Re: [PATCH v4] i2c: designware: Add driver support for AMD NAVI GPU

From: Andy Shevchenko
Date: Wed Mar 31 2021 - 10:20:28 EST

On Wed, Mar 31, 2021 at 07:37:30PM +0530, Sanket Goswami wrote:
> The Latest AMD NAVI GPU card has an integrated Type-C controller and
> Designware I2C with PCI Interface. The PD controller for USB Type-C can
> be accessed over I2C. The client driver is part of the USB Type-C UCSI
> driver.
>
> Also, there exists a couple of notable IP limitations that are dealt as
> workarounds:
> - I2C transaction work on a polling mode as IP does not generate
> interrupt.
> - I2C read command sent twice to address the IP issues.
> - AMD NAVI GPU based products are already in the commercial market,
> hence some of the I2C parameters are statically programmed as they
> can not be part of the ACPI table.

Looks good enough to me, thanks.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

> Reviewed-by: Shyam Sundar S K <Shyam-sundar.S-k@xxxxxxx>
> Co-developed-by: Nehal Bakulchandra Shah <Nehal-Bakulchandra.shah@xxxxxxx>
> Signed-off-by: Nehal Bakulchandra Shah <Nehal-Bakulchandra.shah@xxxxxxx>
> Signed-off-by: Sanket Goswami <Sanket.Goswami@xxxxxxx>
> ---
> Changes in v4:
> - Fixes review comments given by Andy.
>
> Changes in v3:
> - Fixes runtime PM issue.
> - Addressed review comments were given by Jarkko and Andy.
>
> Changes in v2:
> - Utilized existing functionality of i2c_dw_xfer_init to configure I2C
> bus.
> - Removed i2c_dw_populate_client and rewrrient navi_amd_register_client
> to deduplicate from existing drivers.
> - Addressed review comments were given by Andy.
>
> drivers/i2c/busses/i2c-designware-common.c | 3 +
> drivers/i2c/busses/i2c-designware-core.h | 8 ++
> drivers/i2c/busses/i2c-designware-master.c | 133 +++++++++++++++++++++
> drivers/i2c/busses/i2c-designware-pcidrv.c | 61 ++++++++++
> 4 files changed, 205 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c
> index 3c19aada4b30..fdc34d9e3702 100644
> --- a/drivers/i2c/busses/i2c-designware-common.c
> +++ b/drivers/i2c/busses/i2c-designware-common.c
> @@ -150,6 +150,9 @@ int i2c_dw_init_regmap(struct dw_i2c_dev *dev)
> reg = readl(dev->base + DW_IC_COMP_TYPE);
> i2c_dw_release_lock(dev);
>
> + if ((dev->flags & MODEL_MASK) == MODEL_AMD_NAVI_GPU)
> + map_cfg.max_register = AMD_UCSI_INTR_REG;
> +
> if (reg == swab32(DW_IC_COMP_TYPE_VALUE)) {
> map_cfg.reg_read = dw_reg_read_swab;
> map_cfg.reg_write = dw_reg_write_swab;
> diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
> index 5392b82f68a4..6a53f75abf7c 100644
> --- a/drivers/i2c/busses/i2c-designware-core.h
> +++ b/drivers/i2c/busses/i2c-designware-core.h
> @@ -295,8 +295,16 @@ struct dw_i2c_dev {
>
> #define MODEL_MSCC_OCELOT BIT(8)
> #define MODEL_BAIKAL_BT1 BIT(9)
> +#define MODEL_AMD_NAVI_GPU BIT(10)
> #define MODEL_MASK GENMASK(11, 8)
>
> +/*
> + * Enable UCSI interrupt by writing 0xd at register
> + * offset 0x474 specified in hardware specification.
