[PATCH v8 0/3] I3C: master: fix the address assign issue if assign-address is exist in dts

[PATCH v8 0/3] I3C: master: fix the address assign issue if assign-address is exist in dts

[Frank Li]

These patches are split from
https://lore.kernel.org/linux-i3c/ZvrAuOBLgi+HtrPD@lizhi-Precision-Tower-5810/#R

There are discussion on
https://lore.kernel.org/linux-i3c/20240819-i3c_fix-v3-0-7d69f7b0a05e@nxp.com/T/#m16fa9bb875b0ae9d37c5f6e91f90e375551c6366

Basic back ground is
The current framework is
1. get free i3c dynamic address
2. if found dt have assign-address for such device (identify by PID),
change to such address.

There are problem in current implement.
If device A have assign-address 0xa, device B have assign-address 0xB,
which described at dts file.

If device A is not ready during i3c probe, and device B hotjoin happen,
0xA will assign to device B, so if device A hotjoin later, address 0xA
Can't assign to A because B already use it.

Mirquel's opinion is return address B when B hotjoin by scan dts by PID.

The issue is the controller HCI (i3C standard),

I3C HCI Spec 1.2, sec 6.4.1, when do DAA,  "DAA CMD and dynmatic address"
queue to cmd together.  We don't know PID before DAA CMD. So dynamic
address can NOT get based on PID.

When do DAA in HCI, it needs a dynamtic address firstly before get PID
information.

Consider this need more time to discuss, so split from previous big serial
to avoid prevent other fix patches can't be merged into i3c tree.

This patches's overall design:

1. keep current frame's work flow
2. reserver all address, which assigned in dts.
3. the device with assigned address have high priorioty to get such
address.
4. if all address without assigned by dt are used, use offline devices's
assigned address.

To: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: linux-i3c@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: arnd@arndb.de
Cc: bbrezillon@kernel.org
Cc: boris.brezillon@collabora.com
Cc: conor.culhane@silvaco.com
Cc: gregkh@linuxfoundation.org
Cc: imx@lists.linux.dev
Cc: linux-i3c@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: miquel.raynal@bootlin.com
Cc: pthombar@cadence.com
Cc: ravindra.yashvant.shinde@nxp.com

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Changes in v8:
- see each patch.
- Link to v7: https://lore.kernel.org/r/20241008-i3c_dts_assign-v7-0-96ec93d1f34c@nxp.com

Changes in v7:
- see each patch
- Link to v6: https://lore.kernel.org/r/20241003-i3c_dts_assign-v6-0-eae2569c92ca@nxp.com

Changes in v2:
- see each patch
- Link to v1: https://lore.kernel.org/r/20241001-i3c_dts_assign-v1-0-6ba83dc15eb8@nxp.com

---
Frank Li (3):
      i3c: master: Replace hard code 2 with macro I3C_ADDR_SLOT_STATUS_BITS
      i3c: master: Extend address status bit to 4 and add I3C_ADDR_SLOT_EXT_DESIRED
      i3c: master: Fix dynamic address leak when 'assigned-address' is present

 drivers/i3c/master.c       | 82 +++++++++++++++++++++++++++++++++-------------
 include/linux/i3c/master.h |  9 +++--
 2 files changed, 67 insertions(+), 24 deletions(-)
---
base-commit: 77df9e4bb2224d8ffbddec04c333a9d7965dad6c
change-id: 20241001-i3c_dts_assign-d615fc33cc1d

Best regards,
---
Frank Li <Frank.Li@nxp.com>


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[PATCH v8 1/3] i3c: master: Replace hard code 2 with macro I3C_ADDR_SLOT_STATUS_BITS

[Frank Li]

Replace the hardcoded value 2, which indicates 2 bits for I3C address
status, with the predefined macro I3C_ADDR_SLOT_STATUS_BITS.

Improve maintainability and extensibility of the code.

