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i2c-tegra.c
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i2c-tegra.c
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// SPDX-License-Identifier: GPL-2.0
/*
* drivers/i2c/busses/i2c-tegra.c
*
* Copyright (C) 2010 Google, Inc.
* Author: Colin Cross <ccross@android.com>
*/
#include <linux/acpi.h>
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>
#define BYTES_PER_FIFO_WORD 4
#define I2C_CNFG 0x000
#define I2C_CNFG_DEBOUNCE_CNT GENMASK(14, 12)
#define I2C_CNFG_PACKET_MODE_EN BIT(10)
#define I2C_CNFG_NEW_MASTER_FSM BIT(11)
#define I2C_CNFG_MULTI_MASTER_MODE BIT(17)
#define I2C_STATUS 0x01c
#define I2C_SL_CNFG 0x020
#define I2C_SL_CNFG_NACK BIT(1)
#define I2C_SL_CNFG_NEWSL BIT(2)
#define I2C_SL_ADDR1 0x02c
#define I2C_SL_ADDR2 0x030
#define I2C_TLOW_SEXT 0x034
#define I2C_TX_FIFO 0x050
#define I2C_RX_FIFO 0x054
#define I2C_PACKET_TRANSFER_STATUS 0x058
#define I2C_FIFO_CONTROL 0x05c
#define I2C_FIFO_CONTROL_TX_FLUSH BIT(1)
#define I2C_FIFO_CONTROL_RX_FLUSH BIT(0)
#define I2C_FIFO_CONTROL_TX_TRIG(x) (((x) - 1) << 5)
#define I2C_FIFO_CONTROL_RX_TRIG(x) (((x) - 1) << 2)
#define I2C_FIFO_STATUS 0x060
#define I2C_FIFO_STATUS_TX GENMASK(7, 4)
#define I2C_FIFO_STATUS_RX GENMASK(3, 0)
#define I2C_INT_MASK 0x064
#define I2C_INT_STATUS 0x068
#define I2C_INT_BUS_CLR_DONE BIT(11)
#define I2C_INT_PACKET_XFER_COMPLETE BIT(7)
#define I2C_INT_NO_ACK BIT(3)
#define I2C_INT_ARBITRATION_LOST BIT(2)
#define I2C_INT_TX_FIFO_DATA_REQ BIT(1)
#define I2C_INT_RX_FIFO_DATA_REQ BIT(0)
#define I2C_CLK_DIVISOR 0x06c
#define I2C_CLK_DIVISOR_STD_FAST_MODE GENMASK(31, 16)
#define I2C_CLK_DIVISOR_HSMODE GENMASK(15, 0)
#define DVC_CTRL_REG1 0x000
#define DVC_CTRL_REG1_INTR_EN BIT(10)
#define DVC_CTRL_REG3 0x008
#define DVC_CTRL_REG3_SW_PROG BIT(26)
#define DVC_CTRL_REG3_I2C_DONE_INTR_EN BIT(30)
#define DVC_STATUS 0x00c
#define DVC_STATUS_I2C_DONE_INTR BIT(30)
#define I2C_ERR_NONE 0x00
#define I2C_ERR_NO_ACK BIT(0)
#define I2C_ERR_ARBITRATION_LOST BIT(1)
#define I2C_ERR_UNKNOWN_INTERRUPT BIT(2)
#define I2C_ERR_RX_BUFFER_OVERFLOW BIT(3)
#define PACKET_HEADER0_HEADER_SIZE GENMASK(29, 28)
#define PACKET_HEADER0_PACKET_ID GENMASK(23, 16)
#define PACKET_HEADER0_CONT_ID GENMASK(15, 12)
#define PACKET_HEADER0_PROTOCOL GENMASK(7, 4)
#define PACKET_HEADER0_PROTOCOL_I2C 1
#define I2C_HEADER_CONT_ON_NAK BIT(21)
#define I2C_HEADER_READ BIT(19)
#define I2C_HEADER_10BIT_ADDR BIT(18)
#define I2C_HEADER_IE_ENABLE BIT(17)
#define I2C_HEADER_REPEAT_START BIT(16)
#define I2C_HEADER_CONTINUE_XFER BIT(15)
#define I2C_HEADER_SLAVE_ADDR_SHIFT 1
#define I2C_BUS_CLEAR_CNFG 0x084
#define I2C_BC_SCLK_THRESHOLD GENMASK(23, 16)
#define I2C_BC_STOP_COND BIT(2)
#define I2C_BC_TERMINATE BIT(1)
#define I2C_BC_ENABLE BIT(0)
#define I2C_BUS_CLEAR_STATUS 0x088
#define I2C_BC_STATUS BIT(0)
#define I2C_CONFIG_LOAD 0x08c
#define I2C_MSTR_CONFIG_LOAD BIT(0)
#define I2C_CLKEN_OVERRIDE 0x090
#define I2C_MST_CORE_CLKEN_OVR BIT(0)
#define I2C_INTERFACE_TIMING_0 0x094
#define I2C_INTERFACE_TIMING_THIGH GENMASK(13, 8)
#define I2C_INTERFACE_TIMING_TLOW GENMASK(5, 0)
#define I2C_INTERFACE_TIMING_1 0x098
#define I2C_INTERFACE_TIMING_TBUF GENMASK(29, 24)
#define I2C_INTERFACE_TIMING_TSU_STO GENMASK(21, 16)
#define I2C_INTERFACE_TIMING_THD_STA GENMASK(13, 8)
#define I2C_INTERFACE_TIMING_TSU_STA GENMASK(5, 0)