> + */
> +#define AMD_UCSI_INTR_REG 0x474
> +#define AMD_UCSI_INTR_EN 0xd
> +
> int i2c_dw_init_regmap(struct dw_i2c_dev *dev);
> u32 i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset);
> u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset);
> diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
> index dd27b9dbe931..e288b654cb47 100644
> --- a/drivers/i2c/busses/i2c-designware-master.c
> +++ b/drivers/i2c/busses/i2c-designware-master.c
> @@ -23,6 +23,10 @@
>
> #include "i2c-designware-core.h"
>
> +#define AMD_TIMEOUT_MIN_US 25
> +#define AMD_TIMEOUT_MAX_US 250
> +#define AMD_MASTERCFG_MASK GENMASK(15, 0)
> +
> static void i2c_dw_configure_fifo_master(struct dw_i2c_dev *dev)
> {
> /* Configure Tx/Rx FIFO threshold levels */
> @@ -259,6 +263,108 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
> regmap_write(dev->map, DW_IC_INTR_MASK, DW_IC_INTR_MASTER_MASK);
> }
>
> +static int i2c_dw_check_stopbit(struct dw_i2c_dev *dev)
> +{
> + u32 val;
> + int ret;
> +
> + ret = regmap_read_poll_timeout(dev->map, DW_IC_INTR_STAT, val,
> + !(val & DW_IC_INTR_STOP_DET),
> + 1100, 20000);
> + if (ret)
> + dev_err(dev->dev, "i2c timeout error %d\n", ret);
> +
> + return ret;
> +}
> +
> +static int i2c_dw_status(struct dw_i2c_dev *dev)
> +{
> + int status;
> +
> + status = i2c_dw_wait_bus_not_busy(dev);
> + if (status)
> + return status;
> +
> + return i2c_dw_check_stopbit(dev);
> +}
> +
> +/*
> + * Initiate and continue master read/write transaction with polling
> + * based transfer routine afterward write messages into the Tx buffer.
> + */
> +static int amd_i2c_dw_xfer_quirk(struct i2c_adapter *adap, struct i2c_msg *msgs, int num_msgs)
> +{
> + struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
> + int msg_wrt_idx, msg_itr_lmt, buf_len, data_idx;
> + int cmd = 0, status;
> + u8 *tx_buf;
> + u32 val;
> +
> + /*
> + * In order to enable the interrupt for UCSI i.e. AMD NAVI GPU card,
> + * it is mandatory to set the right value in specific register
> + * (offset:0x474) as per the hardware IP specification.
> + */
> + regmap_write(dev->map, AMD_UCSI_INTR_REG, AMD_UCSI_INTR_EN);
> +
> + dev->msgs = msgs;
> + dev->msgs_num = num_msgs;
> + i2c_dw_xfer_init(dev);
> + i2c_dw_disable_int(dev);
> +
> + /* Initiate messages read/write transaction */
> + for (msg_wrt_idx = 0; msg_wrt_idx < num_msgs; msg_wrt_idx++) {
> + tx_buf = msgs[msg_wrt_idx].buf;
> + buf_len = msgs[msg_wrt_idx].len;
> +
> + if (!(msgs[msg_wrt_idx].flags & I2C_M_RD))
> + regmap_write(dev->map, DW_IC_TX_TL, buf_len - 1);
> + /*
> + * Initiate the i2c read/write transaction of buffer length,
> + * and poll for bus busy status. For the last message transfer,
> + * update the command with stopbit enable.
> + */
> + for (msg_itr_lmt = buf_len; msg_itr_lmt > 0; msg_itr_lmt--) {
> + if (msg_wrt_idx == num_msgs - 1 && msg_itr_lmt == 1)
> + cmd |= BIT(9);
> +
> + if (msgs[msg_wrt_idx].flags & I2C_M_RD) {
> + /* Due to hardware bug, need to write the same command twice. */
> + regmap_write(dev->map, DW_IC_DATA_CMD, 0x100);
> + regmap_write(dev->map, DW_IC_DATA_CMD, 0x100 | cmd);
> + if (cmd) {
> + regmap_write(dev->map, DW_IC_TX_TL, 2 * (buf_len - 1));
> + regmap_write(dev->map, DW_IC_RX_TL, 2 * (buf_len - 1));
> + /*
> + * Need to check the stop bit. However, it cannot be
> + * detected from the registers so we check it always
> + * when read/write the last byte.
