[RFC PATCH dev-5.1 5/6] i2c: aspeed: add buffer mode transfer support
Jae Hyun Yoo
jae.hyun.yoo at linux.intel.com
Fri Jun 21 05:49:21 AEST 2019
Byte mode currently this driver uses makes lots of interrupt call
which isn't good for performance and it makes the driver very
timing sensitive. To improve performance of the driver, this commit
adds buffer mode transfer support which uses I2C SRAM buffer
instead of using a single byte buffer.
Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo at linux.intel.com>
---
drivers/i2c/busses/i2c-aspeed.c | 252 ++++++++++++++++++++++++++++----
1 file changed, 225 insertions(+), 27 deletions(-)
diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
index cde9dbac2d46..9e6f71de5c7e 100644
--- a/drivers/i2c/busses/i2c-aspeed.c
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -10,6 +10,7 @@
* published by the Free Software Foundation.
*/
+#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/err.h>
@@ -38,6 +39,7 @@
#define ASPEED_I2C_INTR_STS_REG 0x10
#define ASPEED_I2C_CMD_REG 0x14
#define ASPEED_I2C_DEV_ADDR_REG 0x18
+#define ASPEED_I2C_BUF_CTRL_REG 0x1c
#define ASPEED_I2C_BYTE_BUF_REG 0x20
/* Global Register Definition */
@@ -46,6 +48,7 @@
/* Device Register Definition */
/* 0x00 : I2CD Function Control Register */
+#define ASPEED_I2CD_BUFFER_PAGE_SEL_MASK GENMASK(22, 20)
#define ASPEED_I2CD_MULTI_MASTER_DIS BIT(15)
#define ASPEED_I2CD_SDA_DRIVE_1T_EN BIT(8)
#define ASPEED_I2CD_M_SDA_DRIVE_1T_EN BIT(7)
@@ -105,6 +108,8 @@
#define ASPEED_I2CD_BUS_RECOVER_CMD BIT(11)
/* Command Bit */
+#define ASPEED_I2CD_RX_BUFF_ENABLE BIT(7)
+#define ASPEED_I2CD_TX_BUFF_ENABLE BIT(6)
#define ASPEED_I2CD_M_STOP_CMD BIT(5)
#define ASPEED_I2CD_M_S_RX_CMD_LAST BIT(4)
#define ASPEED_I2CD_M_RX_CMD BIT(3)
@@ -115,6 +120,13 @@
/* 0x18 : I2CD Slave Device Address Register */
#define ASPEED_I2CD_DEV_ADDR_MASK GENMASK(6, 0)
+/* 0x1c : I2CD Buffer Control Register */
+/* Use 8-bits or 6-bits wide bit fileds to support both AST2400 and AST2500 */
+#define ASPEED_I2CD_BUF_RX_COUNT_MASK GENMASK(31, 24)
+#define ASPEED_I2CD_BUF_RX_SIZE_MASK GENMASK(23, 16)
+#define ASPEED_I2CD_BUF_TX_COUNT_MASK GENMASK(15, 8)
+#define ASPEED_I2CD_BUF_OFFSET_MASK GENMASK(5, 0)
+
enum aspeed_i2c_master_state {
ASPEED_I2C_MASTER_INACTIVE,
ASPEED_I2C_MASTER_PENDING,
@@ -160,6 +172,11 @@ struct aspeed_i2c_bus {
int master_xfer_result;
/* Multi-master */
bool multi_master;
+ /* Buffer mode */
+ void __iomem *buf_base;
+ size_t buf_size;
+ u8 buf_offset;
+ u8 buf_page;
#if IS_ENABLED(CONFIG_I2C_SLAVE)
struct i2c_client *slave;
enum aspeed_i2c_slave_state slave_state;
@@ -241,6 +258,7 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
{
u32 command, irq_handled = 0;
struct i2c_client *slave = bus->slave;
+ int i, len;
u8 value;
if (!slave)
@@ -263,7 +281,11 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
/* Slave was sent something. */
if (irq_status & ASPEED_I2CD_INTR_RX_DONE) {
- value = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8;
+ if (bus->buf_base &&
+ bus->slave_state == ASPEED_I2C_SLAVE_WRITE_RECEIVED)
+ value = readb(bus->buf_base);
+ else
+ value = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8;
/* Handle address frame. */
if (bus->slave_state == ASPEED_I2C_SLAVE_START) {
if (value & 0x1)