#define I2C_HS_INTERFACE_TIMING_0 0x09c
#define I2C_HS_INTERFACE_TIMING_THIGH GENMASK(13, 8)
#define I2C_HS_INTERFACE_TIMING_TLOW GENMASK(5, 0)
#define I2C_HS_INTERFACE_TIMING_1 0x0a0
#define I2C_HS_INTERFACE_TIMING_TSU_STO GENMASK(21, 16)
#define I2C_HS_INTERFACE_TIMING_THD_STA GENMASK(13, 8)
#define I2C_HS_INTERFACE_TIMING_TSU_STA GENMASK(5, 0)
#define I2C_MST_FIFO_CONTROL 0x0b4
#define I2C_MST_FIFO_CONTROL_RX_FLUSH BIT(0)
#define I2C_MST_FIFO_CONTROL_TX_FLUSH BIT(1)
#define I2C_MST_FIFO_CONTROL_RX_TRIG(x) (((x) - 1) << 4)
#define I2C_MST_FIFO_CONTROL_TX_TRIG(x) (((x) - 1) << 16)
#define I2C_MST_FIFO_STATUS 0x0b8
#define I2C_MST_FIFO_STATUS_TX GENMASK(23, 16)
#define I2C_MST_FIFO_STATUS_RX GENMASK(7, 0)
/* configuration load timeout in microseconds */
#define I2C_CONFIG_LOAD_TIMEOUT 1000000
/* packet header size in bytes */
#define I2C_PACKET_HEADER_SIZE 12
/*
* I2C Controller will use PIO mode for transfers up to 32 bytes in order to
* avoid DMA overhead, otherwise external APB DMA controller will be used.
* Note that the actual MAX PIO length is 20 bytes because 32 bytes include
* I2C_PACKET_HEADER_SIZE.
*/
#define I2C_PIO_MODE_PREFERRED_LEN 32
/*
* msg_end_type: The bus control which needs to be sent at end of transfer.
* @MSG_END_STOP: Send stop pulse.
* @MSG_END_REPEAT_START: Send repeat-start.
* @MSG_END_CONTINUE: Don't send stop or repeat-start.
*/
enum msg_end_type {
MSG_END_STOP,
MSG_END_REPEAT_START,
MSG_END_CONTINUE,
};
/**
* struct tegra_i2c_hw_feature : per hardware generation features
* @has_continue_xfer_support: continue-transfer supported
* @has_per_pkt_xfer_complete_irq: Has enable/disable capability for transfer
* completion interrupt on per packet basis.
* @has_config_load_reg: Has the config load register to load the new
* configuration.
* @clk_divisor_hs_mode: Clock divisor in HS mode.
* @clk_divisor_std_mode: Clock divisor in standard mode. It is
* applicable if there is no fast clock source i.e. single clock
* source.
* @clk_divisor_fast_mode: Clock divisor in fast mode. It is
* applicable if there is no fast clock source i.e. single clock
* source.
* @clk_divisor_fast_plus_mode: Clock divisor in fast mode plus. It is
* applicable if there is no fast clock source (i.e. single
* clock source).
* @has_multi_master_mode: The I2C controller supports running in single-master
* or multi-master mode.
* @has_slcg_override_reg: The I2C controller supports a register that
* overrides the second level clock gating.
* @has_mst_fifo: The I2C controller contains the new MST FIFO interface that
* provides additional features and allows for longer messages to
* be transferred in one go.
* @quirks: I2C adapter quirks for limiting write/read transfer size and not
* allowing 0 length transfers.
* @supports_bus_clear: Bus Clear support to recover from bus hang during
* SDA stuck low from device for some unknown reasons.
* @has_apb_dma: Support of APBDMA on corresponding Tegra chip.
* @tlow_std_mode: Low period of the clock in standard mode.
* @thigh_std_mode: High period of the clock in standard mode.
* @tlow_fast_fastplus_mode: Low period of the clock in fast/fast-plus modes.
* @thigh_fast_fastplus_mode: High period of the clock in fast/fast-plus modes.
* @setup_hold_time_std_mode: Setup and hold time for start and stop conditions
* in standard mode.