> + */
> + status = i2c_dw_status(dev);
> + if (status)
> + return status;
> +
> + for (data_idx = 0; data_idx < buf_len; data_idx++) {
> + regmap_read(dev->map, DW_IC_DATA_CMD, &val);
> + tx_buf[data_idx] = val;
> + }
> + status = i2c_dw_check_stopbit(dev);
> + if (status)
> + return status;
> + }
> + } else {
> + regmap_write(dev->map, DW_IC_DATA_CMD, *tx_buf++ | cmd);
> + usleep_range(AMD_TIMEOUT_MIN_US, AMD_TIMEOUT_MAX_US);
> + }
> + }
> + status = i2c_dw_check_stopbit(dev);
> + if (status)
> + return status;
> + }
> +
> + return 0;
> +}
> +
> /*
> * Initiate (and continue) low level master read/write transaction.
> * This function is only called from i2c_dw_isr, and pumping i2c_msg
> @@ -462,6 +568,16 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
>
> pm_runtime_get_sync(dev->dev);
>
> + /*
> + * Initiate I2C message transfer when AMD NAVI GPU card is enabled,
> + * As it is polling based transfer mechanism, which does not support
> + * interrupt based functionalities of existing DesignWare driver.
> + */
> + if ((dev->flags & MODEL_MASK) == MODEL_AMD_NAVI_GPU) {
> + ret = amd_i2c_dw_xfer_quirk(adap, msgs, num);
> + goto done_nolock;
> + }
> +
> if (dev_WARN_ONCE(dev->dev, dev->suspended, "Transfer while suspended\n")) {
> ret = -ESHUTDOWN;
> goto done_nolock;
> @@ -738,6 +854,20 @@ static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
> return 0;
> }
>
> +static int amd_i2c_adap_quirk(struct dw_i2c_dev *dev)
> +{
> + struct i2c_adapter *adap = &dev->adapter;
> + int ret;
> +
> + pm_runtime_get_noresume(dev->dev);
> + ret = i2c_add_numbered_adapter(adap);
> + if (ret)
> + dev_err(dev->dev, "Failed to add adapter: %d\n", ret);
> + pm_runtime_put_noidle(dev->dev);
> +
> + return ret;
> +}
> +
> int i2c_dw_probe_master(struct dw_i2c_dev *dev)
> {
> struct i2c_adapter *adap = &dev->adapter;
> @@ -774,6 +904,9 @@ int i2c_dw_probe_master(struct dw_i2c_dev *dev)
> adap->dev.parent = dev->dev;
> i2c_set_adapdata(adap, dev);
>
> + if ((dev->flags & MODEL_MASK) == MODEL_AMD_NAVI_GPU)
> + return amd_i2c_adap_quirk(dev);
> +
> if (dev->flags & ACCESS_NO_IRQ_SUSPEND) {
> irq_flags = IRQF_NO_SUSPEND;
> } else {
> diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c b/drivers/i2c/busses/i2c-designware-pcidrv.c
> index 55c83a7a24f3..7ca0017883a6 100644
> --- a/drivers/i2c/busses/i2c-designware-pcidrv.c
> +++ b/drivers/i2c/busses/i2c-designware-pcidrv.c
> @@ -26,6 +26,7 @@
> #include "i2c-designware-core.h"
>
> #define DRIVER_NAME "i2c-designware-pci"
> +#define AMD_CLK_RATE_HZ 100000
>
> enum dw_pci_ctl_id_t {
> medfield,
> @@ -34,6 +35,7 @@ enum dw_pci_ctl_id_t {
> cherrytrail,
> haswell,
> elkhartlake,
> + navi_amd,
> };
>
> struct dw_scl_sda_cfg {
> @@ -78,11 +80,23 @@ static struct dw_scl_sda_cfg hsw_config = {
> .sda_hold = 0x9,
> };
>
> +/* NAVI-AMD HCNT/LCNT/SDA hold time */
> +static struct dw_scl_sda_cfg navi_amd_config = {
> + .ss_hcnt = 0x1ae,
> + .ss_lcnt = 0x23a,
> + .sda_hold = 0x9,
> +};
> +
> static u32 mfld_get_clk_rate_khz(struct dw_i2c_dev *dev)
> {
> return 25000;
> }
>
> +static u32 navi_amd_get_clk_rate_khz(struct dw_i2c_dev *dev)
> +{
> + return AMD_CLK_RATE_HZ;
> +}
> +
> static int mfld_setup(struct pci_dev *pdev, struct dw_pci_controller *c)
> {
> struct dw_i2c_dev *dev = dev_get_drvdata(&pdev->dev);
> @@ -104,6 +118,35 @@ static int mfld_setup(struct pci_dev *pdev, struct dw_pci_controller *c)
> return -ENODEV;
> }
>
> + /*
> + * TODO find a better way how to deduplicate instantiation
> + * of USB PD slave device from nVidia GPU driver.
