Re: [PATCH 1/2] i3c: Add basic HDR support
From: Mukesh Kumar Savaliya
Date: Mon Feb 03 2025 - 00:23:32 EST
Hi Joshua,
On 2/3/2025 8:02 AM, Joshua Yeong wrote:
Hi Mukesh and Frank,
On 02-Feb-2025 1:54 AM, Mukesh Kumar Savaliya wrote:
Hi Frank,
On 1/30/2025 1:35 AM, Frank Li wrote:
I3C HDR requires enter/exit patterns during each I3C transfer. Add a new
API i3c_device_do_priv_xfers_mode(). The existing
i3c_device_do_priv_xfers() now calls i3c_device_do_priv_xfers_mode(I3C_SDR)
to maintain backward compatibility.
Introduce a 'cmd' field in 'struct i3c_priv_xfer', using an anonymous union
with 'rnw' since HDR mode relies on read/write commands instead of the
'rnw' bit in the address as in SDR mode.
Add a priv_xfers_mode callback for I3C master drivers. If priv_xfers_mode
is not implemented, fallback to SDR mode using the existing priv_xfers
callback.
Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
Why not add hdr mode in struct i3c_priv_xfer because mode can't be mixed in
one i3c transfer. for example, can't send a HDR follow one SDR between
START and STOP.
Is it wise to add two function inside main funcion and separate SDR vs HDR ? so we don't need to change current function arguments.
I think the 'private transfers' are limited to SDR communications,
would it be better if we have a different interface/naming for hdr transfers?
i3c_priv_xfer should be treat as whole i3c transactions. If user want send
HDR follow SDR, should be call i3c_device_do_priv_xfers_mode() twice,
instead put into a big i3c_priv_xfer[n].
---
drivers/i3c/device.c | 19 +++++++++++++------
drivers/i3c/internals.h | 2 +-
drivers/i3c/master.c | 8 +++++++-
include/linux/i3c/device.h | 12 +++++++++++-
include/linux/i3c/master.h | 3 +++
5 files changed, 35 insertions(+), 9 deletions(-)
diff --git a/drivers/i3c/device.c b/drivers/i3c/device.c
index e80e487569146..e3db3a6a9e4f6 100644
--- a/drivers/i3c/device.c
+++ b/drivers/i3c/device.c
@@ -15,12 +15,13 @@
#include "internals.h"
/**
- * i3c_device_do_priv_xfers() - do I3C SDR private transfers directed to a
- * specific device
+ * i3c_device_do_priv_xfers_mode() - do I3C SDR private transfers directed to a
+ * specific device
*
* @dev: device with which the transfers should be done
* @xfers: array of transfers
* @nxfers: number of transfers
+ * @mode: transfer mode
*
* Initiate one or several private SDR transfers with @dev.
*
@@ -32,9 +33,9 @@
* driver needs to resend the 'xfers' some time later.
* See I3C spec ver 1.1.1 09-Jun-2021. Section: 5.1.2.2.3.
*/
-int i3c_device_do_priv_xfers(struct i3c_device *dev,
- struct i3c_priv_xfer *xfers,
- int nxfers)
+int i3c_device_do_priv_xfers_mode(struct i3c_device *dev,
+ struct i3c_priv_xfer *xfers,
+ int nxfers, enum i3c_hdr_mode mode)
why can't we pass mode as another structure member inside struct i3c_priv_xfer ? Adding function agrument parameter impacts existing drivers.
Yes, that would be fine too as we can clearly differentiate by
inteface/hook up name.
