_CNTL_GEN_NACK; + val &= ~(I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_GEN_STOP | + I2C_MST_CNTL_GEN_RAB); + 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; + int i, j; + + mutex_lock(&i2cd->mutex); + for (i = 0; i < num; i++) { + if (msgs[i].flags & I2C_M_RD) { + /* gpu_i2c_read has implicit stop */ + status = gpu_i2c_read(i2cd, msgs[i].buf, msgs[i].len); + if (status < 0) + goto unlock; + i2cd->do_start = true; + } else { + if (i2cd->do_start) { + status = gpu_i2c_start(i2cd, msgs[i].addr); + if (status < 0) + goto unlock; + status = gpu_i2c_write(i2cd, msgs[i].addr << 1); + if (status < 0) + goto stop; + i2cd->do_start = false; + } + for (j = 0; j < msgs[i].len; j++) { + status = gpu_i2c_write(i2cd, msgs[i].buf[j]); + if (status < 0) + goto stop; + } + /* stop if last write message */ + if (i == (num - 1)) { + status = gpu_i2c_stop(i2cd); + if (status < 0) + goto unlock; + i2cd->do_start = true; + } + } + } + status = i; + goto unlock; +stop: + status = gpu_i2c_stop(i2cd); +unlock: + mutex_unlock(&i2cd->mutex); + return status; +} + +static const struct i2c_adapter_quirks gpu_i2c_quirks = { + .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | I2C_AQ_COMB_SAME_ADDR, + .max_read_len = 4, +}; + +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) +{ + static struct i2c_board_info gpu_ccgx_ucsi = { + I2C_BOARD_INFO("ccgx-ucsi", 0x8), + }; + + gpu_ccgx_ucsi.irq = irq; + i2cd->client = i2c_new_device(&i2cd->adapter, &gpu_ccgx_ucsi); + if (!i2cd->client) { + dev_err(i2cd->dev, "i2c_new_device failed\n"); + 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(struct gpu_i2c_dev), 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; + } + + i2cd->do_start = true; + mutex_init(&i2cd->mutex); + 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) { + dev_err(&pdev->dev, "i2c_add_adapter failed %d\n", status); + 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 int gpu_i2c_idle(struct device *dev) +{ + struct gpu_i2c_dev *i2cd = dev_get_drvdata(dev); + + if (!mutex_trylock(&i2cd->mutex)) { + dev_info(dev, "-EBUSY\n"); + return -EBUSY; + } + mutex_unlock(&i2cd->mutex); + + return 0; +} + +UNIVERSAL_DEV_PM_OPS(gpu_i2c_driver_pm, NULL, gpu_i2c_resume, gpu_i2c_idle); + +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");