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Change from v6 to v8
- none

Change from v5 to v6
- fix version, should start from v5
- add Miquel's review tag

Change from v3 to v4
- rename to I3C_ADDR_SLOT_STATUS_BITS
---
 drivers/i3c/master.c       | 4 ++--
 include/linux/i3c/master.h | 4 +++-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 6f3eb710a75d6..dcf8d23c5941a 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -348,7 +348,7 @@ static enum i3c_addr_slot_status
 i3c_bus_get_addr_slot_status(struct i3c_bus *bus, u16 addr)
 {
 	unsigned long status;
-	int bitpos = addr * 2;
+	int bitpos = addr * I3C_ADDR_SLOT_STATUS_BITS;
 
 	if (addr > I2C_MAX_ADDR)
 		return I3C_ADDR_SLOT_RSVD;
@@ -362,7 +362,7 @@ i3c_bus_get_addr_slot_status(struct i3c_bus *bus, u16 addr)
 static void i3c_bus_set_addr_slot_status(struct i3c_bus *bus, u16 addr,
 					 enum i3c_addr_slot_status status)
 {
-	int bitpos = addr * 2;
+	int bitpos = addr * I3C_ADDR_SLOT_STATUS_BITS;
 	unsigned long *ptr;
 
 	if (addr > I2C_MAX_ADDR)
diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
index 2a1ed05d5782a..2100547b2d8d2 100644
--- a/include/linux/i3c/master.h
+++ b/include/linux/i3c/master.h
@@ -313,6 +313,8 @@ enum i3c_addr_slot_status {
 	I3C_ADDR_SLOT_STATUS_MASK = 3,
 };
 
+#define I3C_ADDR_SLOT_STATUS_BITS 2
+
 /**
  * struct i3c_bus - I3C bus object
  * @cur_master: I3C master currently driving the bus. Since I3C is multi-master
@@ -354,7 +356,7 @@ enum i3c_addr_slot_status {
 struct i3c_bus {
 	struct i3c_dev_desc *cur_master;
 	int id;
-	unsigned long addrslots[((I2C_MAX_ADDR + 1) * 2) / BITS_PER_LONG];
+	unsigned long addrslots[((I2C_MAX_ADDR + 1) * I3C_ADDR_SLOT_STATUS_BITS) / BITS_PER_LONG];
 	enum i3c_bus_mode mode;
 	struct {
 		unsigned long i3c;

-- 
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[PATCH v8 2/3] i3c: master: Extend address status bit to 4 and add I3C_ADDR_SLOT_EXT_DESIRED

[Frank Li]

Extend the address status bit to 4 and introduce the
I3C_ADDR_SLOT_EXT_DESIRED macro to indicate that a device prefers a
specific address. This is generally set by the 'assigned-address' in the
device tree source (dts) file.

 ┌────┬─────────────┬───┬─────────┬───┐
 │S/Sr│ 7'h7E RnW=0 │ACK│ ENTDAA  │ T ├────┐
 └────┴─────────────┴───┴─────────┴───┘    │
 ┌─────────────────────────────────────────┘
 │  ┌──┬─────────────┬───┬─────────────────┬────────────────┬───┬─────────┐
 └─►│Sr│7'h7E RnW=1  │ACK│48bit UID BCR DCR│Assign 7bit Addr│PAR│ ACK/NACK│
    └──┴─────────────┴───┴─────────────────┴────────────────┴───┴─────────┘

Some master controllers (such as HCI) need to prepare the entire above
transaction before sending it out to the I3C bus. This means that a 7-bit
dynamic address needs to be allocated before knowing the target device's
UID information.

However, some I3C targets may request specific addresses (called as
"init_dyn_addr"), which is typically specified by the DT-'s
assigned-address property. Lower addresses having higher IBI priority. If
it is available, i3c_bus_get_free_addr() preferably return a free address
that is not in the list of desired addresses (called as "init_dyn_addr").
This allows the device with the "init_dyn_addr" to switch to its
"init_dyn_addr" when it hot-joins the I3C bus. Otherwise, if the
"init_dyn_addr" is already in use by another I3C device, the target device
will not be able to switch to its desired address.

If the previous step fails, fallback returning one of the remaining
unassigned address, regardless of its state in the desired list.

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Change from v7 to v8
- Add Miquel's review tag
- align to (, fixed a checkpatch.pl --strict warning

Change from v6 to v7
- always use i3c_bus_get_addr_slot_status_mask() in i3c_bus_get_free_addr
- ((unsigned long)status & mask) in i3c_bus_set_addr_slot_status_mask()
incase status bigger than mask;