* @setup_hold_time_fast_fast_plus_mode: Setup and hold time for start and stop
* conditions in fast/fast-plus modes.
* @setup_hold_time_hs_mode: Setup and hold time for start and stop conditions
* in HS mode.
* @has_interface_timing_reg: Has interface timing register to program the tuned
* timing settings.
*/
struct tegra_i2c_hw_feature {
bool has_continue_xfer_support;
bool has_per_pkt_xfer_complete_irq;
bool has_config_load_reg;
u32 clk_divisor_hs_mode;
u32 clk_divisor_std_mode;
u32 clk_divisor_fast_mode;
u32 clk_divisor_fast_plus_mode;
bool has_multi_master_mode;
bool has_slcg_override_reg;
bool has_mst_fifo;
const struct i2c_adapter_quirks *quirks;
bool supports_bus_clear;
bool has_apb_dma;
u32 tlow_std_mode;
u32 thigh_std_mode;
u32 tlow_fast_fastplus_mode;
u32 thigh_fast_fastplus_mode;
u32 setup_hold_time_std_mode;
u32 setup_hold_time_fast_fast_plus_mode;
u32 setup_hold_time_hs_mode;
bool has_interface_timing_reg;
};
/**
* struct tegra_i2c_dev - per device I2C context
* @dev: device reference for power management
* @hw: Tegra I2C HW feature
* @adapter: core I2C layer adapter information
* @div_clk: clock reference for div clock of I2C controller
* @clocks: array of I2C controller clocks
* @nclocks: number of clocks in the array
* @rst: reset control for the I2C controller
* @base: ioremapped registers cookie
* @base_phys: physical base address of the I2C controller
* @cont_id: I2C controller ID, used for packet header
* @irq: IRQ number of transfer complete interrupt
* @is_dvc: identifies the DVC I2C controller, has a different register layout
* @is_vi: identifies the VI I2C controller, has a different register layout
* @msg_complete: transfer completion notifier
* @msg_buf_remaining: size of unsent data in the message buffer
* @msg_len: length of message in current transfer
* @msg_err: error code for completed message
* @msg_buf: pointer to current message data
* @msg_read: indicates that the transfer is a read access
* @timings: i2c timings information like bus frequency
* @multimaster_mode: indicates that I2C controller is in multi-master mode
* @tx_dma_chan: DMA transmit channel
* @rx_dma_chan: DMA receive channel
* @dma_phys: handle to DMA resources
* @dma_buf: pointer to allocated DMA buffer
* @dma_buf_size: DMA buffer size
* @dma_mode: indicates active DMA transfer
* @dma_complete: DMA completion notifier
* @atomic_mode: indicates active atomic transfer
*/
struct tegra_i2c_dev {
struct device *dev;
struct i2c_adapter adapter;
const struct tegra_i2c_hw_feature *hw;
struct reset_control *rst;
unsigned int cont_id;
unsigned int irq;
phys_addr_t base_phys;
void __iomem *base;
struct clk_bulk_data clocks[2];
unsigned int nclocks;
struct clk *div_clk;
struct i2c_timings timings;
struct completion msg_complete;
size_t msg_buf_remaining;
unsigned int msg_len;
int msg_err;
u8 *msg_buf;
struct completion dma_complete;
struct dma_chan *tx_dma_chan;
struct dma_chan *rx_dma_chan;
unsigned int dma_buf_size;
struct device *dma_dev;
dma_addr_t dma_phys;
void *dma_buf;
bool multimaster_mode;
bool atomic_mode;
bool dma_mode;
bool msg_read;
bool is_dvc;
bool is_vi;
};
static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
unsigned int reg)
{
writel_relaxed(val, i2c_dev->base + reg);
}
static u32 dvc_readl(struct tegra_i2c_dev *i2c_dev, unsigned int reg)
{
return readl_relaxed(i2c_dev->base + reg);
}
/*
* If necessary, i2c_writel() and i2c_readl() will offset the register
* in order to talk to the I2C block inside the DVC block.
*/
static u32 tegra_i2c_reg_addr(struct tegra_i2c_dev *i2c_dev, unsigned int reg)
{
if (i2c_dev->is_dvc)
reg += (reg >= I2C_TX_FIFO) ? 0x10 : 0x40;
else if (i2c_dev->is_vi)
reg = 0xc00 + (reg << 2);
return reg;
}
static void i2c_writel(struct tegra_i2c_dev *i2c_dev, u32 val, unsigned int reg)
{
writel_relaxed(val, i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
/* read back register to make sure that register writes completed */
if (reg != I2C_TX_FIFO)
readl_relaxed(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
else if (i2c_dev->is_vi)
readl_relaxed(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, I2C_INT_STATUS));
}
static u32 i2c_readl(struct tegra_i2c_dev *i2c_dev, unsigned int reg)
{
return readl_relaxed(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
}
static void i2c_writesl(struct tegra_i2c_dev *i2c_dev, void *data,
unsigned int reg, unsigned int len)
{
writesl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len);
}
static void i2c_writesl_vi(struct tegra_i2c_dev *i2c_dev, void *data,
unsigned int reg, unsigned int len)
{
u32 *data32 = data;
/*
* VI I2C controller has known hardware bug where writes get stuck
* when immediate multiple writes happen to TX_FIFO register.
