diff options
| -rw-r--r-- | drivers/i2c/busses/i2c-mlxbf.c | 320 |
1 files changed, 149 insertions, 171 deletions
diff --git a/drivers/i2c/busses/i2c-mlxbf.c b/drivers/i2c/busses/i2c-mlxbf.c index 78b2bc9b0a34..e9e700012136 100644 --- a/drivers/i2c/busses/i2c-mlxbf.c +++ b/drivers/i2c/busses/i2c-mlxbf.c @@ -298,9 +298,6 @@ static u64 mlxbf_i2c_corepll_frequency; #define MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT 7 #define MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK GENMASK(6, 0) -#define MLXBF_I2C_SLAVE_ADDR_ENABLED(addr) \ - ((addr) & (1 << MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT)) - /* * Timeout is given in microsends. Note also that timeout handling is not * exact. @@ -426,7 +423,7 @@ struct mlxbf_i2c_priv { u64 frequency; /* Core frequency in Hz. */ int bus; /* Physical bus identifier. */ int irq; - struct i2c_client *slave; + struct i2c_client *slave[MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT]; }; static struct mlxbf_i2c_resource mlxbf_i2c_coalesce_res[] = { @@ -1543,25 +1540,23 @@ static int mlxbf_i2c_calculate_corepll_freq(struct platform_device *pdev, return 0; } -static int mlxbf_slave_enable(struct mlxbf_i2c_priv *priv, u8 addr) +static int mlxbf_i2c_slave_enable(struct mlxbf_i2c_priv *priv, + struct i2c_client *slave) { - u32 slave_reg, slave_reg_tmp, slave_reg_avail, slave_addr_mask; - u8 reg, reg_cnt, byte, addr_tmp, reg_avail, byte_avail; - bool avail, disabled; - - disabled = false; - avail = false; + u8 reg, reg_cnt, byte, addr_tmp; + u32 slave_reg, slave_reg_tmp; if (!priv) return -EPERM; reg_cnt = MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT >> 2; - slave_addr_mask = MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK; /* * Read the slave registers. There are 4 * 32-bit slave registers. - * Each slave register can hold up to 4 * 8-bit slave configuration - * (7-bit address, 1 status bit (1 if enabled, 0 if not)). + * Each slave register can hold up to 4 * 8-bit slave configuration: + * 1) A 7-bit address + * 2) And a status bit (1 if enabled, 0 if not). + * Look for the next available slave register slot. */ for (reg = 0; reg < reg_cnt; reg++) { slave_reg = readl(priv->smbus->io + @@ -1576,121 +1571,87 @@ static int mlxbf_slave_enable(struct mlxbf_i2c_priv *priv, u8 addr) addr_tmp = slave_reg_tmp & GENMASK(7, 0); /* - * Mark the first available slave address slot, i.e. its - * enabled bit should be unset. This slot might be used - * later on to register our slave. - */ - if (!avail && !MLXBF_I2C_SLAVE_ADDR_ENABLED(addr_tmp)) { - avail = true; - reg_avail = reg; - byte_avail = byte; - slave_reg_avail = slave_reg; - } - - /* - * Parse slave address bytes and check whether the - * slave address already exists and it's enabled, - * i.e. most significant bit is set. + * If an enable bit is not set in the + * MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG register, then the + * slave address slot associated with that bit is + * free. So set the enable bit and write the + * slave address bits. */ - if ((addr_tmp & slave_addr_mask) == addr) { - if (MLXBF_I2C_SLAVE_ADDR_ENABLED(addr_tmp)) - return 0; - disabled = true; - break; + if (!(addr_tmp & MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT)) { + slave_reg &= ~(MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK << (byte * 8)); + slave_reg |= (slave->addr << (byte * 8)); + slave_reg |= MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT << (byte * 8); + writel(slave_reg, priv->smbus->io + + MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + + (reg * 0x4)); + + /* + * Set the slave at the corresponding index. + */ + priv->slave[(reg * 4) + byte] = slave; + + return 0; } /* Parse next byte. */ slave_reg_tmp >>= 8; } - - /* Exit the loop if the slave address is found. */ - if (disabled) - break; } - if (!avail && !disabled) - return -EINVAL; /* No room for a new slave address. */ - - if (avail && !disabled) { - reg = reg_avail; - byte = byte_avail; - /* Set the slave address. */ - slave_reg_avail &= ~(slave_addr_mask << (byte * 8)); - slave_reg_avail |= addr << (byte * 