Change from v5 to v6
- fix version number, should start v5
- change to I3C_ADDR_SLOT_EXT_DESIRED
- remove _ext function and direct use _mask function
- rework commit message and comments according to Miquèl's feedback.
- change mask type to u32
change from v3 to v4
- rewrite commit message and comment for i3c_bus_get_free_addr()
---
 drivers/i3c/master.c       | 65 ++++++++++++++++++++++++++++++++++++++--------
 include/linux/i3c/master.h |  7 +++--
 2 files changed, 59 insertions(+), 13 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index dcf8d23c5941a..1bf9cb138f77f 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -345,7 +345,7 @@ const struct bus_type i3c_bus_type = {
 EXPORT_SYMBOL_GPL(i3c_bus_type);
 
 static enum i3c_addr_slot_status
-i3c_bus_get_addr_slot_status(struct i3c_bus *bus, u16 addr)
+i3c_bus_get_addr_slot_status_mask(struct i3c_bus *bus, u16 addr, u32 mask)
 {
 	unsigned long status;
 	int bitpos = addr * I3C_ADDR_SLOT_STATUS_BITS;
@@ -356,11 +356,17 @@ i3c_bus_get_addr_slot_status(struct i3c_bus *bus, u16 addr)
 	status = bus->addrslots[bitpos / BITS_PER_LONG];
 	status >>= bitpos % BITS_PER_LONG;
 
-	return status & I3C_ADDR_SLOT_STATUS_MASK;
+	return status & mask;
 }
 
-static void i3c_bus_set_addr_slot_status(struct i3c_bus *bus, u16 addr,
-					 enum i3c_addr_slot_status status)
+static enum i3c_addr_slot_status
+i3c_bus_get_addr_slot_status(struct i3c_bus *bus, u16 addr)
+{
+	return i3c_bus_get_addr_slot_status_mask(bus, addr, I3C_ADDR_SLOT_STATUS_MASK);
+}
+
+static void i3c_bus_set_addr_slot_status_mask(struct i3c_bus *bus, u16 addr,
+					      enum i3c_addr_slot_status status, u32 mask)
 {
 	int bitpos = addr * I3C_ADDR_SLOT_STATUS_BITS;
 	unsigned long *ptr;
@@ -369,9 +375,14 @@ static void i3c_bus_set_addr_slot_status(struct i3c_bus *bus, u16 addr,
 		return;
 
 	ptr = bus->addrslots + (bitpos / BITS_PER_LONG);
-	*ptr &= ~((unsigned long)I3C_ADDR_SLOT_STATUS_MASK <<
-						(bitpos % BITS_PER_LONG));
-	*ptr |= (unsigned long)status << (bitpos % BITS_PER_LONG);
+	*ptr &= ~((unsigned long)mask << (bitpos % BITS_PER_LONG));
+	*ptr |= ((unsigned long)status & mask) << (bitpos % BITS_PER_LONG);
+}
+
+static void i3c_bus_set_addr_slot_status(struct i3c_bus *bus, u16 addr,
+					 enum i3c_addr_slot_status status)
+{
+	i3c_bus_set_addr_slot_status_mask(bus, addr, status, I3C_ADDR_SLOT_STATUS_MASK);
 }
 
 static bool i3c_bus_dev_addr_is_avail(struct i3c_bus *bus, u8 addr)
@@ -383,13 +394,44 @@ static bool i3c_bus_dev_addr_is_avail(struct i3c_bus *bus, u8 addr)
 	return status == I3C_ADDR_SLOT_FREE;
 }
 
+/*
+ * ┌────┬─────────────┬───┬─────────┬───┐
+ * │S/Sr│ 7'h7E RnW=0 │ACK│ ENTDAA  │ T ├────┐
+ * └────┴─────────────┴───┴─────────┴───┘    │
+ * ┌─────────────────────────────────────────┘
+ * │  ┌──┬─────────────┬───┬─────────────────┬────────────────┬───┬─────────┐
+ * └─►│Sr│7'h7E RnW=1  │ACK│48bit UID BCR DCR│Assign 7bit Addr│PAR│ ACK/NACK│
+ *    └──┴─────────────┴───┴─────────────────┴────────────────┴───┴─────────┘
+ * Some master controllers (such as HCI) need to prepare the entire above transaction before
+ * sending it out to the I3C bus. This means that a 7-bit dynamic address needs to be allocated
+ * before knowing the target device's UID information.
+ *
+ * However, some I3C targets may request specific addresses (called as "init_dyn_addr"), which is
+ * typically specified by the DT-'s assigned-address property. Lower addresses having higher IBI
+ * priority. If it is available, i3c_bus_get_free_addr() preferably return a free address that is
+ * not in the list of desired addresses (called as "init_dyn_addr"). This allows the device with
+ * the "init_dyn_addr" to switch to its "init_dyn_addr" when it hot-joins the I3C bus. Otherwise,
+ * if the "init_dyn_addr" is already in use by another I3C device, the target device will not be
+ * able to switch to its desired address.
+ *
+ * If the previous step fails, fallback returning one of the remaining unassigned address,
+ * regardless of its state in the desired list.
+ */
 static int i3c_bus_get_free_addr(struct i3c_bus *bus, u8 start_addr)
 {
 	enum i3c_addr_slot_status status;
 	u8 addr;
 