* Recommended software work around is to read I2C register after
* each write to TX_FIFO register to flush out the data.
*/
while (len--)
i2c_writel(i2c_dev, *data32++, reg);
}
static void i2c_readsl(struct tegra_i2c_dev *i2c_dev, void *data,
unsigned int reg, unsigned int len)
{
readsl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len);
}
static void tegra_i2c_mask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask)
{
u32 int_mask;
int_mask = i2c_readl(i2c_dev, I2C_INT_MASK) & ~mask;
i2c_writel(i2c_dev, int_mask, I2C_INT_MASK);
}
static void tegra_i2c_unmask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask)
{
u32 int_mask;
int_mask = i2c_readl(i2c_dev, I2C_INT_MASK) | mask;
i2c_writel(i2c_dev, int_mask, I2C_INT_MASK);
}
static void tegra_i2c_dma_complete(void *args)
{
struct tegra_i2c_dev *i2c_dev = args;
complete(&i2c_dev->dma_complete);
}
static int tegra_i2c_dma_submit(struct tegra_i2c_dev *i2c_dev, size_t len)
{
struct dma_async_tx_descriptor *dma_desc;
enum dma_transfer_direction dir;
struct dma_chan *chan;
dev_dbg(i2c_dev->dev, "starting DMA for length: %zu\n", len);
reinit_completion(&i2c_dev->dma_complete);
dir = i2c_dev->msg_read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV;
chan = i2c_dev->msg_read ? i2c_dev->rx_dma_chan : i2c_dev->tx_dma_chan;
dma_desc = dmaengine_prep_slave_single(chan, i2c_dev->dma_phys,
len, dir, DMA_PREP_INTERRUPT |
DMA_CTRL_ACK);
if (!dma_desc) {
dev_err(i2c_dev->dev, "failed to get %s DMA descriptor\n",
i2c_dev->msg_read ? "RX" : "TX");
return -EINVAL;
}
dma_desc->callback = tegra_i2c_dma_complete;
dma_desc->callback_param = i2c_dev;
dmaengine_submit(dma_desc);
dma_async_issue_pending(chan);
return 0;
}
static void tegra_i2c_release_dma(struct tegra_i2c_dev *i2c_dev)
{
if (i2c_dev->dma_buf) {
dma_free_coherent(i2c_dev->dma_dev, i2c_dev->dma_buf_size,
i2c_dev->dma_buf, i2c_dev->dma_phys);
i2c_dev->dma_buf = NULL;
}
if (i2c_dev->tx_dma_chan) {
dma_release_channel(i2c_dev->tx_dma_chan);
i2c_dev->tx_dma_chan = NULL;
}
if (i2c_dev->rx_dma_chan) {
dma_release_channel(i2c_dev->rx_dma_chan);
i2c_dev->rx_dma_chan = NULL;
}
}
static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev)
{
struct dma_chan *chan;
dma_addr_t dma_phys;
u32 *dma_buf;
int err;
if (i2c_dev->is_vi)
return 0;
if (i2c_dev->hw->has_apb_dma) {
if (!IS_ENABLED(CONFIG_TEGRA20_APB_DMA)) {
dev_dbg(i2c_dev->dev, "APB DMA support not enabled\n");
return 0;
}
} else if (!IS_ENABLED(CONFIG_TEGRA186_GPC_DMA)) {
dev_dbg(i2c_dev->dev, "GPC DMA support not enabled\n");
return 0;
}
chan = dma_request_chan(i2c_dev->dev, "rx");
if (IS_ERR(chan)) {
err = PTR_ERR(chan);
goto err_out;
}
i2c_dev->rx_dma_chan = chan;
chan = dma_request_chan(i2c_dev->dev, "tx");
if (IS_ERR(chan)) {
err = PTR_ERR(chan);
goto err_out;
}
i2c_dev->tx_dma_chan = chan;
WARN_ON(i2c_dev->tx_dma_chan->device != i2c_dev->rx_dma_chan->device);
i2c_dev->dma_dev = chan->device->dev;
i2c_dev->dma_buf_size = i2c_dev->hw->quirks->max_write_len +
I2C_PACKET_HEADER_SIZE;
dma_buf = dma_alloc_coherent(i2c_dev->dma_dev, i2c_dev->dma_buf_size,
&dma_phys, GFP_KERNEL | __GFP_NOWARN);
if (!dma_buf) {
dev_err(i2c_dev->dev, "failed to allocate DMA buffer\n");
err = -ENOMEM;
goto err_out;
}
i2c_dev->dma_buf = dma_buf;
i2c_dev->dma_phys = dma_phys;
return 0;
err_out:
tegra_i2c_release_dma(i2c_dev);
if (err != -EPROBE_DEFER) {
dev_err(i2c_dev->dev, "cannot use DMA: %d\n", err);
dev_err(i2c_dev->dev, "falling back to PIO\n");
return 0;
}
return err;
}
/*
* One of the Tegra I2C blocks is inside the DVC (Digital Voltage Controller)
* block. This block is identical to the rest of the I2C blocks, except that
* it only supports master mode, it has registers moved around, and it needs
* some extra init to get it into I2C mode. The register moves are handled
* by i2c_readl() and i2c_writel().
