On Thu, Aug 30, 2018 at 3:35 AM <ajaykuee@xxxxxxxxx> wrote:
>
> From: Ajay Gupta <ajayg@xxxxxxxxxx>
>
> 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.
>
Some small comments below, after addressing them
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> Signed-off-by: Ajay Gupta <ajayg@xxxxxxxxxx>
> ---
> Changes from v1 -> v2
> None
> Changes from v2 -> v3
> Fixed review comments from Andy and Thierry
> Rename i2c-gpu.c -> i2c-nvidia-gpu.c
>
> 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 | 389 ++++++++++++++++++++++++++++++++
> 5 files changed, 424 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@xxxxxxxxxx>
> +
> +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@xxxxxxxxxxxxxxx
> S: Maintained
> F: drivers/i2c/i2c-core-acpi.c
>
> +I2C CONTROLLER DRIVER FOR NVIDIA GPU
> +M: Ajay Gupta <ajayg@xxxxxxxxxx>
> +L: linux-i2c@xxxxxxxxxxxxxxx
> +S: Maintained
> +F: Documentation/i2c/busses/i2c-nvidia-gpu
> +F: drivers/i2c/busses/i2c-nvidia-gpu.c
> +
> I2C MUXES
> M: Peter Rosin <peda@xxxxxxxxxx>
> L: linux-i2c@xxxxxxxxxxxxxxx
> 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..fa01187
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-nvidia-gpu.c
> @@ -0,0 +1,389 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Nvidia GPU I2C controller Driver
> + *
> + * Copyright (C) 2018 NVIDIA Corporation. All rights reserved.
> + * Author: Ajay Gupta <ajayg@xxxxxxxxxx>
> + *
Redundant line.
> + */
> +#include <asm/unaligned.h>
This should go after linux/* ones...
> +#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>
> +
...here.
> +/* I2C definitions */
> +#define I2C_MST_CNTL 0x0
> +#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)
Redundant parens
> +#define I2C_MST_CNTL_GEN_NACK BIT(28)
> +#define I2C_MST_CNTL_STATUS (3 << 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 pci_dev *pci_dev;
This should be a good argument why you are keeping struct pci_dev
instead of struct device.
> + void __iomem *regs;
> + struct i2c_adapter adapter;
> + struct i2c_client *client;
> + struct mutex mutex; /* to sync read/write */
> + bool do_start;
> +};
> +
> +static void 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 i2c_check_status(struct gpu_i2c_dev *i2cd)
> +{
> + unsigned long target = jiffies + msecs_to_jiffies(1000);
> + int status = -EIO;
You can get rid of this variable by returning in place.
> + u32 val;
> +
> + do {
> + val = readl(i2cd->regs + I2C_MST_CNTL);
> + if ((val & I2C_MST_CNTL_CYCLE_TRIGGER) !=
> + 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))
> + return status;
> +
> + val = readl(i2cd->regs + I2C_MST_CNTL);
> + switch (val & I2C_MST_CNTL_STATUS) {
> + case I2C_MST_CNTL_STATUS_OKAY:
> + status = 0;
> + break;
> + case I2C_MST_CNTL_STATUS_NO_ACK:
> + status = -EIO;
> + break;
> + case I2C_MST_CNTL_STATUS_TIMEOUT:
> + status = -ETIME;
> + break;
> + case I2C_MST_CNTL_STATUS_BUS_BUSY:
> + status = -EBUSY;
> + break;
> + default:
> + break;
> + }
> + return status;
> +}
> +
> +static int i2c_read(struct gpu_i2c_dev *i2cd, u8 *data, u16 len)
> +{
> + int status;
> + u32 val = 0;
> +
> + 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 = 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 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 i2c_check_status(i2cd);
> +}
> +
> +static int 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 i2c_check_status(i2cd);
> +}
> +
> +static int 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 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);
> + struct device *dev = &i2cd->pci_dev->dev;
> + int sts;
Btw, be consistent with names, status looks slightly better.