> + */
> +static int navi_amd_register_client(struct dw_i2c_dev *dev)
> +{
> + struct i2c_board_info info;
> +
> + memset(&info, 0, sizeof(struct i2c_board_info));
> + strscpy(info.type, "ccgx-ucsi", I2C_NAME_SIZE);
> + info.addr = 0x08;
> + info.irq = dev->irq;
> +
> + dev->slave = i2c_new_client_device(&dev->adapter, &info);
> + if (!dev->slave)
> + return -ENODEV;
> +
> + return 0;
> +}
> +
> +static int navi_amd_setup(struct pci_dev *pdev, struct dw_pci_controller *c)
> +{
> + struct dw_i2c_dev *dev = dev_get_drvdata(&pdev->dev);
> +
> + dev->flags |= MODEL_AMD_NAVI_GPU;
> + dev->timings.bus_freq_hz = I2C_MAX_STANDARD_MODE_FREQ;
> + return 0;
> +}
> +
> static int mrfld_setup(struct pci_dev *pdev, struct dw_pci_controller *c)
> {
> /*
> @@ -155,6 +198,12 @@ static struct dw_pci_controller dw_pci_controllers[] = {
> .bus_num = -1,
> .get_clk_rate_khz = ehl_get_clk_rate_khz,
> },
> + [navi_amd] = {
> + .bus_num = -1,
> + .scl_sda_cfg = &navi_amd_config,
> + .setup = navi_amd_setup,
> + .get_clk_rate_khz = navi_amd_get_clk_rate_khz,
> + },
> };
>
> #ifdef CONFIG_PM
> @@ -274,6 +323,14 @@ static int i2c_dw_pci_probe(struct pci_dev *pdev,
> return r;
> }
>
> + if ((dev->flags & MODEL_MASK) == MODEL_AMD_NAVI_GPU) {
> + r = navi_amd_register_client(dev);
> + if (r) {
> + dev_err(dev->dev, "register client failed with %d\n", r);
> + return r;
> + }
> + }
> +
> pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
> pm_runtime_use_autosuspend(&pdev->dev);
> pm_runtime_put_autosuspend(&pdev->dev);
> @@ -337,6 +394,10 @@ static const struct pci_device_id i2_designware_pci_ids[] = {
> { PCI_VDEVICE(INTEL, 0x4bbe), elkhartlake },
> { PCI_VDEVICE(INTEL, 0x4bbf), elkhartlake },
> { PCI_VDEVICE(INTEL, 0x4bc0), elkhartlake },
> + { PCI_VDEVICE(ATI, 0x7314), navi_amd },
> + { PCI_VDEVICE(ATI, 0x73a4), navi_amd },
> + { PCI_VDEVICE(ATI, 0x73e4), navi_amd },
> + { PCI_VDEVICE(ATI, 0x73c4), navi_amd },
> { 0,}
> };
> MODULE_DEVICE_TABLE(pci, i2_designware_pci_ids);
> --
> 2.25.1
>

--
With Best Regards,
Andy Shevchenko