*/
static void tegra_dvc_init(struct tegra_i2c_dev *i2c_dev)
{
u32 val;
val = dvc_readl(i2c_dev, DVC_CTRL_REG3);
val |= DVC_CTRL_REG3_SW_PROG;
val |= DVC_CTRL_REG3_I2C_DONE_INTR_EN;
dvc_writel(i2c_dev, val, DVC_CTRL_REG3);
val = dvc_readl(i2c_dev, DVC_CTRL_REG1);
val |= DVC_CTRL_REG1_INTR_EN;
dvc_writel(i2c_dev, val, DVC_CTRL_REG1);
}
static void tegra_i2c_vi_init(struct tegra_i2c_dev *i2c_dev)
{
u32 value;
value = FIELD_PREP(I2C_INTERFACE_TIMING_THIGH, 2) |
FIELD_PREP(I2C_INTERFACE_TIMING_TLOW, 4);
i2c_writel(i2c_dev, value, I2C_INTERFACE_TIMING_0);
value = FIELD_PREP(I2C_INTERFACE_TIMING_TBUF, 4) |
FIELD_PREP(I2C_INTERFACE_TIMING_TSU_STO, 7) |
FIELD_PREP(I2C_INTERFACE_TIMING_THD_STA, 4) |
FIELD_PREP(I2C_INTERFACE_TIMING_TSU_STA, 4);
i2c_writel(i2c_dev, value, I2C_INTERFACE_TIMING_1);
value = FIELD_PREP(I2C_HS_INTERFACE_TIMING_THIGH, 3) |
FIELD_PREP(I2C_HS_INTERFACE_TIMING_TLOW, 8);
i2c_writel(i2c_dev, value, I2C_HS_INTERFACE_TIMING_0);
value = FIELD_PREP(I2C_HS_INTERFACE_TIMING_TSU_STO, 11) |
FIELD_PREP(I2C_HS_INTERFACE_TIMING_THD_STA, 11) |
FIELD_PREP(I2C_HS_INTERFACE_TIMING_TSU_STA, 11);
i2c_writel(i2c_dev, value, I2C_HS_INTERFACE_TIMING_1);
value = FIELD_PREP(I2C_BC_SCLK_THRESHOLD, 9) | I2C_BC_STOP_COND;
i2c_writel(i2c_dev, value, I2C_BUS_CLEAR_CNFG);
i2c_writel(i2c_dev, 0x0, I2C_TLOW_SEXT);
}
static int tegra_i2c_poll_register(struct tegra_i2c_dev *i2c_dev,
u32 reg, u32 mask, u32 delay_us,
u32 timeout_us)
{
void __iomem *addr = i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg);
u32 val;
if (!i2c_dev->atomic_mode)
return readl_relaxed_poll_timeout(addr, val, !(val & mask),
delay_us, timeout_us);
return readl_relaxed_poll_timeout_atomic(addr, val, !(val & mask),
delay_us, timeout_us);
}
static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
{
u32 mask, val, offset;
int err;
if (i2c_dev->hw->has_mst_fifo) {
mask = I2C_MST_FIFO_CONTROL_TX_FLUSH |
I2C_MST_FIFO_CONTROL_RX_FLUSH;
offset = I2C_MST_FIFO_CONTROL;
} else {
mask = I2C_FIFO_CONTROL_TX_FLUSH |
I2C_FIFO_CONTROL_RX_FLUSH;
offset = I2C_FIFO_CONTROL;
}
val = i2c_readl(i2c_dev, offset);
val |= mask;
i2c_writel(i2c_dev, val, offset);
err = tegra_i2c_poll_register(i2c_dev, offset, mask, 1000, 1000000);
if (err) {
dev_err(i2c_dev->dev, "failed to flush FIFO\n");
return err;
}
return 0;
}
static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
{
int err;
if (!i2c_dev->hw->has_config_load_reg)
return 0;
i2c_writel(i2c_dev, I2C_MSTR_CONFIG_LOAD, I2C_CONFIG_LOAD);
err = tegra_i2c_poll_register(i2c_dev, I2C_CONFIG_LOAD, 0xffffffff,
1000, I2C_CONFIG_LOAD_TIMEOUT);
if (err) {
dev_err(i2c_dev->dev, "failed to load config\n");
return err;
}
return 0;
}
static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
{
u32 val, clk_divisor, clk_multiplier, tsu_thd, tlow, thigh, non_hs_mode;
acpi_handle handle = ACPI_HANDLE(i2c_dev->dev);
struct i2c_timings *t = &i2c_dev->timings;
int err;
/*
* The reset shouldn't ever fail in practice. The failure will be a
* sign of a severe problem that needs to be resolved. Still we don't
* want to fail the initialization completely because this may break
* kernel boot up since voltage regulators use I2C. Hence, we will
* emit a noisy warning on error, which won't stay unnoticed and
* won't hose machine entirely.
