Re: [RFC PATCH v5 3/4] phy: rockchip-pcie: Enable all four lanes

[Robin Murphy]

On 2025-06-20 1:26 pm, Geraldo Nascimento wrote:
> On Fri, Jun 20, 2025 at 01:04:46PM +0100, Robin Murphy wrote:
> > On 2025-06-13 6:03 pm, Geraldo Nascimento wrote:
> > > Current code enables only Lane 0 because pwr_cnt will be incremented
> > > on first call to the function. Use for-loop to enable all 4 lanes
> > > through GRF.
> >
> > If this was really necessary, then surely it would also need the
> > equivalent changes in rockchip_pcie_phy_power_off() too?
> >
> > However, I'm not sure it *is* necessary - the NVMe on my RK3399 board
> > happily claims to be using an x4 link, so I stuck a print of inst->index
> > in this function, and sure enough I do see it being called for each
> > instance already:
> >
> > [    1.737479] phy phy-ff770000.syscon:pcie-phy.1: power_on 0
> > [    1.738810] phy phy-ff770000.syscon:pcie-phy.2: power_on 1
> > [    1.745193] phy phy-ff770000.syscon:pcie-phy.3: power_on 2
> > [    1.745196] phy phy-ff770000.syscon:pcie-phy.4: power_on 3
>
> Hi Robin, and thanks for caring, it's excellent to rely on your
> extensive expertise on ARM in general and RK3399 specifically!
>
> However, on my board I'm positive it does not work without proposed
> patch and I get stuck with x1 link without it.
>
> There are currently very similar patches applied downstream to Armbian
> and OpenWRT so at least I'm confident that is not only my board which is
> quirky and other people experienced the same problem.

Ah, I put that print at the top of the function - on second look now I
see that there's an awkward mix of per-lane and global data, and pwr_cnt
is actually the latter. Sure enough, moving the print past that check I
only see it once.

However, I still don't think blindly enabling all the lanes is the right
thing to do either; I'd imagine something like the (untested) diff below
would be more appropriate. That would then seem to balance with what
power_off is doing.

Thanks,
Robin.

----->8-----
diff --git a/drivers/phy/rockchip/phy-rockchip-pcie.c b/drivers/phy/rockchip/phy-rockchip-pcie.c
index bd44af36c67a..a34a983db16c 100644
--- a/drivers/phy/rockchip/phy-rockchip-pcie.c
+++ b/drivers/phy/rockchip/phy-rockchip-pcie.c
@@ -160,11 +160,8 @@ static int rockchip_pcie_phy_power_on(struct phy *phy)
 
 	guard(mutex)(&rk_phy->pcie_mutex);
 
-	if (rk_phy->pwr_cnt++) {
-		return 0;
-	}
-
-	err = reset_control_deassert(rk_phy->phy_rst);
+	if (rk_phy->pwr_cnt++)
+		err = reset_control_deassert(rk_phy->phy_rst);
 	if (err) {
 		dev_err(&phy->dev, "deassert phy_rst err %d\n", err);
 		rk_phy->pwr_cnt--;
@@ -181,6 +178,8 @@ static int rockchip_pcie_phy_power_on(struct phy *phy)
 		     HIWORD_UPDATE(!PHY_LANE_IDLE_OFF,
 				   PHY_LANE_IDLE_MASK,
 				   PHY_LANE_IDLE_A_SHIFT + inst->index));
+	if (rk_phy->pwr_cnt)
+		return 0;
 
 	/*
 	 * No documented timeout value for phy operation below,