 	for (addr = start_addr; addr < I3C_MAX_ADDR; addr++) {
-		status = i3c_bus_get_addr_slot_status(bus, addr);
+		status = i3c_bus_get_addr_slot_status_mask(bus, addr,
+							   I3C_ADDR_SLOT_EXT_STATUS_MASK);
+		if (status == I3C_ADDR_SLOT_FREE)
+			return addr;
+	}
+
+	for (addr = start_addr; addr < I3C_MAX_ADDR; addr++) {
+		status = i3c_bus_get_addr_slot_status_mask(bus, addr,
+							   I3C_ADDR_SLOT_STATUS_MASK);
 		if (status == I3C_ADDR_SLOT_FREE)
 			return addr;
 	}
@@ -1918,9 +1960,10 @@ static int i3c_master_bus_init(struct i3c_master_controller *master)
 			goto err_rstdaa;
 		}
 
-		i3c_bus_set_addr_slot_status(&master->bus,
-					     i3cboardinfo->init_dyn_addr,
-					     I3C_ADDR_SLOT_I3C_DEV);
+		i3c_bus_set_addr_slot_status_mask(&master->bus,
+						  i3cboardinfo->init_dyn_addr,
+						  I3C_ADDR_SLOT_I3C_DEV | I3C_ADDR_SLOT_EXT_DESIRED,
+						  I3C_ADDR_SLOT_EXT_STATUS_MASK);
 
 		/*
 		 * Only try to create/attach devices that have a static
diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
index 2100547b2d8d2..6e5328c6c6afd 100644
--- a/include/linux/i3c/master.h
+++ b/include/linux/i3c/master.h
@@ -298,7 +298,8 @@ enum i3c_open_drain_speed {
  * @I3C_ADDR_SLOT_I2C_DEV: address is assigned to an I2C device
  * @I3C_ADDR_SLOT_I3C_DEV: address is assigned to an I3C device
  * @I3C_ADDR_SLOT_STATUS_MASK: address slot mask
- *
+ * @I3C_ADDR_SLOT_EXT_DESIRED: the bitmask represents addresses that are preferred by some devices,
+ *			       such as the "assigned-address" property in a device tree source.
  * On an I3C bus, addresses are assigned dynamically, and we need to know which
  * addresses are free to use and which ones are already assigned.
  *
@@ -311,9 +312,11 @@ enum i3c_addr_slot_status {
 	I3C_ADDR_SLOT_I2C_DEV,
 	I3C_ADDR_SLOT_I3C_DEV,
 	I3C_ADDR_SLOT_STATUS_MASK = 3,
+	I3C_ADDR_SLOT_EXT_STATUS_MASK = 7,
+	I3C_ADDR_SLOT_EXT_DESIRED = BIT(2),
 };
 
-#define I3C_ADDR_SLOT_STATUS_BITS 2
+#define I3C_ADDR_SLOT_STATUS_BITS 4
 
 /**
  * struct i3c_bus - I3C bus object

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[PATCH v8 3/3] i3c: master: Fix dynamic address leak when 'assigned-address' is present

[Frank Li]

If the DTS contains 'assigned-address', a dynamic address leak occurs
during hotjoin events.

Assume a device have assigned-address 0xb.
  - Device issue Hotjoin
  - Call i3c_master_do_daa()
  - Call driver xxx_do_daa()
  - Call i3c_master_get_free_addr() to get dynamic address 0x9
  - i3c_master_add_i3c_dev_locked(0x9)
  -     expected_dyn_addr  = newdev->boardinfo->init_dyn_addr (0xb);
  -     i3c_master_reattach_i3c_dev(newdev(0xb), old_dyn_addr(0x9));
  -         if (dev->info.dyn_addr != old_dyn_addr &&
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 0xb != 0x9 -> TRUE
                (!dev->boardinfo ||
                 ^^^^^^^^^^^^^^^ ->  FALSE
                 dev->info.dyn_addr != dev->boardinfo->init_dyn_addr)) {
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                 0xb != 0xb      ->  FALSE
                 ...
                 i3c_bus_set_addr_slot_status(&master->bus, old_dyn_addr,
                                                     I3C_ADDR_SLOT_FREE);
		 ^^^
                 This will be skipped. So old_dyn_addr never free
            }

  - i3c_master_get_free_addr() will return increased sequence number.