*/
if (handle)
err = acpi_evaluate_object(handle, "_RST", NULL, NULL);
else
err = reset_control_reset(i2c_dev->rst);
WARN_ON_ONCE(err);
if (i2c_dev->is_dvc)
tegra_dvc_init(i2c_dev);
val = I2C_CNFG_NEW_MASTER_FSM | I2C_CNFG_PACKET_MODE_EN |
FIELD_PREP(I2C_CNFG_DEBOUNCE_CNT, 2);
if (i2c_dev->hw->has_multi_master_mode)
val |= I2C_CNFG_MULTI_MASTER_MODE;
i2c_writel(i2c_dev, val, I2C_CNFG);
i2c_writel(i2c_dev, 0, I2C_INT_MASK);
if (i2c_dev->is_vi)
tegra_i2c_vi_init(i2c_dev);
switch (t->bus_freq_hz) {
case I2C_MAX_STANDARD_MODE_FREQ + 1 ... I2C_MAX_FAST_MODE_PLUS_FREQ:
default:
tlow = i2c_dev->hw->tlow_fast_fastplus_mode;
thigh = i2c_dev->hw->thigh_fast_fastplus_mode;
tsu_thd = i2c_dev->hw->setup_hold_time_fast_fast_plus_mode;
if (t->bus_freq_hz > I2C_MAX_FAST_MODE_FREQ)
non_hs_mode = i2c_dev->hw->clk_divisor_fast_plus_mode;
else
non_hs_mode = i2c_dev->hw->clk_divisor_fast_mode;
break;
case 0 ... I2C_MAX_STANDARD_MODE_FREQ:
tlow = i2c_dev->hw->tlow_std_mode;
thigh = i2c_dev->hw->thigh_std_mode;
tsu_thd = i2c_dev->hw->setup_hold_time_std_mode;
non_hs_mode = i2c_dev->hw->clk_divisor_std_mode;
break;
}
/* make sure clock divisor programmed correctly */
clk_divisor = FIELD_PREP(I2C_CLK_DIVISOR_HSMODE,
i2c_dev->hw->clk_divisor_hs_mode) |
FIELD_PREP(I2C_CLK_DIVISOR_STD_FAST_MODE, non_hs_mode);
i2c_writel(i2c_dev, clk_divisor, I2C_CLK_DIVISOR);
if (i2c_dev->hw->has_interface_timing_reg) {
val = FIELD_PREP(I2C_INTERFACE_TIMING_THIGH, thigh) |
FIELD_PREP(I2C_INTERFACE_TIMING_TLOW, tlow);
i2c_writel(i2c_dev, val, I2C_INTERFACE_TIMING_0);
}
/*
* Configure setup and hold times only when tsu_thd is non-zero.
* Otherwise, preserve the chip default values.
*/
if (i2c_dev->hw->has_interface_timing_reg && tsu_thd)
i2c_writel(i2c_dev, tsu_thd, I2C_INTERFACE_TIMING_1);
clk_multiplier = (tlow + thigh + 2) * (non_hs_mode + 1);
err = clk_set_rate(i2c_dev->div_clk,
t->bus_freq_hz * clk_multiplier);
if (err) {
dev_err(i2c_dev->dev, "failed to set div-clk rate: %d\n", err);
return err;
}
if (!i2c_dev->is_dvc && !i2c_dev->is_vi) {
u32 sl_cfg = i2c_readl(i2c_dev, I2C_SL_CNFG);
sl_cfg |= I2C_SL_CNFG_NACK | I2C_SL_CNFG_NEWSL;
i2c_writel(i2c_dev, sl_cfg, I2C_SL_CNFG);
i2c_writel(i2c_dev, 0xfc, I2C_SL_ADDR1);
i2c_writel(i2c_dev, 0x00, I2C_SL_ADDR2);
}
err = tegra_i2c_flush_fifos(i2c_dev);
if (err)
return err;
if (i2c_dev->multimaster_mode && i2c_dev->hw->has_slcg_override_reg)
i2c_writel(i2c_dev, I2C_MST_CORE_CLKEN_OVR, I2C_CLKEN_OVERRIDE);
err = tegra_i2c_wait_for_config_load(i2c_dev);
if (err)
return err;
return 0;
}
static int tegra_i2c_disable_packet_mode(struct tegra_i2c_dev *i2c_dev)
{
u32 cnfg;
/*
* NACK interrupt is generated before the I2C controller generates
* the STOP condition on the bus. So, wait for 2 clock periods
* before disabling the controller so that the STOP condition has
* been delivered properly.