{
int ret, i;
@@ -47,11 +48,17 @@ int i3c_device_do_priv_xfers(struct i3c_device *dev,
}
i3c_bus_normaluse_lock(dev->bus);
- ret = i3c_dev_do_priv_xfers_locked(dev->desc, xfers, nxfers);
+ ret = i3c_dev_do_priv_xfers_locked(dev->desc, xfers, nxfers, mode);
i3c_bus_normaluse_unlock(dev->bus);
return ret;
}
+EXPORT_SYMBOL_GPL(i3c_device_do_priv_xfers_mode);
+
+int i3c_device_do_priv_xfers(struct i3c_device *dev, struct i3c_priv_xfer *xfers, int nxfers)
+{
+ return i3c_device_do_priv_xfers_mode(dev, xfers, nxfers, I3C_SDR);
+}
EXPORT_SYMBOL_GPL(i3c_device_do_priv_xfers);
/**
diff --git a/drivers/i3c/internals.h b/drivers/i3c/internals.h
index 433f6088b7cec..553edc9846ac0 100644
--- a/drivers/i3c/internals.h
+++ b/drivers/i3c/internals.h
@@ -16,7 +16,7 @@ void i3c_bus_normaluse_unlock(struct i3c_bus *bus);
int i3c_dev_setdasa_locked(struct i3c_dev_desc *dev);
int i3c_dev_do_priv_xfers_locked(struct i3c_dev_desc *dev,
struct i3c_priv_xfer *xfers,
- int nxfers);
+ int nxfers, enum i3c_hdr_mode mode);
int i3c_dev_disable_ibi_locked(struct i3c_dev_desc *dev);
int i3c_dev_enable_ibi_locked(struct i3c_dev_desc *dev);
int i3c_dev_request_ibi_locked(struct i3c_dev_desc *dev,
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index d5dc4180afbcf..67aaba0a38db2 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -2945,7 +2945,7 @@ int i3c_dev_setdasa_locked(struct i3c_dev_desc *dev)
int i3c_dev_do_priv_xfers_locked(struct i3c_dev_desc *dev,
struct i3c_priv_xfer *xfers,
- int nxfers)
+ int nxfers, enum i3c_hdr_mode mode)
{
struct i3c_master_controller *master;
@@ -2956,9 +2956,15 @@ int i3c_dev_do_priv_xfers_locked(struct i3c_dev_desc *dev,
if (!master || !xfers)
return -EINVAL;
+ if (master->ops->priv_xfers_mode)
+ return master->ops->priv_xfers_mode(dev, xfers, nxfers, mode);
+
if (!master->ops->priv_xfers)
return -ENOTSUPP;
+ if (mode != I3C_SDR)
+ return -EINVAL;
+
return master->ops->priv_xfers(dev, xfers, nxfers);
}
diff --git a/include/linux/i3c/device.h b/include/linux/i3c/device.h
index b674f64d0822e..7ce70d0967e27 100644
--- a/include/linux/i3c/device.h
+++ b/include/linux/i3c/device.h
@@ -40,11 +40,13 @@ enum i3c_error_code {
/**
* enum i3c_hdr_mode - HDR mode ids
+ * @I3C_SDR: SDR mode (NOT HDR mode)
* @I3C_HDR_DDR: DDR mode
* @I3C_HDR_TSP: TSP mode
* @I3C_HDR_TSL: TSL mode
*/
enum i3c_hdr_mode {
+ I3C_SDR,
I3C_HDR_DDR,
I3C_HDR_TSP,
I3C_HDR_TSL,
@@ -53,6 +55,7 @@ enum i3c_hdr_mode {
/**
* struct i3c_priv_xfer - I3C SDR private transfer
* @rnw: encodes the transfer direction. true for a read, false for a write
+ * @cmd: Read/Write command in HDR mode, read: 0x80 - 0xff, write: 0x00 - 0x7f
* @len: transfer length in bytes of the transfer
* @actual_len: actual length in bytes are transferred by the controller
* @data: input/output buffer
@@ -61,7 +64,10 @@ enum i3c_hdr_mode {
* @err: I3C error code
*/
struct i3c_priv_xfer {
- u8 rnw;
+ union {
+ u8 rnw;
+ u8 cmd;
+ };
u16 len;
u16 actual_len;
union {
@@ -301,6 +307,10 @@ int i3c_device_do_priv_xfers(struct i3c_device *dev,
struct i3c_priv_xfer *xfers,
int nxfers);
+int i3c_device_do_priv_xfers_mode(struct i3c_device *dev,
+ struct i3c_priv_xfer *xfers,
+ int nxfers, enum i3c_hdr_mode mode);
+
int i3c_device_do_setdasa(struct i3c_device *dev);
void i3c_device_get_info(const struct i3c_device *dev, struct i3c_device_info *info);
diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
index 12d532b012c5a..352bd41139569 100644
--- a/include/linux/i3c/master.h
+++ b/include/linux/i3c/master.h
@@ -472,6 +472,9 @@ struct i3c_master_controller_ops {
int (*priv_xfers)(struct i3c_dev_desc *dev,
struct i3c_priv_xfer *xfers,
int nxfers);
+ int (*priv_xfers_mode)(struct i3c_dev_desc *dev,
+ struct i3c_priv_xfer *xfers,
+ int nxfers, enum i3c_hdr_mode mode);
int (*attach_i2c_dev)(struct i2c_dev_desc *dev);
void (*detach_i2c_dev)(struct i2c_dev_desc *dev);
int (*i2c_xfers)(struct i2c_dev_desc *dev,