2016-10-31 06:51:33

by Tin Huynh

[permalink] [raw]
Subject: [PATCH v3] i2c: designware: Implement support for SMBus block read and write

From: Tin Huynh <[email protected]>

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 <[email protected]>
---
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 | 45 +++++++++++++++++++++++++--
drivers/i2c/busses/i2c-designware-pcidrv.c | 1 +
drivers/i2c/busses/i2c-designware-platdrv.c | 1 +
3 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index 1fe93c4..69c7ab8 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -543,6 +543,7 @@ 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 +589,15 @@ 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 set 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 +622,12 @@ 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 +648,25 @@ 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) ? len + 2 : len + 1;
+ dev->tx_buf_len = len > dev->rx_outstanding ?
+ len - dev->rx_outstanding : 0;
+ 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 +691,14 @@ 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


2016-10-31 12:05:16

by Mika Westerberg

[permalink] [raw]
Subject: Re: [PATCH v3] i2c: designware: Implement support for SMBus block read and write

On Mon, Oct 31, 2016 at 01:51:17PM +0700, [email protected] wrote:
> From: Tin Huynh <[email protected]>
>
> 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 <[email protected]>

Looks good to me,

Reviewed-by: Mika Westerberg <[email protected]>

2016-10-31 13:23:12

by Jarkko Nikula

[permalink] [raw]
Subject: Re: [PATCH v3] i2c: designware: Implement support for SMBus block read and write

On 10/31/2016 02:05 PM, Mika Westerberg wrote:
> On Mon, Oct 31, 2016 at 01:51:17PM +0700, [email protected] wrote:
>> From: Tin Huynh <[email protected]>
>>
>> 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 <[email protected]>
>
> Looks good to me,
>
> Reviewed-by: Mika Westerberg <[email protected]>
>
Acked-by: Jarkko Nikula <[email protected]>

2016-11-07 14:11:10

by Andy Shevchenko

[permalink] [raw]
Subject: Re: [PATCH v3] i2c: designware: Implement support for SMBus block read and write

On Mon, 2016-10-31 at 13:51 +0700, [email protected] wrote:
> From: Tin Huynh <[email protected]>
>
> 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.

My comments below.


> @@ -543,6 +543,7 @@ 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;

+ empty line.

>   /*
>    * if target address has changed, we need to
>    * reprogram the target address in the i2c

> @@ -588,8 +589,15 @@ 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 set the buffer length of

set -> sets

> +  * 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.
> +  */
>

> @@ -635,6 +648,25 @@ 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

Add dot to the end, please.

> +  */
> + len = (flags & I2C_CLIENT_PEC) ? len + 2 : len + 1;

len += flags & I2C_CLIENT_PEC ? 2 : 1;

> + dev->tx_buf_len = len > dev->rx_outstanding ?
> + len - dev->rx_outstanding : 0;

Can be len more than twice longer as rx_outstanding?

Would it be better to write as
tx_buf_len = len - min(len, 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 +691,14 @@ 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;

+ empty line.

> + *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) {

Is it my mail client or indentation is wrong?

> + len = i2c_dw_recv_len(dev, *buf);
> + }
> + buf++;
>   dev->rx_outstanding--;
>   }

--
Andy Shevchenko <[email protected]>
Intel Finland Oy