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authorBjorn Helgaas <bhelgaas@google.com>2020-06-04 20:59:14 +0300
committerBjorn Helgaas <bhelgaas@google.com>2020-06-04 20:59:14 +0300
commit075a383389d71b0afde7feacd1a6ad6f247fa411 (patch)
tree587fe23f0793ae8db1d630fff103b79a2b5ae0e1 /drivers/pci
parent39a1af76195086349c4302f01e498a5fcbcb11d6 (diff)
parente89897c9dec7f859a93b8364709851c3a7418ac3 (diff)
downloadlinux-075a383389d71b0afde7feacd1a6ad6f247fa411.tar.xz
Merge branch 'remotes/lorenzo/pci/aardvark'
- Train link immediately after enabling link training to avoid issues with Compex WLE900VX and Turris MOX devices (Pali Rohár) - Remove ASPM config and let the PCI core do it (Pali Rohár) - Interpret zero 'max-link-speed' value as invalid (Pali Rohár) - Respect the 'max-link-speed' property and improve link training (Marek Behún) - Issue PERST via GPIO (Pali Rohár) - Add PHY support (Marek Behún) - Use standard PCIe capability macros (Pali Rohár) - Document new 'max-link-speed', 'phys', and 'reset-gpios' properties (Marek Behún) * remotes/lorenzo/pci/aardvark: dt-bindings: PCI: aardvark: Describe new properties PCI: aardvark: Replace custom macros by standard linux/pci_regs.h macros PCI: aardvark: Add PHY support PCI: aardvark: Add FIXME comment for PCIE_CORE_CMD_STATUS_REG access PCI: aardvark: Issue PERST via GPIO PCI: aardvark: Improve link training PCI: of: Zero max-link-speed value is invalid PCI: aardvark: Don't blindly enable ASPM L0s and don't write to read-only register PCI: aardvark: Train link immediately after enabling training
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/controller/pci-aardvark.c263
-rw-r--r--drivers/pci/of.c2
2 files changed, 220 insertions, 45 deletions
diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 40a4257f0df1..90ff291c24f0 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -9,15 +9,18 @@
*/
#include <linux/delay.h>
+#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/init.h>
+#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/msi.h>
#include <linux/of_address.h>
+#include <linux/of_gpio.h>
#include <linux/of_pci.h>
#include "../pci.h"
@@ -31,16 +34,6 @@
#define PCIE_CORE_CMD_MEM_IO_REQ_EN BIT(2)
#define PCIE_CORE_DEV_REV_REG 0x8
#define PCIE_CORE_PCIEXP_CAP 0xc0
-#define PCIE_CORE_DEV_CTRL_STATS_REG 0xc8
-#define PCIE_CORE_DEV_CTRL_STATS_RELAX_ORDER_DISABLE (0 << 4)
-#define PCIE_CORE_DEV_CTRL_STATS_MAX_PAYLOAD_SZ_SHIFT 5
-#define PCIE_CORE_DEV_CTRL_STATS_SNOOP_DISABLE (0 << 11)
-#define PCIE_CORE_DEV_CTRL_STATS_MAX_RD_REQ_SIZE_SHIFT 12
-#define PCIE_CORE_DEV_CTRL_STATS_MAX_RD_REQ_SZ 0x2
-#define PCIE_CORE_LINK_CTRL_STAT_REG 0xd0
-#define PCIE_CORE_LINK_L0S_ENTRY BIT(0)
-#define PCIE_CORE_LINK_TRAINING BIT(5)
-#define PCIE_CORE_LINK_WIDTH_SHIFT 20
#define PCIE_CORE_ERR_CAPCTL_REG 0x118
#define PCIE_CORE_ERR_CAPCTL_ECRC_CHK_TX BIT(5)
#define PCIE_CORE_ERR_CAPCTL_ECRC_CHK_TX_EN BIT(6)
@@ -101,6 +94,8 @@
#define PCIE_CORE_CTRL2_STRICT_ORDER_ENABLE BIT(5)
#define PCIE_CORE_CTRL2_OB_WIN_ENABLE BIT(6)
#define PCIE_CORE_CTRL2_MSI_ENABLE BIT(10)
+#define PCIE_CORE_REF_CLK_REG (CONTROL_BASE_ADDR + 0x14)
+#define PCIE_CORE_REF_CLK_TX_ENABLE BIT(1)
#define PCIE_MSG_LOG_REG (CONTROL_BASE_ADDR + 0x30)
#define PCIE_ISR0_REG (CONTROL_BASE_ADDR + 0x40)
#define PCIE_MSG_PM_PME_MASK BIT(7)
@@ -201,7 +196,10 @@ struct advk_pcie {
struct mutex msi_used_lock;
u16 msi_msg;
int root_bus_nr;
+ int link_gen;
struct pci_bridge_emul bridge;
