linux-kernel - [PATCH 1/3] phy: rockchip-snps-pcie3: fix bifurcation on rk3588

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Date: Thu, 04 Apr 2024 19:11:26 +0200
From: Sebastian Reichel <sre@...nel.org>
To: Vinod Koul <vkoul@...nel.org>, 
 Kishon Vijay Abraham I <kishon@...nel.org>, 
 Heiko Stuebner <heiko@...ech.de>
Cc: Shawn Lin <shawn.lin@...k-chips.com>, Michal Tomek <mtdev79b@...il.com>, 
 linux-phy@...ts.infradead.org, linux-rockchip@...ts.infradead.org, 
 linux-kernel@...r.kernel.org, 
 Sebastian Reichel <sebastian.reichel@...labora.com>
Subject: [PATCH 1/3] phy: rockchip-snps-pcie3: fix bifurcation on rk3588

From: Michal Tomek <mtdev79b@...il.com>

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: 2e9bffc4f713 ("phy: rockchip: Support PCIe v3")
Signed-off-by: Michal Tomek <mtdev79b@...il.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>
---
 drivers/phy/rockchip/phy-rockchip-snps-pcie3.c | 24 ++++++++----------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/drivers/phy/rockchip/phy-rockchip-snps-pcie3.c b/drivers/phy/rockchip/phy-rockchip-snps-pcie3.c
index 121e5961ce11..d5bcc9c42b28 100644
--- a/drivers/phy/rockchip/phy-rockchip-snps-pcie3.c
+++ b/drivers/phy/rockchip/phy-rockchip-snps-pcie3.c
@@ -132,7 +132,7 @@ static const struct rockchip_p3phy_ops rk3568_ops = {
 static int rockchip_p3phy_rk3588_init(struct rockchip_p3phy_priv *priv)
 {
 	u32 reg = 0;
-	u8 mode = 0;
+	u8 mode = RK3588_LANE_AGGREGATION; /* default */
 	int ret;
 
 	/* Deassert PCIe PMA output clamp mode */
@@ -140,28 +140,20 @@ static int rockchip_p3phy_rk3588_init(struct rockchip_p3phy_priv *priv)
 
 	/* Set bifurcation if needed */
 	for (int i = 0; i < priv->num_lanes; i++) {
-		if (!priv->lanes[i])
-			mode |= (BIT(i) << 3);
-
 		if (priv->lanes[i] > 1)
-			mode |= (BIT(i) >> 1);
-	}
-
-	if (!mode)
-		reg = RK3588_LANE_AGGREGATION;
-	else {
-		if (mode & (BIT(0) | BIT(1)))
-			reg |= RK3588_BIFURCATION_LANE_0_1;
-
-		if (mode & (BIT(2) | BIT(3)))
-			reg |= RK3588_BIFURCATION_LANE_2_3;
+			mode &= ~RK3588_LANE_AGGREGATION;
+		if (priv->lanes[i] == 3)
+			mode |= RK3588_BIFURCATION_LANE_0_1;
+		if (priv->lanes[i] == 4)
+			mode |= RK3588_BIFURCATION_LANE_2_3;
 	}
 
+	reg = mode;
 	regmap_write(priv->phy_grf, RK3588_PCIE3PHY_GRF_CMN_CON0, (0x7<<16) | reg);
 
 	/* Set pcie1ln_sel in PHP_GRF_PCIESEL_CON */
 	if (!IS_ERR(priv->pipe_grf)) {
-		reg = (mode & (BIT(6) | BIT(7))) >> 6;
+		reg = mode & 3;
 		if (reg)
 			regmap_write(priv->pipe_grf, PHP_GRF_PCIESEL_CON,
 				     (reg << 16) | reg);

-- 
2.43.0