@@ -278,6 +300,18 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
/* Slave was asked to stop. */
if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
+ if (bus->buf_base &&
+ bus->slave_state == ASPEED_I2C_SLAVE_WRITE_RECEIVED) {
+ len = FIELD_GET(ASPEED_I2CD_BUF_RX_COUNT_MASK,
+ readl(bus->base +
+ ASPEED_I2C_BUF_CTRL_REG));
+ for (i = 0; i < len; i++) {
+ value = readb(bus->buf_base + i);
+ i2c_slave_event(slave,
+ I2C_SLAVE_WRITE_RECEIVED,
+ &value);
+ }
+ }
irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
bus->slave_state = ASPEED_I2C_SLAVE_STOP;
}
@@ -310,9 +344,36 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
case ASPEED_I2C_SLAVE_WRITE_REQUESTED:
bus->slave_state = ASPEED_I2C_SLAVE_WRITE_RECEIVED;
i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+ if (bus->buf_base) {
+ writel(FIELD_PREP(ASPEED_I2CD_BUF_RX_SIZE_MASK,
+ bus->buf_size - 1) |
+ FIELD_PREP(ASPEED_I2CD_BUF_OFFSET_MASK,
+ bus->buf_offset),
+ bus->base + ASPEED_I2C_BUF_CTRL_REG);
+ writel(ASPEED_I2CD_RX_BUFF_ENABLE,
+ bus->base + ASPEED_I2C_CMD_REG);
+ }
break;
case ASPEED_I2C_SLAVE_WRITE_RECEIVED:
i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
+ if (bus->buf_base) {
+ len = FIELD_GET(ASPEED_I2CD_BUF_RX_COUNT_MASK,
+ readl(bus->base +
+ ASPEED_I2C_BUF_CTRL_REG));
+ for (i = 1; i < len; i++) {
+ value = readb(bus->buf_base + i);
+ i2c_slave_event(slave,
+ I2C_SLAVE_WRITE_RECEIVED,
+ &value);
+ }
+ writel(FIELD_PREP(ASPEED_I2CD_BUF_RX_SIZE_MASK,
+ bus->buf_size - 1) |
+ FIELD_PREP(ASPEED_I2CD_BUF_OFFSET_MASK,
+ bus->buf_offset),
+ bus->base + ASPEED_I2C_BUF_CTRL_REG);
+ writel(ASPEED_I2CD_RX_BUFF_ENABLE,
+ bus->base + ASPEED_I2C_CMD_REG);
+ }
break;
case ASPEED_I2C_SLAVE_STOP:
i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
@@ -338,6 +399,8 @@ static void aspeed_i2c_do_start(struct aspeed_i2c_bus *bus)
u32 command = ASPEED_I2CD_M_START_CMD | ASPEED_I2CD_M_TX_CMD;
struct i2c_msg *msg = &bus->msgs[bus->msgs_index];
u8 slave_addr = i2c_8bit_addr_from_msg(msg);
+ u8 wbuf[4];
+ int len;
#if IS_ENABLED(CONFIG_I2C_SLAVE)
/*
@@ -356,12 +419,66 @@ static void aspeed_i2c_do_start(struct aspeed_i2c_bus *bus)
if (msg->flags & I2C_M_RD) {
command |= ASPEED_I2CD_M_RX_CMD;
- /* Need to let the hardware know to NACK after RX. */
- if (msg->len == 1 && !(msg->flags & I2C_M_RECV_LEN))
- command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
+
+ if (bus->buf_base && !(msg->flags & I2C_M_RECV_LEN)) {
+ command |= ASPEED_I2CD_RX_BUFF_ENABLE;
+
+ if (msg->len > bus->buf_size) {
+ len = bus->buf_size;
+ } else {
+ len = msg->len;
+ command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
+ }
+
+ writel(FIELD_PREP(ASPEED_I2CD_BUF_RX_SIZE_MASK,
+ len - 1) |
+ FIELD_PREP(ASPEED_I2CD_BUF_OFFSET_MASK,
+ bus->buf_offset),
+ bus->base + ASPEED_I2C_BUF_CTRL_REG);
+ } else {
+ /* Need to let the hardware know to NACK after RX. */
+ if (msg->len == 1 && !(msg->flags & I2C_M_RECV_LEN))
+ command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
+ }
+ } else {
+ if (bus->buf_base) {
+ int i;
+
+ command |= ASPEED_I2CD_TX_BUFF_ENABLE;
+
+ if (msg->len + 1 > bus->buf_size)
+ len = bus->buf_size;
+ else
+ len = msg->len + 1;
+
+ /*
+ * Yeah, it looks clumsy but byte writings on a remapped
+ * I2C SRAM cause corruptions so use this way to make
+ * dword writings.
