[PATCH 4/8] PCI: rockchip: Added poll and timeout to wait for PHY PLLs to be locked

From: Rick Wertenbroek <rick.wertenbroek@gmail.com>
To: alberto.dassatti@heig-vd.ch
Cc: xxm@rock-chips.com, wenrui.li@rock-chips.com,
	rick.wertenbroek@heig-vd.ch,
	"Rick Wertenbroek" <rick.wertenbroek@gmail.com>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
	"Heiko Stuebner" <heiko@sntech.de>,
	"Shawn Lin" <shawn.lin@rock-chips.com>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Jani Nikula" <jani.nikula@intel.com>,
	"Rodrigo Vivi" <rodrigo.vivi@intel.com>,
	"Mikko Kovanen" <mikko.kovanen@aavamobile.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-pci@vger.kernel.org
Subject: [PATCH 4/8] PCI: rockchip: Added poll and timeout to wait for PHY PLLs to be locked
Date: Thu, 26 Jan 2023 14:50:44 +0100	[thread overview]
Message-ID: <20230126135049.708524-5-rick.wertenbroek@gmail.com> (raw)
In-Reply-To: <20230126135049.708524-1-rick.wertenbroek@gmail.com>

The Rockchip PCIe controller did not wait until the PHY PLLs were locked.
This could cause hangs. Now the PHY PLLs status is checked through a side
channel bit with a poll and timeout. If the PHY PLLs cannot lock an error
is generated. This is documented in the TRM section 17.5.8.1 PCIe
Initalization Sequence.

Signed-off-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
---
 drivers/pci/controller/pcie-rockchip.c | 16 ++++++++++++++++
 drivers/pci/controller/pcie-rockchip.h |  2 ++
 2 files changed, 18 insertions(+)

diff --git a/drivers/pci/controller/pcie-rockchip.c b/drivers/pci/controller/pcie-rockchip.c
index 990a00e08..5f2e2dd5d 100644
--- a/drivers/pci/controller/pcie-rockchip.c
+++ b/drivers/pci/controller/pcie-rockchip.c
@@ -14,6 +14,7 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/gpio/consumer.h>
+#include <linux/iopoll.h>
 #include <linux/of_pci.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
@@ -153,6 +154,12 @@ int rockchip_pcie_parse_dt(struct rockchip_pcie *rockchip)
 }
 EXPORT_SYMBOL_GPL(rockchip_pcie_parse_dt);
 
+#define rockchip_pcie_read_addr(addr) rockchip_pcie_read(rockchip, addr)
+/* 100 ms max wait time for PHY PLLs to lock */
+#define RK_PHY_PLL_LOCK_TIMEOUT_US 100000
+/* Sleep should be less than 20ms */
+#define RK_PHY_PLL_LOCK_SLEEP_US 1000
+
 int rockchip_pcie_init_port(struct rockchip_pcie *rockchip)
 {
 	struct device *dev = rockchip->dev;
@@ -254,6 +261,15 @@ int rockchip_pcie_init_port(struct rockchip_pcie *rockchip)
 		}
 	}
 
+	err = readx_poll_timeout(rockchip_pcie_read_addr, PCIE_CLIENT_SIDE_BAND_STATUS,
+		regs, !(regs & PCIE_CLIENT_PHY_ST), RK_PHY_PLL_LOCK_SLEEP_US,
+		RK_PHY_PLL_LOCK_TIMEOUT_US);
+
+	if (err) {
+		dev_err(dev, "PHY PLLs could not lock, %d\n", err);
+		goto err_power_off_phy;
+	}
+
 	/*
 	 * Please don't reorder the deassert sequence of the following
 	 * four reset pins.
diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h
index 51a123e5c..f3a5ff1cf 100644
--- a/drivers/pci/controller/pcie-rockchip.h
+++ b/drivers/pci/controller/pcie-rockchip.h
@@ -38,6 +38,8 @@
 #define   PCIE_CLIENT_MODE_EP            HIWORD_UPDATE(0x0040, 0)
 #define   PCIE_CLIENT_GEN_SEL_1		  HIWORD_UPDATE(0x0080, 0)
 #define   PCIE_CLIENT_GEN_SEL_2		  HIWORD_UPDATE_BIT(0x0080)
+#define PCIE_CLIENT_SIDE_BAND_STATUS	(PCIE_CLIENT_BASE + 0x20)
+#define   PCIE_CLIENT_PHY_ST			BIT(12)
 #define PCIE_CLIENT_DEBUG_OUT_0		(PCIE_CLIENT_BASE + 0x3c)
 #define   PCIE_CLIENT_DEBUG_LTSSM_MASK		GENMASK(5, 0)
 #define   PCIE_CLIENT_DEBUG_LTSSM_L1		0x18
-- 
2.25.1