*/
udelay(DIV_ROUND_UP(2 * 1000000, i2c_dev->timings.bus_freq_hz));
cnfg = i2c_readl(i2c_dev, I2C_CNFG);
if (cnfg & I2C_CNFG_PACKET_MODE_EN)
i2c_writel(i2c_dev, cnfg & ~I2C_CNFG_PACKET_MODE_EN, I2C_CNFG);
return tegra_i2c_wait_for_config_load(i2c_dev);
}
static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
{
size_t buf_remaining = i2c_dev->msg_buf_remaining;
unsigned int words_to_transfer, rx_fifo_avail;
u8 *buf = i2c_dev->msg_buf;
u32 val;
/*
* Catch overflow due to message fully sent before the check for
* RX FIFO availability.
*/
if (WARN_ON_ONCE(!(i2c_dev->msg_buf_remaining)))
return -EINVAL;
if (i2c_dev->hw->has_mst_fifo) {
val = i2c_readl(i2c_dev, I2C_MST_FIFO_STATUS);
rx_fifo_avail = FIELD_GET(I2C_MST_FIFO_STATUS_RX, val);
} else {
val = i2c_readl(i2c_dev, I2C_FIFO_STATUS);
rx_fifo_avail = FIELD_GET(I2C_FIFO_STATUS_RX, val);
}
/* round down to exclude partial word at the end of buffer */
words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
if (words_to_transfer > rx_fifo_avail)
words_to_transfer = rx_fifo_avail;
i2c_readsl(i2c_dev, buf, I2C_RX_FIFO, words_to_transfer);
buf += words_to_transfer * BYTES_PER_FIFO_WORD;
buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
rx_fifo_avail -= words_to_transfer;
/*
* If there is a partial word at the end of buffer, handle it
* manually to prevent overwriting past the end of buffer.
*/
if (rx_fifo_avail > 0 && buf_remaining > 0) {
/*
* buf_remaining > 3 check not needed as rx_fifo_avail == 0
* when (words_to_transfer was > rx_fifo_avail) earlier
* in this function.
*/
val = i2c_readl(i2c_dev, I2C_RX_FIFO);
val = cpu_to_le32(val);
memcpy(buf, &val, buf_remaining);
buf_remaining = 0;
rx_fifo_avail--;
}
/* RX FIFO must be drained, otherwise it's an Overflow case. */
if (WARN_ON_ONCE(rx_fifo_avail))
return -EINVAL;
i2c_dev->msg_buf_remaining = buf_remaining;
i2c_dev->msg_buf = buf;
return 0;
}
static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
{
size_t buf_remaining = i2c_dev->msg_buf_remaining;
unsigned int words_to_transfer, tx_fifo_avail;
u8 *buf = i2c_dev->msg_buf;
u32 val;
if (i2c_dev->hw->has_mst_fifo) {
val = i2c_readl(i2c_dev, I2C_MST_FIFO_STATUS);
tx_fifo_avail = FIELD_GET(I2C_MST_FIFO_STATUS_TX, val);
} else {
val = i2c_readl(i2c_dev, I2C_FIFO_STATUS);
tx_fifo_avail = FIELD_GET(I2C_FIFO_STATUS_TX, val);
}
/* round down to exclude partial word at the end of buffer */
words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
/*
* This hunk pushes 4 bytes at a time into the TX FIFO.
*
* It's very common to have < 4 bytes, hence there is no word
* to push if we have less than 4 bytes to transfer.
*/
if (words_to_transfer) {
if (words_to_transfer > tx_fifo_avail)
words_to_transfer = tx_fifo_avail;
/*
* Update state before writing to FIFO. Note that this may
* cause us to finish writing all bytes (AKA buf_remaining
* goes to 0), hence we have a potential for an interrupt
* (PACKET_XFER_COMPLETE is not maskable), but GIC interrupt
* is disabled at this point.
*/
buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
tx_fifo_avail -= words_to_transfer;
i2c_dev->msg_buf_remaining = buf_remaining;
i2c_dev->msg_buf = buf + words_to_transfer * BYTES_PER_FIFO_WORD;
if (i2c_dev->is_vi)
i2c_writesl_vi(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
else
i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
buf += words_to_transfer * BYTES_PER_FIFO_WORD;
}
/*
* If there is a partial word at the end of buffer, handle it manually
* to prevent reading past the end of buffer, which could cross a page
* boundary and fault.
