[PATCH] i2c: add i2c bus driver for amd navi gpu

From: Sanket Goswami
Date: Tue Mar 09 2021 - 08:34:41 EST

Latest AMDGPU NAVI cards have USB Type-C interface which can be accessed
over I2C. The Type-C controller has integrated designware i2c which is
exposed as a PCI device to the AMD platform.

Also there exists couple of notable IP problems that are dealt as a
workaround:
- I2C transactions work on a polling mode as IP does not generate
interrupt.

- I2C reads commands are sent twice to address the IP issues.

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>
---
drivers/i2c/busses/i2c-designware-common.c | 3 +
drivers/i2c/busses/i2c-designware-core.h | 3 +
drivers/i2c/busses/i2c-designware-master.c | 175 +++++++++++++++++++++
drivers/i2c/busses/i2c-designware-pcidrv.c | 56 +++++++
4 files changed, 237 insertions(+)

diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c
index 3c19aada4b30..50883a70b482 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 & AMD_NON_INTR_MODE)
+ 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 85307cfa7109..0cce4144b9ac 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -291,9 +291,12 @@ struct dw_i2c_dev {
#define ACCESS_INTR_MASK BIT(0)
#define ACCESS_NO_IRQ_SUSPEND BIT(1)

+#define AMD_NON_INTR_MODE BIT(2)
#define MODEL_MSCC_OCELOT BIT(8)
#define MODEL_BAIKAL_BT1 BIT(9)
#define MODEL_MASK GENMASK(11, 8)
+#define AMD_UCSI_INTR_EN 0xD
+#define AMD_UCSI_INTR_REG 0x474

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);
diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
index d6425ad6e6a3..35c894a01381 100644
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -22,6 +22,10 @@
#include <linux/reset.h>

#include "i2c-designware-core.h"
+#define AMD_TIMEOUT_MSEC_MIN 10000
+#define AMD_TIMEOUT_MSEC_MAX 11000
+#define AMD_FIFO_SIZE 0x20
+#define AMD_MASTERCFG_MASK GENMASK(15, 0)

static void i2c_dw_configure_fifo_master(struct dw_i2c_dev *dev)
{
@@ -33,6 +37,154 @@ static void i2c_dw_configure_fifo_master(struct dw_i2c_dev *dev)
regmap_write(dev->map, DW_IC_CON, dev->master_cfg);
}

+static void i2c_dw_configure_bus(struct dw_i2c_dev *i2cd)
+{
+ int master_cfg;
+ u16 icon;
+ u32 reg;
+
+ /* First disable the controller */
+ __i2c_dw_disable_nowait(i2cd);
+ master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE | DW_IC_CON_SPEED_STD;
+
+ /* Clear all the interrupts */
+ regmap_read(i2cd->map, DW_IC_CLR_INTR, &reg);
+ regmap_write(i2cd->map, DW_IC_INTR_MASK, STATUS_IDLE);
+
+ icon = master_cfg & AMD_MASTERCFG_MASK;
+ icon &= ~DW_IC_CON_10BITADDR_MASTER;
+ icon = icon | DW_IC_CON_SPEED_STD;
+
+ /* Configure the master */
+ regmap_write(i2cd->map, DW_IC_CON, icon);
+ /* Configure the FIFO */
+ regmap_write(i2cd->map, DW_IC_TX_TL, AMD_FIFO_SIZE);
+ regmap_write(i2cd->map, DW_IC_RX_TL, AMD_FIFO_SIZE);
+
+ /* Setup 100k Speed */
+ regmap_write(i2cd->map, DW_IC_SS_SCL_HCNT, i2cd->ss_hcnt);
+ regmap_write(i2cd->map, DW_IC_SS_SCL_LCNT, i2cd->ss_lcnt);
+ regmap_write(i2cd->map, DW_IC_TAR, 0x08);
+
+ /* Now enable the controller */
+ __i2c_dw_enable(i2cd);
+}
+
+static int i2c_dw_check_stopbit(struct dw_i2c_dev *i2cd)
+{
+ u32 val;
+ int ret;
+
+ ret = regmap_read_poll_timeout(i2cd->map, DW_IC_INTR_STAT, val,
+ !(val & DW_IC_INTR_STOP_DET),
+ 1100, 20000);
+ if (ret) {
+ dev_err(i2cd->dev, "i2c timeout error %d\n", ret);
+ return -ETIMEDOUT;
+ }
+
+ regmap_read(i2cd->map, DW_IC_CLR_INTR, &val);
+ if (val & DW_IC_INTR_STOP_DET)
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static int i2c_dw_status(struct dw_i2c_dev *i2cd)
+{
+ int status;
+
+ status = i2c_dw_wait_bus_not_busy(i2cd);
+ if (status)
+ return -ETIMEDOUT;
+
+ status = i2c_dw_check_stopbit(i2cd);
+ if (status)
+ return -ETIMEDOUT;
+
+ return status;
+}
+
+/* Initiate and continue master read/write transaction with polling
+ * based transfer routine and write messages into the tx buffer.
+ */
+static int amd_i2c_dw_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num_msgs)
+{
+ struct dw_i2c_dev *i2cd = i2c_get_adapdata(adap);
+ int msg_wrt_idx, msg_itr_lmt, buf_len, data_idx;
+ int cmd = 0, ret, status;
+ u8 *tx_buf;
+ u32 val;
+
+ ret = i2c_dw_acquire_lock(i2cd);
+ if (ret) {
+ dev_err(i2cd->dev, "Failed to get bus ownership\n");
+ return ret;
+ }
+
+ i2c_dw_configure_bus(i2cd);
+
+ /* 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(i2cd->map, DW_IC_TX_TL, buf_len - 1);
+
+ /* Initiate the i2c read/write transition 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 command two times. */
+ regmap_write(i2cd->map, DW_IC_DATA_CMD, 0x100);
+ regmap_write(i2cd->map, DW_IC_DATA_CMD, 0x100 | cmd);
+ if (cmd) {
+ regmap_write(i2cd->map, DW_IC_TX_TL, 2 * (buf_len - 1));
+ regmap_write(i2cd->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(i2cd);
+ if (status) {
+ ret = -ETIMEDOUT;
+ goto lock_release;
+ }
+ for (data_idx = 0; data_idx < buf_len; data_idx++) {
+ regmap_read(i2cd->map, DW_IC_DATA_CMD, &val);
+ tx_buf[data_idx] = val;
+ }
+ status = i2c_dw_check_stopbit(i2cd);
+ if (status) {
+ ret = -ETIMEDOUT;
+ goto lock_release;
+ }
+ }
+ } else {
+ regmap_write(i2cd->map, DW_IC_DATA_CMD, *tx_buf++ | cmd);
+ usleep_range(AMD_TIMEOUT_MSEC_MIN, AMD_TIMEOUT_MSEC_MAX);
+ }
+ }
+ status = i2c_dw_check_stopbit(i2cd);
+ if (status) {
+ ret = -ETIMEDOUT;
+ goto lock_release;
+ }
+ }
+
+lock_release:
+ i2c_dw_release_lock(i2cd);
+
+ return ret;
+}
+
static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
{
const char *mode_str, *fp_str = "";
@@ -208,6 +360,9 @@ static int i2c_dw_init_master(struct dw_i2c_dev *dev)
if (dev->sda_hold_time)
regmap_write(dev->map, DW_IC_SDA_HOLD, dev->sda_hold_time);

