phy: rockchip-snps-pcie3: fix bifurcation on rk3588

[ Upstream commit f8020dfb ]

So far all RK3588 boards use fully aggregated PCIe. CM3588 is one
of the few boards using this feature and apparently it is broken.

The PHY offers the following mapping options:

  port 0 lane 0 - always mapped to controller 0 (4L)
  port 0 lane 1 - to controller 0 or 2 (1L0)
  port 1 lane 0 - to controller 0 or 1 (2L)
  port 1 lane 1 - to controller 0, 1 or 3 (1L1)

The data-lanes DT property maps these as follows:

  0 = no controller (unsupported by the HW)
  1 = 4L
  2 = 2L
  3 = 1L0
  4 = 1L1

That allows the following configurations with first column being the
mainline data-lane mapping, second column being the downstream name,
third column being PCIE3PHY_GRF_CMN_CON0 and PHP_GRF_PCIESEL register
values and final column being the user visible lane setup:

  <1 1 1 1> = AGGREG = [4 0] = x4 (aggregation)
  <1 1 2 2> = NANBNB = [0 0] = x2 x2 (no bif.)
  <1 3 2 2> = NANBBI = [1 1] = x2 x1x1 (bif. of port 0)
  <1 1 2 4> = NABINB = [2 2] = x1x1 x2 (bif. of port 1)
  <1 3 2 4> = NABIBI = [3 3] = x1x1 x1x1 (bif. of both ports)

The driver currently does not program PHP_GRF_PCIESEL correctly, which
is fixed by this patch. As a side-effect the new logic is much simpler
than the old logic.

Fixes: 2e9bffc4 ("phy: rockchip: Support PCIe v3")
Signed-off-by: Michal Tomek <mtdev79b@gmail.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20240404-rk3588-pcie-bifurcation-fixes-v1-1-9907136eeafd@kernel.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>