8); - slave_reg = slave_reg_avail; - } - - /* Enable the slave address and update the register. */ - slave_reg |= (1 << MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT) << (byte * 8); - writel(slave_reg, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + - reg * 0x4); - - return 0; + return -EBUSY; } -static int mlxbf_slave_disable(struct mlxbf_i2c_priv *priv) +static int mlxbf_i2c_slave_disable(struct mlxbf_i2c_priv *priv, u8 addr) { - u32 slave_reg, slave_reg_tmp, slave_addr_mask; - u8 addr, addr_tmp, reg, reg_cnt, slave_byte; - struct i2c_client *client = priv->slave; - bool exist; + u8 addr_tmp, reg, reg_cnt, byte; + u32 slave_reg, slave_reg_tmp; - exist = false; - - addr = client->addr; reg_cnt = MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT >> 2; - slave_addr_mask = MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK; /* * Read the slave registers. There are 4 * 32-bit slave registers. - * Each slave register can hold up to 4 * 8-bit slave configuration - * (7-bit address, 1 status bit (1 if enabled, 0 if not)). + * Each slave register can hold up to 4 * 8-bit slave configuration: + * 1) A 7-bit address + * 2) And a status bit (1 if enabled, 0 if not). + * Check if addr is present in the registers. */ for (reg = 0; reg < reg_cnt; reg++) { slave_reg = readl(priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + reg * 0x4); /* Check whether the address slots are empty. */ - if (slave_reg == 0) + if (!slave_reg) continue; /* - * Each register holds 4 slave addresses. So, we have to keep - * the byte order consistent with the value read in order to - * update the register correctly, if needed. + * Check if addr matches any of the 4 slave addresses + * in the register. */ slave_reg_tmp = slave_reg; - slave_byte = 0; - while (slave_reg_tmp != 0) { - addr_tmp = slave_reg_tmp & slave_addr_mask; + for (byte = 0; byte < 4; byte++) { + addr_tmp = slave_reg_tmp & MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK; /* * Parse slave address bytes and check whether the * slave address already exists. */ if (addr_tmp == addr) { - exist = true; - break; + /* Clear the slave address slot. */ + slave_reg &= ~(GENMASK(7, 0) << (byte * 8)); + writel(slave_reg, priv->smbus->io + + MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + + (reg * 0x4)); + /* Free slave at the corresponding index */ + priv->slave[(reg * 4) + byte] = NULL; + + return 0; } /* Parse next byte. */ slave_reg_tmp >>= 8; - slave_byte += 1; } - - /* Exit the loop if the slave address is found. */ - if (exist) - break; } - if (!exist) - return 0; /* Slave is not registered, nothing to do. */ - - /* Cleanup the slave address slot. */ - slave_reg &= ~(GENMASK(7, 0) << (slave_byte * 8)); - writel(slave_reg, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + - reg * 0x4); - - return 0; + return -ENXIO; } static int mlxbf_i2c_init_coalesce(struct platform_device *pdev, @@ -1852,72 +1813,81 @@ static bool mlxbf_smbus_slave_wait_for_idle(struct mlxbf_i2c_priv *priv, return false; } -/* Send byte to 'external' smbus master. */ -static int mlxbf_smbus_irq_send(struct mlxbf_i2c_priv *priv, u8 recv_bytes) +static struct i2c_client *mlxbf_i2c_get_slave_from_addr( + struct mlxbf_i2c_priv *priv, u8 addr) { - u8 data_desc[MLXBF_I2C_SLAVE_DATA_DESC_SIZE] = { 0 }; - u8 write_size, pec_en, addr, byte, value, byte_cnt, desc_size; - struct i2c_client *slave = priv->slave; - u32 control32, data32; - int ret; + int i; - if (!slave) - return -EINVAL; + for (i = 0; i < MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT; i++) { + if (!priv->slave[i]) + continue; - addr = 0; - byte = 0; - desc_size = MLXBF_I2C_SLAVE_DATA_DESC_SIZE; + if (priv->slave[i]->addr == addr) + return priv->slave[i]; + } + + return NULL; +} + +/* + * Send byte to 'external' smbus master. This function is executed when + * an external smbus master wants to read data from the BlueField. + */ +static int mlxbf_i2c_irq_send(struct mlxbf_i2c_priv *priv, u8 recv_bytes) +{ + u8 data_desc[MLXBF_I2C_SLAVE_DATA_DESC_SIZE] = { 0 }; + u8 write_size, pec_en, addr, value, byte_cnt; + struct i2c_client *slave; + u32 control32, data32; + int ret = 0; /* - * Read bytes received from the external master. These bytes should - * be located in the first data descriptor register of the slave GW. - * These bytes are the slave address byte and the internal register - * address, if supplied. + * Read the first byte received from the external master to + * determine the slave address. This byte is located in the + * first data descriptor register of the slave GW. */ - if (recv_bytes > 0) { - data32 = ioread32be(priv->smbus->io + - MLXBF_I2C_SLAVE_DATA_DESC_ADDR); - - /* Parse the received bytes. */ - switch (recv_bytes) { - case 2: - byte = (data32 >> 8) & GENMASK(7, 0); - fallthrough; - case 1: - addr = (data32 & GENMASK(7, 0)) >> 1; - } + data32 = ioread32be(priv->smbus->io + + MLXBF_I2C_SLAVE_DATA_DESC_ADDR); + addr = (data32 & GENMASK(7, 0)) >> 1; - /* Check whether it's our slave address. */ - if (slave->addr != addr) - return -EINVAL; + /* + * Check if the slave address received in the data descriptor register + * matches any of the slave addresses registered. If there is a match, + * set the slave. + */ + slave = mlxbf_i2c_get_slave_from_addr(priv, addr); + if (!slave) { + ret = -ENXIO; + goto clear_csr; } /* - * I2C read transactions may start by a WRITE followed by a READ. - * Indeed, most slave devices would expect the internal address - * following the slave address byte. So, write that byte first, - * and then, send the requested data bytes to the master. + * An I2C read can consist of a WRITE bit transaction followed by + * a READ bit transaction. Indeed, slave devices often expect + * the slave address to be followed by the internal address. + * So, write the internal address byte first, and then, send the + * requested data to the master. */ if (recv_bytes > 1) { i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value); - value = byte; + value = (data32 >> 8) & GENMASK(7, 0); ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value); i2c_slave_event(slave, I2C_SLAVE_STOP, &value); if (ret < 0) - return ret; + goto clear_csr; } /* - * Now, send data to the master; currently, the driver supports - * READ_BYTE, READ_WORD and BLOCK READ protocols. Note that the - * hardware can send up to 128 bytes per transfer. That is the - * size of its data registers. + * Send data to the master. Currently, the driver supports + * READ_BYTE, READ_WORD and BLOCK READ protocols. The + * hardware can send up to 128 bytes per transfer which is + * the total size of the data registers. */ i2c_slave_event(slave, I2C_SLAVE_READ_REQUESTED, &value); - for (byte_cnt = 0; byte_cnt < desc_size; byte_cnt++) { + for (byte_cnt = 0; byte_cnt < MLXBF_I2C_SLAVE_DATA_DESC_SIZE; byte_cnt++) { data_desc[byte_cnt] = value; i2c_slave_event(slave, I2C_SLAVE_READ_PROCESSED, &value); } @@ -1925,8 +1895,6 @@ static int mlxbf_smbus_irq_send(struct mlxbf_i2c_priv *priv, u8 recv_bytes) /* Send a stop condition to the backend. */ i2c_slave_event(slave, I2C_SLAVE_STOP, &value); - /* Handle the actual transfer. */ - /* Set the number of bytes to write to master. */ write_size = (byte_cnt - 1) & 0x7f; @@ -1949,38 +1917,44 @@ static int mlxbf_smbus_irq_send(struct mlxbf_i2c_priv *priv, u8 recv_bytes) */ mlxbf_smbus_slave_wait_for_idle(priv, MLXBF_I2C_SMBUS_TIMEOUT); +clear_csr: /* Release the Slave GW. */ writel(0x0, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES); writel(0x0, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_PEC); writel(0x1, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_READY); - return 0; + return ret; } -/* Receive bytes from 'external' smbus master. */ -static int mlxbf_smbus_irq_recv(struct mlxbf_i2c_priv *priv, u8 recv_bytes) +/* + * Receive bytes from 'external' smbus master. This function is executed when + * an external smbus master wants to write data to the BlueField. + */ +static int mlxbf_i2c_irq_recv(struct mlxbf_i2c_priv *priv, u8 recv_bytes) { u8 data_desc[MLXBF_I2C_SLAVE_DATA_DESC_SIZE] = { 0 }; - struct i2c_client *slave = priv->slave; + struct i2c_client *slave; u8 value, byte, addr; int ret = 0; - if (!slave) - return -EINVAL; - /* Read data from Slave GW data descriptor. */ mlxbf_i2c_smbus_read_data(priv, data_desc, recv_bytes, MLXBF_I2C_SLAVE_DATA_DESC_ADDR); - - /* Check whether its our slave address. */ addr = data_desc[0] >> 1; - if (slave->addr != addr) - return -EINVAL; /* - * Notify the slave backend; another I2C master wants to write data - * to us. This event is sent once the slave address and the write bit - * is detected. + * Check if the slave address received in the data descriptor register + * matches any of the slave addresses registered. + */ + slave = mlxbf_i2c_get_slave_from_addr(priv, addr); + if (!slave) { + ret = -EINVAL; + goto clear_csr; + } + + /* + * Notify the slave backend that an smbus master wants to write data + * to the BlueField. */ i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value); @@ -1993,9 +1967,13 @@ static int mlxbf_smbus_irq_recv(struct mlxbf_i2c_priv *priv, u8 recv_bytes) break; } - /* Send a stop condition to the backend. */ + /* + * Send a stop event to the slave backend, to signal + * the end of the write transactions. + */ i2c_slave_event(slave, I2C_SLAVE_STOP, &value); +clear_csr: /* Release the Slave GW. */ writel(0x0, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES); writel(0x0, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_PEC); @@ -2004,7 +1982,7 @@ static int mlxbf_smbus_irq_recv(struct mlxbf_i2c_priv *priv, u8 recv_bytes) return ret; } -static irqreturn_t mlxbf_smbus_irq(int irq, void *ptr) +static irqreturn_t mlxbf_i2c_irq(int irq, void *ptr) { struct mlxbf_i2c_priv *priv = ptr; bool read, write, irq_is_set; @@ -2052,9 +2030,9 @@ static irqreturn_t mlxbf_smbus_irq(int irq, void *ptr) MLXBF_I2C_SLAVE_DATA_DESC_SIZE : recv_bytes; if (read) - mlxbf_smbus_irq_send(priv, recv_bytes); + mlxbf_i2c_irq_send(priv, recv_bytes); else - mlxbf_smbus_irq_recv(priv, recv_bytes); + mlxbf_i2c_irq_recv(priv, recv_bytes); return IRQ_HANDLED; } @@ -2149,23 +2127,21 @@ static s32 mlxbf_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, static int mlxbf_i2c_reg_slave(struct i2c_client *slave) { struct mlxbf_i2c_priv *priv = i2c_get_adapdata(slave->adapter); + struct device *dev = &slave->dev; int ret; - if (priv->slave) - return -EBUSY; - /* * Do not support ten bit chip address and do not use Packet Error * Checking (PEC). */ - if (slave->flags & (I2C_CLIENT_TEN | I2C_CLIENT_PEC)) + if (slave->flags & (I2C_CLIENT_TEN | I2C_CLIENT_PEC)) { + dev_err(dev, "SMBus PEC and 10 bit address not supported\n"); return -EAFNOSUPPORT; + } - ret = mlxbf_slave_enable(priv, slave->addr); - if (ret < 0) - return ret; - - priv->slave = slave; + ret = mlxbf_i2c_slave_enable(priv, slave); + if (ret) + dev_err(dev, "Surpassed max number of registered slaves allowed\n"); return 0; } @@ -2173,18 +2149,19 @@ static int mlxbf_i2c_reg_slave(struct i2c_client *slave) static int mlxbf_i2c_unreg_slave(struct i2c_client *slave) { struct mlxbf_i2c_priv *priv = i2c_get_adapdata(slave->adapter); + struct device *dev = &slave->dev; int ret; - WARN_ON(!priv->slave); - - /* Unregister slave, i.e. disable the slave address in hardware. */ - ret = mlxbf_slave_disable(priv); - if (ret < 0) - return ret; - - priv->slave = NULL; + /* + * Unregister slave by: + * 1) Disabling the slave address in hardware + * 2) Freeing priv->slave at the corresponding index + */ + ret = mlxbf_i2c_slave_disable(priv, slave->addr); + if (ret) + dev_err(dev, "Unable to find slave 0x%x\n", slave->addr); - return 0; + return ret; } static u32 mlxbf_i2c_functionality(struct i2c_adapter *adap) @@ -2392,7 +2369,7 @@ static int mlxbf_i2c_probe(struct platform_device *pdev) irq = platform_get_irq(pdev, 0); if (irq < 0) return irq; - ret = devm_request_irq(dev, irq, mlxbf_smbus_irq, + ret = devm_request_irq(dev, irq, mlxbf_i2c_irq, IRQF_SHARED | IRQF_PROBE_SHARED, dev_name(dev), priv); if (ret < 0) { @@ -2487,4 +2464,5 @@ module_exit(mlxbf_i2c_exit); MODULE_DESCRIPTION("Mellanox BlueField I2C bus driver"); MODULE_AUTHOR("Khalil Blaiech <kblaiech@nvidia.com>"); +MODULE_AUTHOR("Asmaa Mnebhi <asmaa@nvidia.com>"); MODULE_LICENSE("GPL v2"); |