*/
if (tx_fifo_avail > 0 && buf_remaining > 0) {
/*
* buf_remaining > 3 check not needed as tx_fifo_avail == 0
* when (words_to_transfer was > tx_fifo_avail) earlier
* in this function for non-zero words_to_transfer.
*/
memcpy(&val, buf, buf_remaining);
val = le32_to_cpu(val);
i2c_dev->msg_buf_remaining = 0;
i2c_dev->msg_buf = NULL;
i2c_writel(i2c_dev, val, I2C_TX_FIFO);
}
return 0;
}
static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
{
const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
struct tegra_i2c_dev *i2c_dev = dev_id;
u32 status;
status = i2c_readl(i2c_dev, I2C_INT_STATUS);
if (status == 0) {
dev_warn(i2c_dev->dev, "IRQ status 0 %08x %08x %08x\n",
i2c_readl(i2c_dev, I2C_PACKET_TRANSFER_STATUS),
i2c_readl(i2c_dev, I2C_STATUS),
i2c_readl(i2c_dev, I2C_CNFG));
i2c_dev->msg_err |= I2C_ERR_UNKNOWN_INTERRUPT;
goto err;
}
if (status & status_err) {
tegra_i2c_disable_packet_mode(i2c_dev);
if (status & I2C_INT_NO_ACK)
i2c_dev->msg_err |= I2C_ERR_NO_ACK;
if (status & I2C_INT_ARBITRATION_LOST)
i2c_dev->msg_err |= I2C_ERR_ARBITRATION_LOST;
goto err;
}
/*
* I2C transfer is terminated during the bus clear, so skip
* processing the other interrupts.
*/
if (i2c_dev->hw->supports_bus_clear && (status & I2C_INT_BUS_CLR_DONE))
goto err;
if (!i2c_dev->dma_mode) {
if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) {
if (tegra_i2c_empty_rx_fifo(i2c_dev)) {
/*
* Overflow error condition: message fully sent,
* with no XFER_COMPLETE interrupt but hardware
* asks to transfer more.
*/
i2c_dev->msg_err |= I2C_ERR_RX_BUFFER_OVERFLOW;
goto err;
}
}
if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) {
if (i2c_dev->msg_buf_remaining)
tegra_i2c_fill_tx_fifo(i2c_dev);
else
tegra_i2c_mask_irq(i2c_dev,
I2C_INT_TX_FIFO_DATA_REQ);
}
}
i2c_writel(i2c_dev, status, I2C_INT_STATUS);
if (i2c_dev->is_dvc)
dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS);
/*
* During message read XFER_COMPLETE interrupt is triggered prior to
* DMA completion and during message write XFER_COMPLETE interrupt is
* triggered after DMA completion.
*
* PACKETS_XFER_COMPLETE indicates completion of all bytes of transfer,
* so forcing msg_buf_remaining to 0 in DMA mode.
*/
if (status & I2C_INT_PACKET_XFER_COMPLETE) {
if (i2c_dev->dma_mode)
i2c_dev->msg_buf_remaining = 0;
/*
* Underflow error condition: XFER_COMPLETE before message
* fully sent.
*/
if (WARN_ON_ONCE(i2c_dev->msg_buf_remaining)) {
i2c_dev->msg_err |= I2C_ERR_UNKNOWN_INTERRUPT;
goto err;
}
complete(&i2c_dev->msg_complete);
}
goto done;
err:
/* mask all interrupts on error */
tegra_i2c_mask_irq(i2c_dev,
I2C_INT_NO_ACK |
I2C_INT_ARBITRATION_LOST |
I2C_INT_PACKET_XFER_COMPLETE |
I2C_INT_TX_FIFO_DATA_REQ |
I2C_INT_RX_FIFO_DATA_REQ);
if (i2c_dev->hw->supports_bus_clear)
tegra_i2c_mask_irq(i2c_dev, I2C_INT_BUS_CLR_DONE);
i2c_writel(i2c_dev, status, I2C_INT_STATUS);
if (i2c_dev->is_dvc)
dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS);
if (i2c_dev->dma_mode) {
if (i2c_dev->msg_read)
dmaengine_terminate_async(i2c_dev->rx_dma_chan);
else
dmaengine_terminate_async(i2c_dev->tx_dma_chan);
complete(&i2c_dev->dma_complete);
}
complete(&i2c_dev->msg_complete);
done:
return IRQ_HANDLED;
}
static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
size_t len)
{
struct dma_slave_config slv_config = {0};
u32 val, reg, dma_burst, reg_offset;
struct dma_chan *chan;
int err;
if (i2c_dev->hw->has_mst_fifo)