Remove dev->info.dyn_addr != dev->boardinfo->init_dyn_addr condition check.
dev->info.dyn_addr should be checked before calling this function because
i3c_master_setnewda_locked() has already been called and the target device
has already accepted dyn_addr. It is too late to check if dyn_addr is free
in i3c_master_reattach_i3c_dev().

Add check to ensure expected_dyn_addr is free before
i3c_master_setnewda_locked().

Fixes: cc3a392d69b6 ("i3c: master: fix for SETDASA and DAA process")
Cc: stable@kernel.org
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Change from v7 to v8
- Add miquel review tag

Chagne v6 to v7
- none

Chagne v5 to v6
- fixed version number to v5
- fix merge conflict because change function name and macro name.

Change v3 to v4
- none
---
 drivers/i3c/master.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 1bf9cb138f77f..5a089be7e0728 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -1548,16 +1548,9 @@ static int i3c_master_reattach_i3c_dev(struct i3c_dev_desc *dev,
 				       u8 old_dyn_addr)
 {
 	struct i3c_master_controller *master = i3c_dev_get_master(dev);
-	enum i3c_addr_slot_status status;
 	int ret;
 
-	if (dev->info.dyn_addr != old_dyn_addr &&
-	    (!dev->boardinfo ||
-	     dev->info.dyn_addr != dev->boardinfo->init_dyn_addr)) {
-		status = i3c_bus_get_addr_slot_status(&master->bus,
-						      dev->info.dyn_addr);
-		if (status != I3C_ADDR_SLOT_FREE)
-			return -EBUSY;
+	if (dev->info.dyn_addr != old_dyn_addr) {
 		i3c_bus_set_addr_slot_status(&master->bus,
 					     dev->info.dyn_addr,
 					     I3C_ADDR_SLOT_I3C_DEV);
@@ -1960,9 +1953,10 @@ static int i3c_master_bus_init(struct i3c_master_controller *master)
 			goto err_rstdaa;
 		}
 
+		/* Do not mark as occupied until real device exist in bus */
 		i3c_bus_set_addr_slot_status_mask(&master->bus,
 						  i3cboardinfo->init_dyn_addr,
-						  I3C_ADDR_SLOT_I3C_DEV | I3C_ADDR_SLOT_EXT_DESIRED,
+						  I3C_ADDR_SLOT_EXT_DESIRED,
 						  I3C_ADDR_SLOT_EXT_STATUS_MASK);
 
 		/*
@@ -2126,7 +2120,8 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
 	else
 		expected_dyn_addr = newdev->info.dyn_addr;
 
-	if (newdev->info.dyn_addr != expected_dyn_addr) {
+	if (newdev->info.dyn_addr != expected_dyn_addr &&
+	    i3c_bus_get_addr_slot_status(&master->bus, expected_dyn_addr) == I3C_ADDR_SLOT_FREE) {
 		/*
 		 * Try to apply the expected dynamic address. If it fails, keep
 		 * the address assigned by the master.

-- 
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Re: [PATCH v8 0/3] I3C: master: fix the address assign issue if assign-address is exist in dts

[Alexandre Belloni]

On Mon, 21 Oct 2024 11:45:05 -0400, Frank Li wrote:
> These patches are split from
> https://lore.kernel.org/linux-i3c/ZvrAuOBLgi+HtrPD@lizhi-Precision-Tower-5810/#R
> 
> There are discussion on
> https://lore.kernel.org/linux-i3c/20240819-i3c_fix-v3-0-7d69f7b0a05e@nxp.com/T/#m16fa9bb875b0ae9d37c5f6e91f90e375551c6366
> 
> Basic back ground is
> The current framework is
> 1. get free i3c dynamic address
> 2. if found dt have assign-address for such device (identify by PID),
> change to such address.
> 
> [...]

Applied, thanks!

[1/3] i3c: master: Replace hard code 2 with macro I3C_ADDR_SLOT_STATUS_BITS
      https://git.kernel.org/abelloni/c/16aed0a6520b
[2/3] i3c: master: Extend address status bit to 4 and add I3C_ADDR_SLOT_EXT_DESIRED
      https://git.kernel.org/abelloni/c/2f552fa28059
[3/3] i3c: master: Fix dynamic address leak when 'assigned-address' is present
      https://git.kernel.org/abelloni/c/851bd21cdb55

Best regards,

-- 
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Embedded Linux and Kernel engineering
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