Mika writes:

thunderbolt: Changes for v6.4 merge window

This includes following Thunderbolt/USB4 changes for the v6.4 merge
window:

  - Refactoring of DROM read code paths
  - Convert to use SI units from units.h
  - A couple of cleanups

All these have been in linux-next with no reported issues.

* tag 'thunderbolt-for-v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt:
  thunderbolt: Introduce usb4_port_sb_opcode_err_to_errno() helper
  thunderbolt: Make use of SI units from units.h
  thunderbolt: Get rid of redundant 'else'
  thunderbolt: Refactor DROM reading
  thunderbolt: use `tb_eeprom_get_drom_offset` to discover DROM offset

The usb4_port_sb_opcode_err_to_errno() converts from USB4 error codes
to the Linux errno space. In particular, this makes the intention
of the repeating usb4_port_retimer_read() call in the
usb4_port_retimer_nvm_authenticate_status() clearer.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

In a couple of places it seems reasonable to use MEGA intead
of explicit number. It makes code more readable and robust.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

In the snippets like the following

	if (...)
		return / goto / break / continue ...;
	else
		...

the 'else' is redundant. Get rid of it.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

cppcheck reports
drivers/thunderbolt/nhi.c:74:7: style: Local variable 'bit' shadows outer variable [shadowVariable]
  int bit;
      ^
drivers/thunderbolt/nhi.c:66:6: note: Shadowed declaration
 int bit = ring_interrupt_index(ring) & 31;
     ^
drivers/thunderbolt/nhi.c:74:7: note: Shadow variable
  int bit;
      ^
For readablity rename the outer to interrupt_bit and the innner
to auto_clear_bit.

Fixes: 468c49f44759 ("thunderbolt: Disable interrupt auto clear for ring")
Cc: stable@vger.kernel.org
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

When interrupt auto clear is programmed, any read to the interrupt
status register will clear all interrupts.  If two interrupts have
come in before one can be serviced then this will cause lost interrupts.

On AMD USB4 routers this has manifested in odd problems particularly
with long strings of control tranfers such as reading the DROM via bit
banging.

Instead of clearing interrupts automatically, clear the bit corresponding
to the given ring's interrupt in the ISR.

Fixes: 7a1808f82a37 ("thunderbolt: Handle ring interrupt by reading interrupt status register")
Cc: Sanju Mehta <Sanju.Mehta@amd.com>
Cc: stable@vger.kernel.org
Tested-by: Anson Tsao <anson.tsao@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

`ring_interrupt_index` doesn't change the data for `ring` so mark it as
const. This is needed by the following patch that disables interrupt
auto clear for rings.

Cc: Sanju Mehta <Sanju.Mehta@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

The NVM reading code has a series of gotos that potentially introduce
unexpected behaviors with retries if something unexpected has failed
to parse.

Refactor the code to remove the gotos and drop the retry logic.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
[mw: renamed root switch to host router, split device handling too]
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

The static function `tb_eeprom_get_drom_offset` has more safety guards
for the DROM offset fetching.  Use this instead of just `tb_sw_read`

No intended functional changes.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

When tunneling aggregated USB3 (20 Gb/s) the bandwidth values that are
programmed to the ADP_USB3_CS_2 go higher than 4096 and that does not
fit anymore to the 12-bit field. Fix this by scaling the value using
the scale field accordingly.

Fixes: 3b1d8d577ca8 ("thunderbolt: Implement USB3 bandwidth negotiation routines")
Cc: stable@vger.kernel.org
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>