+ */
+ wbuf[0] = slave_addr;
+ for (i = 1; i < len; i++) {
+ wbuf[i % 4] = msg->buf[i - 1];
+ if (i % 4 == 3)
+ writel(*(u32 *)wbuf,
+ bus->buf_base + i - 3);
+ }
+ if (--i % 4 != 3)
+ writel(*(u32 *)wbuf,
+ bus->buf_base + i - (i % 4));
+
+ bus->buf_index = len - 1;
+
+ writel(FIELD_PREP(ASPEED_I2CD_BUF_TX_COUNT_MASK,
+ len - 1) |
+ FIELD_PREP(ASPEED_I2CD_BUF_OFFSET_MASK,
+ bus->buf_offset),
+ bus->base + ASPEED_I2C_BUF_CTRL_REG);
+ }
}
- writel(slave_addr, bus->base + ASPEED_I2C_BYTE_BUF_REG);
+ if (!(command & ASPEED_I2CD_TX_BUFF_ENABLE))
+ writel(slave_addr, bus->base + ASPEED_I2C_BYTE_BUF_REG);
writel(command, bus->base + ASPEED_I2C_CMD_REG);
}
@@ -401,7 +518,7 @@ static u32 aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
u32 irq_handled = 0, command = 0;
struct i2c_msg *msg;
u8 recv_byte;
- int ret;
+ int ret, len;
if (irq_status & ASPEED_I2CD_INTR_BUS_RECOVER_DONE) {
bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
@@ -514,11 +631,43 @@ static u32 aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
/* fall through */
case ASPEED_I2C_MASTER_TX_FIRST:
if (bus->buf_index < msg->len) {
+ command = ASPEED_I2CD_M_TX_CMD;
+
+ if (bus->buf_base) {
+ u8 wbuf[4];
+ int i;
+
+ command |= ASPEED_I2CD_TX_BUFF_ENABLE;
+
+ if (msg->len - bus->buf_index > bus->buf_size)
+ len = bus->buf_size;
+ else
+ len = msg->len - bus->buf_index;
+
+ for (i = 0; i < len; i++) {
+ wbuf[i % 4] = msg->buf[bus->buf_index
+ + i];
+ if (i % 4 == 3)
+ writel(*(u32 *)wbuf,
+ bus->buf_base + i - 3);
+ }
+ if (--i % 4 != 3)
+ writel(*(u32 *)wbuf,
+ bus->buf_base + i - (i % 4));
+
+ bus->buf_index += len;
+
+ writel(FIELD_PREP(ASPEED_I2CD_BUF_TX_COUNT_MASK,
+ len - 1) |
+ FIELD_PREP(ASPEED_I2CD_BUF_OFFSET_MASK,
+ bus->buf_offset),
+ bus->base + ASPEED_I2C_BUF_CTRL_REG);
+ } else {
+ writel(msg->buf[bus->buf_index++],
+ bus->base + ASPEED_I2C_BYTE_BUF_REG);
+ }
+ writel(command, bus->base + ASPEED_I2C_CMD_REG);
bus->master_state = ASPEED_I2C_MASTER_TX;
- writel(msg->buf[bus->buf_index++],
- bus->base + ASPEED_I2C_BYTE_BUF_REG);
- writel(ASPEED_I2CD_M_TX_CMD,
- bus->base + ASPEED_I2C_CMD_REG);
} else {
aspeed_i2c_next_msg_or_stop(bus);
}
@@ -535,25 +684,56 @@ static u32 aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
}
irq_handled |= ASPEED_I2CD_INTR_RX_DONE;
- recv_byte = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8;
- msg->buf[bus->buf_index++] = recv_byte;
-
- if (msg->flags & I2C_M_RECV_LEN) {
- if (unlikely(recv_byte > I2C_SMBUS_BLOCK_MAX)) {
- bus->cmd_err = -EPROTO;
- aspeed_i2c_do_stop(bus);
- goto out_no_complete;
+ if (bus->buf_base && !(msg->flags & I2C_M_RECV_LEN)) {
+ len = FIELD_GET(ASPEED_I2CD_BUF_RX_COUNT_MASK,
+ readl(bus->base +
+ ASPEED_I2C_BUF_CTRL_REG));
+ memcpy_fromio(msg->buf + bus->buf_index,
+ bus->buf_base, len);
+ bus->buf_index += len;
+ } else {
+ recv_byte = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG)
+ >> 8;
+ msg->buf[bus->buf_index++] = recv_byte;
+
+ if (msg->flags & I2C_M_RECV_LEN) {
+ if (unlikely(recv_byte > I2C_SMBUS_BLOCK_MAX)) {
+ bus->cmd_err = -EPROTO;
+ aspeed_i2c_do_stop(bus);
+ goto out_no_complete;
+ }
+ msg->len = recv_byte +
+ ((msg->flags & I2C_CLIENT_PEC) ?
