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Message-Id: <1478746593-10905-1-git-send-email-tnhuynh@apm.com>
Date: Thu, 10 Nov 2016 09:56:33 +0700
From: tnhuynh@....com
To: Jarkko Nikula <jarkko.nikula@...ux.intel.com>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Mika Westerberg <mika.westerberg@...ux.intel.com>,
Wolfram Sang <wsa@...-dreams.de>, linux-i2c@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Loc Ho <lho@....com>, Thang Nguyen <tqnguyen@....com>,
Phong Vo <pvo@....com>, patches@....com,
Tin Huynh <tnhuynh@....com>
Subject: [PATCH v4] i2c: designware: Implement support for SMBus block read and write
From: Tin Huynh <tnhuynh@....com>
Free and Open IPMI use SMBUS BLOCK Read/Write to support SSIF protocol.
However, I2C Designware Core Driver doesn't handle the case at the moment.
The below patch supports this feature.
Signed-off-by: Tin Huynh <tnhuynh@....com>
---
Change from V3:
- Correct coding conventions
- Make clean
Change from V2:
- Change subject of email
- Add a helper function to handle
length byte receiving
Change from V1:
- Remove empty lines
- Add flags variable to make clean code
- Change DW_DEFAULT_FUNCTIONALITY
in i2c-designware-pcidrv.c
---
drivers/i2c/busses/i2c-designware-core.c | 46 +++++++++++++++++++++++++--
drivers/i2c/busses/i2c-designware-pcidrv.c | 1 +
drivers/i2c/busses/i2c-designware-platdrv.c | 1 +
3 files changed, 45 insertions(+), 3 deletions(-)
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index 1fe93c4..c91d1b4 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -543,6 +543,8 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
intr_mask = DW_IC_INTR_DEFAULT_MASK;
for (; dev->msg_write_idx < dev->msgs_num; dev->msg_write_idx++) {
+ u32 flags = msgs[dev->msg_write_idx].flags;
+
/*
* if target address has changed, we need to
* reprogram the target address in the i2c
@@ -588,8 +590,15 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
* detected from the registers so we set it always
* when writing/reading the last byte.
*/
+
+ /*
+ * i2c-core.c always sets the buffer length of
+ * I2C_FUNC_SMBUS_BLOCK_DATA to 1. The length will
+ * be adjusted when receiving the first byte.
+ * Thus we can't stop the transaction here.
+ */
if (dev->msg_write_idx == dev->msgs_num - 1 &&
- buf_len == 1)
+ buf_len == 1 && !(flags & I2C_M_RECV_LEN))
cmd |= BIT(9);
if (need_restart) {
@@ -614,7 +623,12 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
dev->tx_buf = buf;
dev->tx_buf_len = buf_len;
- if (buf_len > 0) {
+ /*
+ * Because we don't know the buffer length in the
+ * I2C_FUNC_SMBUS_BLOCK_DATA case, we can't stop
+ * the transaction here.
+ */
+ if (buf_len > 0 || flags & I2C_M_RECV_LEN) {
/* more bytes to be written */
dev->status |= STATUS_WRITE_IN_PROGRESS;
break;
@@ -635,6 +649,24 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
dw_writel(dev, intr_mask, DW_IC_INTR_MASK);
}
+static u8
+i2c_dw_recv_len(struct dw_i2c_dev *dev, u8 len)
+{
+ struct i2c_msg *msgs = dev->msgs;
+ u32 flags = msgs[dev->msg_read_idx].flags;
+
+ /*
+ * Adjust the buffer length and mask the flag
+ * after receiving the first byte.
+ */
+ len += (flags & I2C_CLIENT_PEC) ? 2 : 1;
+ dev->tx_buf_len = len - min_t(u8, len, dev->rx_outstanding);
+ msgs[dev->msg_read_idx].len = len;
+ msgs[dev->msg_read_idx].flags &= ~I2C_M_RECV_LEN;
+
+ return len;
+}
+
static void
i2c_dw_read(struct dw_i2c_dev *dev)
{
@@ -659,7 +691,15 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
rx_valid = dw_readl(dev, DW_IC_RXFLR);
for (; len > 0 && rx_valid > 0; len--, rx_valid--) {
- *buf++ = dw_readl(dev, DW_IC_DATA_CMD);
+ u32 flags = msgs[dev->msg_read_idx].flags;
+
+ *buf = dw_readl(dev, DW_IC_DATA_CMD);
+ /* Ensure length byte is a valid value */
+ if (flags & I2C_M_RECV_LEN &&
+ *buf <= I2C_SMBUS_BLOCK_MAX && *buf > 0) {
+ len = i2c_dw_recv_len(dev, *buf);
+ }
+ buf++;
dev->rx_outstanding--;
}
diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c b/drivers/i2c/busses/i2c-designware-pcidrv.c
index 96f8230..8ffe2da 100644
--- a/drivers/i2c/busses/i2c-designware-pcidrv.c
+++ b/drivers/i2c/busses/i2c-designware-pcidrv.c
@@ -75,6 +75,7 @@ struct dw_pci_controller {
I2C_FUNC_SMBUS_BYTE | \
I2C_FUNC_SMBUS_BYTE_DATA | \
I2C_FUNC_SMBUS_WORD_DATA | \
+ I2C_FUNC_SMBUS_BLOCK_DATA | \
I2C_FUNC_SMBUS_I2C_BLOCK)
/* Merrifield HCNT/LCNT/SDA hold time */
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 0b42a12..886fb62 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -220,6 +220,7 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
I2C_FUNC_SMBUS_BYTE |
I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_WORD_DATA |
+ I2C_FUNC_SMBUS_BLOCK_DATA |
I2C_FUNC_SMBUS_I2C_BLOCK;
dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
--
1.7.1
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