> + int i, j;
> +
> + mutex_lock(&i2cd->mutex);
> + for (i = 0; i < num; i++) {
> + if (msgs[i].flags & I2C_M_RD) {
> + sts = i2c_read(i2cd, msgs[i].buf, msgs[i].len);
> + if (sts < 0) {
> + dev_err(dev, "i2c_read error %x", sts);
> + break;
> + }
> + i2cd->do_start = true;
> + } else if (msgs[i].flags & I2C_M_STOP) {
> + sts = i2c_stop(i2cd);
> + if (sts < 0) {
> + dev_err(dev, "i2c_stop error %x", sts);
> + goto unlock;
> + }
> + i2cd->do_start = true;
> + } else {
> + if (i2cd->do_start) {
> + sts = i2c_start(i2cd, msgs[i].addr);
> + if (sts < 0) {
> + dev_err(dev, "i2c_start error %x", sts);
> + goto unlock;
> + }
> + sts = i2c_write(i2cd, msgs[i].addr << 1);
> + if (sts < 0) {
> + dev_err(dev, "i2c_write error %x", sts);
> + goto stop;
> + }
> + i2cd->do_start = false;
> + }
> + for (j = 0; j < msgs[i].len; j++) {
> + sts = i2c_write(i2cd, *(msgs[i].buf + j));
> + if (sts < 0) {
> + dev_err(dev, "i2c_write error %x", sts);
> + goto stop;
> + }
> + }
> + }
> + }
> + goto unlock;
> +stop:
> + sts = i2c_stop(i2cd);
> + if (sts < 0)
> + dev_err(dev, "i2c_stop error %x", sts);
> +unlock:
> + mutex_unlock(&i2cd->mutex);
> + return i;
> +}
> +
> +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,
> +};
> +
> +#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},
> + { }
> +};
I'm really in doubt how it's supposed to be enumerated without
conflicts or shadowing other hardware.
Explain in the comments, please.
> +MODULE_DEVICE_TABLE(pci, gpu_i2c_ids);
> +
> +static int gpu_i2c_probe(struct pci_dev *dev, const struct pci_device_id *id)
> +{
> + struct i2c_board_info gpu_i2c_ucsi_board_info = {
> + I2C_BOARD_INFO("ccgx-ucsi", 0x8)
> + };
Can't you rather put this as static const which is provided in
driver_data above (based on enumeration) and use here something like
static const struct i2c_board_info gpu_ccgx_ucsi = {
I2C_BOARD_INFO(...)
};
...
{ PCI_VENDOR_..., (kernel_ulong_t)&gpu_ccgx_ucsi }
...
?
Though it's up to you. More important is to split this part to a
separate function, like
static int gpu_populate_client(struct gpu_i2c_dev *i2cd, ...)
{
...
}
...
status = gpu_populate_client(...);
if (status) {
...
}
> + struct gpu_i2c_dev *i2cd;
> + int status;
> +
> + i2cd = devm_kzalloc(&dev->dev, sizeof(struct gpu_i2c_dev), GFP_KERNEL);
> + if (!i2cd)
> + return -ENOMEM;
> +
> + i2cd->pci_dev = dev;
> + pci_set_drvdata(dev, i2cd);
> +
> + status = pcim_enable_device(dev);
> + if (status < 0) {
> + dev_err(&dev->dev, "pcim_enable_device failed - %d\n", status);
> + return status;
> + }
> +
> + pci_set_master(dev);
> +
> + i2cd->regs = pcim_iomap(dev, 0, 0);
> + if (!i2cd->regs) {
> + dev_err(&dev->dev, "pcim_iomap failed\n");
> + return -ENOMEM;
> + }
> +
> + status = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_MSI);
> + if (status < 0) {
> + dev_err(&dev->dev, "pci_alloc_irq_vectors err - %d\n", status);
> + return status;
> + }
> +
> + i2cd->do_start = true;
> + mutex_init(&i2cd->mutex);
> + 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.dev.parent = &dev->dev;
> + status = i2c_add_adapter(&i2cd->adapter);
> + if (status < 0) {
> + dev_err(&dev->dev, "i2c_add_adapter failed - %d\n", status);
> + goto del_adapter;
> + }
> +
> + gpu_i2c_ucsi_board_info.irq = dev->irq;
> + i2cd->client = i2c_new_device(&i2cd->adapter, &gpu_i2c_ucsi_board_info);
> +
> + if (!i2cd->client) {
> + dev_err(&dev->dev, "i2c_new_device failed - %d\n", status);
> + status = -ENODEV;
> + goto del_adapter;
> + }
> +
> + pm_runtime_put_noidle(&dev->dev);
> + pm_runtime_allow(&dev->dev);
> +
> + return 0;
> +
> +del_adapter:
> + i2c_del_adapter(&i2cd->adapter);
> + pci_free_irq_vectors(dev);
> + return status;
> +}
> +
> +static void gpu_i2c_remove(struct pci_dev *dev)
> +{
> + struct gpu_i2c_dev *i2cd = pci_get_drvdata(dev);
> +
> + i2c_del_adapter(&i2cd->adapter);
> + pci_free_irq_vectors(dev);
> +}
> +
> +static int gpu_i2c_resume(struct device *dev)
> +{
> + struct gpu_i2c_dev *i2cd = pci_get_drvdata(to_pci_dev(dev));
> +
> + enable_i2c_bus(i2cd);
> + return 0;
> +}
> +
> +static int gpu_i2c_idle(struct device *dev)
> +{
> + struct gpu_i2c_dev *i2cd = pci_get_drvdata(to_pci_dev(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@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Nvidia GPU I2C controller Driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.7.4
>
--
With Best Regards,
Andy Shevchenko