+ 2 : 1);
+ msg->flags &= ~I2C_M_RECV_LEN;
}
- msg->len = recv_byte +
- ((msg->flags & I2C_CLIENT_PEC) ? 2 : 1);
- msg->flags &= ~I2C_M_RECV_LEN;
}
if (bus->buf_index < msg->len) {
- bus->master_state = ASPEED_I2C_MASTER_RX;
command = ASPEED_I2CD_M_RX_CMD;
- if (bus->buf_index + 1 == msg->len)
- command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
+ bus->master_state = ASPEED_I2C_MASTER_RX;
+ if (bus->buf_base) {
+ command |= ASPEED_I2CD_RX_BUFF_ENABLE;
+
+ if (msg->len - bus->buf_index >
+ bus->buf_size) {
+ len = bus->buf_size;
+ } else {
+ len = msg->len - bus->buf_index;
+ command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
+ }
+
+ writel(FIELD_PREP(ASPEED_I2CD_BUF_RX_SIZE_MASK,
+ len - 1) |
+ FIELD_PREP(ASPEED_I2CD_BUF_TX_COUNT_MASK,
+ 0) |
+ FIELD_PREP(ASPEED_I2CD_BUF_OFFSET_MASK,
+ bus->buf_offset),
+ bus->base + ASPEED_I2C_BUF_CTRL_REG);
+ } else {
+ if (bus->buf_index + 1 == msg->len)
+ command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
+ }
writel(command, bus->base + ASPEED_I2C_CMD_REG);
} else {
aspeed_i2c_next_msg_or_stop(bus);
@@ -893,6 +1073,9 @@ static int aspeed_i2c_init(struct aspeed_i2c_bus *bus,
if (ret < 0)
return ret;
+ fun_ctrl_reg |= FIELD_PREP(ASPEED_I2CD_BUFFER_PAGE_SEL_MASK,
+ bus->buf_page);
+
if (of_property_read_bool(pdev->dev.of_node, "multi-master"))
bus->multi_master = true;
else
@@ -958,7 +1141,7 @@ static int aspeed_i2c_probe_bus(struct platform_device *pdev)
if (!bus)
return -ENOMEM;
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "bus-regs");
bus->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(bus->base))
return PTR_ERR(bus->base);
@@ -993,6 +1176,21 @@ static int aspeed_i2c_probe_bus(struct platform_device *pdev)
bus->get_clk_reg_val = (u32 (*)(struct device *, u32))
match->data;
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "buf");
+ bus->buf_base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(bus->buf_base) || resource_size(res) < 2) {
+ bus->buf_base = NULL;
+ } else {
+ bus->buf_size = resource_size(res);
+ if (of_device_is_compatible(pdev->dev.of_node,
+ "aspeed,ast2400-i2c-bus")) {
+ bus->buf_page = ((res->start >> 8) &
+ GENMASK(3, 0)) - 8;
+ bus->buf_offset = (res->start >> 2) &
+ ASPEED_I2CD_BUF_OFFSET_MASK;
+ }
+ }
+
/* Initialize the I2C adapter */
spin_lock_init(&bus->lock);
init_completion(&bus->cmd_complete);
@@ -1029,8 +1227,8 @@ static int aspeed_i2c_probe_bus(struct platform_device *pdev)
platform_set_drvdata(pdev, bus);
- dev_info(bus->dev, "i2c bus %d registered, irq %d\n",
- bus->adap.nr, irq);
+ dev_info(bus->dev, "i2c bus %d registered (%s mode), irq %d\n",
+ bus->adap.nr, bus->buf_base ? "buffer" : "byte", irq);
return 0;
}
--
2.22.0
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