+ /* Enable ucsi interrupt */
+ if (dev->flags & AMD_NON_INTR_MODE)
+ regmap_write(dev->map, AMD_UCSI_INTR_REG, AMD_UCSI_INTR_EN);
i2c_dw_configure_fifo_master(dev);
i2c_dw_release_lock(dev);

@@ -462,6 +617,9 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)

pm_runtime_get_sync(dev->dev);

+ if (dev->flags & AMD_NON_INTR_MODE)
+ return amd_i2c_dw_master_xfer(adap, msgs, num);
+
if (dev_WARN_ONCE(dev->dev, dev->suspended, "Transfer while suspended\n")) {
ret = -ESHUTDOWN;
goto done_nolock;
@@ -738,6 +896,19 @@ static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
return 0;
}

+int amd_i2c_adap_quirk(struct dw_i2c_dev *amdev)
+{
+ struct i2c_adapter *amdap = &amdev->adapter;
+ int ret;
+
+ if (!(amdev->flags & AMD_NON_INTR_MODE))
+ return -ENODEV;
+
+ return i2c_add_numbered_adapter(amdap);
+
+ return ret;
+}
+
int i2c_dw_probe_master(struct dw_i2c_dev *dev)
{
struct i2c_adapter *adap = &dev->adapter;
@@ -774,6 +945,10 @@ int i2c_dw_probe_master(struct dw_i2c_dev *dev)
adap->dev.parent = dev->dev;
i2c_set_adapdata(adap, dev);

+ ret = amd_i2c_adap_quirk(dev);
+ if (ret != -ENODEV)
+ return ret;
+
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..69ea6f206ab2 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 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;
+}
+
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;
}

+static int i2c_dw_populate_client(struct dw_i2c_dev *i2cd)
+{
+ struct i2c_board_info *i2c_dw_ccgx_ucsi;
+ struct i2c_client *ccgx_client;
+
+ i2c_dw_ccgx_ucsi = devm_kzalloc(i2cd->dev, sizeof(*i2c_dw_ccgx_ucsi), GFP_KERNEL);
+ if (!i2c_dw_ccgx_ucsi)
+ return -ENOMEM;
+
+ strscpy(i2c_dw_ccgx_ucsi->type, "ccgx-ucsi", sizeof(i2c_dw_ccgx_ucsi->type));
+ i2c_dw_ccgx_ucsi->addr = 0x08;
+ i2c_dw_ccgx_ucsi->irq = i2cd->irq;
+
+ ccgx_client = i2c_new_client_device(&i2cd->adapter, i2c_dw_ccgx_ucsi);
+ if (!ccgx_client)
+ 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 |= AMD_NON_INTR_MODE;
+ 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 +323,9 @@ static int i2c_dw_pci_probe(struct pci_dev *pdev,
return r;
}

+ if (dev->flags & AMD_NON_INTR_MODE)
+ i2c_dw_populate_client(dev);
+
pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_put_autosuspend(&pdev->dev);
@@ -337,6 +389,10 @@ 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