i3c: master: Fix dynamic address leak when 'assigned-address' is present

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>
Link: https://lore.kernel.org/r/20241021-i3c_dts_assign-v8-3-4098b8bde01e@nxp.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 1bf9cb138f77fac6d22477c42b58007dd8fcb54d..5a089be7e0728e8ab60a68db86efcd1b13b6e45f 100644 (file)
--- 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.