Hi Peter, > > 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@xxxxxxxxxx> > > Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> > > Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> > > --- > > 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 > > Changes from v8 -> v9 > > Fixed review comments from Peter > > - Drop do_start flag > > - Use i2c_8bit_addr_from_msg() > > Changes from v9 -> v10 > > Fixed review comments from Peter > > - Dropped I2C_FUNC_SMBUS_EMUL > > - Dropped local mutex > > Changes from v10 -> v11 > > Fixed review comments from Peter > > - Moved stop in master_xfer at end of message > > - Change i2c_read without STOP > > - Dropped I2C_AC_COMB* flags > > Changes from v11 -> v12 > > Fixed review comments from Peter > > - Removed clearing of empty bits > > - Fix master_xfer for correct stop use > > > > 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 | 368 > ++++++++++++++++++++++++++++++++ > > 5 files changed, 403 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 d870cb5..b71b0b4 100644 > > --- a/MAINTAINERS > > +++ b/MAINTAINERS > > @@ -6798,6 +6798,13 @@ 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..0c16b0a > > --- /dev/null > > +++ b/drivers/i2c/busses/i2c-nvidia-gpu.c > > @@ -0,0 +1,368 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * Nvidia GPU I2C controller Driver > > + * > > + * Copyright (C) 2018 NVIDIA Corporation. All rights reserved. > > + * Author: Ajay Gupta <ajayg@xxxxxxxxxx> */ #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_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)) > > It occurred to me that generating NACK only makes sense for reads, and that > you only want to have a NACK after the final byte in a read messages. So, > here's a new attempt. > > What if you replace the above test with > > if (!(val & I2C_MST_CNTL_READ)) > > (since all cycle-triggers are also reads, at least currently, and we also want to > wait for the tail reads to complete before we try to get the received data from > the register) > > and then... > > > + 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 -ETIME; > > + } > > + > > + 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_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; > > +} > > ...replace your gpu_i2c_read with this: > > #define GPU_MAX_BURST 1 > static int gpu_i2c_read(struct gpu_i2c_dev *i2cd, u8 *data, u16 len) { > u16 burst = min(len, GPU_MAX_BURST); > int status; > u32 val; > > val = I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_CMD_READ | > (burst << I2C_MST_CNTL_BURST_SIZE_SHIFT) | > I2C_MST_CNTL_CYCLE_TRIGGER; > > for (;;) { > if (len <= GPU_MAX_BURST) > val |= 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 (burst) { > 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; > } > > if (len <= GPU_MAX_BURST) > break; > > data += GPU_MAX_BURST; > len -= GPU_MAX_BURST; > > burst = min(len, GPU_MAX_BURST); > val = I2C_MST_CNTL_CMD_READ | > (burst << I2C_MST_CNTL_BURST_SIZE_SHIFT); > } > > return status; > } > > If that works, > then change GPU_MAX_BURST to 4, drop the quirk and the > splitting of the reads in patch 2/2 and check that too... > > *fingers crossed* Unfortunately, that also didn't work. I tried some tweaks with _TRIGGER and _START but that also didn't help. > > + > > +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) | > > + I2C_MST_CNTL_GEN_NACK; > > Generating NACK for a write does not make sense, which is what I think the > last flag means? It's the client device that has the power to ACK/NACK writes. Ok, will check. > > + 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; > > + > > + 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) { > > + if (i == 0) > > + return status; > > I missed this in my first reply to this message. You want an unconditional > "goto stop" here, so please drop the "if (i == 0) return status;" thing. > My reasoning is that a spurious stop is - while undesirable - much better than > a missing stop. Ok. > > + 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, > > +}; > > + > > +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(struct i2c_board_info), > > I prefer sizeof(*i2cd->gpu_ccgx_ucsi). Especially when the type is far away as > it is here... First one looks more readable and cleaner to me but will change. sizeof(struct i2c_board_info), 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(struct gpu_i2c_dev), > > +GFP_KERNEL); > > While at it, you might as well change this to sizeof(*i2cd), and Ok. > please check for the pattern in patch 2/2. I hope you saw the latest response at [1]. The change works on multiple systems and no error has been reported yet. What else (and how) to check ? [1] https://marc.info/?l=linux-usb&m=153667127502959&w=2 Thanks Ajay --nvpublic > > Cheers, > Peter > > > + 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; > > +} > > + > > +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 <ajayg@xxxxxxxxxx>"); > > +MODULE_DESCRIPTION("Nvidia GPU I2C controller Driver"); > > +MODULE_LICENSE("GPL v2"); > >