+ struct gpio_desc *reset_gpio;
+ struct phy *phy;
};
static inline void advk_writel(struct advk_pcie *pcie, u32 val, u64 reg)
@@ -214,6 +212,11 @@ static inline u32 advk_readl(struct advk_pcie *pcie, u64 reg)
return readl(pcie->base + reg);
}
+static inline u16 advk_read16(struct advk_pcie *pcie, u64 reg)
+{
+ return advk_readl(pcie, (reg & ~0x3)) >> ((reg & 0x3) * 8);
+}
+
static int advk_pcie_link_up(struct advk_pcie *pcie)
{
u32 val, ltssm_state;
@@ -225,20 +228,16 @@ static int advk_pcie_link_up(struct advk_pcie *pcie)
static int advk_pcie_wait_for_link(struct advk_pcie *pcie)
{
- struct device *dev = &pcie->pdev->dev;
int retries;
/* check if the link is up or not */
for (retries = 0; retries < LINK_WAIT_MAX_RETRIES; retries++) {
- if (advk_pcie_link_up(pcie)) {
- dev_info(dev, "link up\n");
+ if (advk_pcie_link_up(pcie))
return 0;
- }
usleep_range(LINK_WAIT_USLEEP_MIN, LINK_WAIT_USLEEP_MAX);
}
- dev_err(dev, "link never came up\n");
return -ETIMEDOUT;
}
@@ -253,10 +252,115 @@ static void advk_pcie_wait_for_retrain(struct advk_pcie *pcie)
}
}
+static int advk_pcie_train_at_gen(struct advk_pcie *pcie, int gen)
+{
+ int ret, neg_gen;
+ u32 reg;
+
+ /* Setup link speed */
+ reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG);
+ reg &= ~PCIE_GEN_SEL_MSK;
+ if (gen == 3)
+ reg |= SPEED_GEN_3;
+ else if (gen == 2)
+ reg |= SPEED_GEN_2;
+ else
+ reg |= SPEED_GEN_1;
+ advk_writel(pcie, reg, PCIE_CORE_CTRL0_REG);
+
+ /*
+ * Enable link training. This is not needed in every call to this
+ * function, just once suffices, but it does not break anything either.
+ */
+ reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG);
+ reg |= LINK_TRAINING_EN;
+ advk_writel(pcie, reg, PCIE_CORE_CTRL0_REG);
+
+ /*
+ * Start link training immediately after enabling it.
+ * This solves problems for some buggy cards.
+ */
+ reg = advk_readl(pcie, PCIE_CORE_PCIEXP_CAP + PCI_EXP_LNKCTL);
+ reg |= PCI_EXP_LNKCTL_RL;
+ advk_writel(pcie, reg, PCIE_CORE_PCIEXP_CAP + PCI_EXP_LNKCTL);
+
+ ret = advk_pcie_wait_for_link(pcie);
+ if (ret)
+ return ret;
+
+ reg = advk_read16(pcie, PCIE_CORE_PCIEXP_CAP + PCI_EXP_LNKSTA);
+ neg_gen = reg & PCI_EXP_LNKSTA_CLS;
+
+ return neg_gen;
+}
+
+static void advk_pcie_train_link(struct advk_pcie *pcie)
+{
+ struct device *dev = &pcie->pdev->dev;
+ int neg_gen = -1, gen;
+
+ /*
+ * Try link training at link gen specified by device tree property
+ * 'max-link-speed'. If this fails, iteratively train at lower gen.
+ */
+ for (gen = pcie->link_gen; gen > 0; --gen) {
+ neg_gen = advk_pcie_train_at_gen(pcie, gen);
+ if (neg_gen > 0)
+ break;
+ }
+
+ if (neg_gen < 0)
+ goto err;
+
+ /*
+ * After successful training if negotiated gen is lower than requested,
+ * train again on negotiated gen. This solves some stability issues for
+ * some buggy gen1 cards.
+ */
+ if (neg_gen < gen) {
+ gen = neg_gen;
+ neg_gen = advk_pcie_train_at_gen(pcie, gen);
+ }
+
+ if (neg_gen == gen) {
+ dev_info(dev, "link up at gen %i\n", gen);
+ return;
+ }
+
+err:
+ dev_err(dev, "link never came up\n");
+}
+
+static void advk_pcie_issue_perst(struct advk_pcie *pcie)
+{
+ u32 reg;
+
+ if (!pcie->reset_gpio)
+ return;
+
+ /* PERST does not work for some cards when link training is enabled */
+ reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG);
+ reg &= ~LINK_TRAINING_EN;
+ advk_writel(pcie, reg, PCIE_CORE_CTRL0_REG);
+
+ /* 10ms delay is needed for some cards */
+ dev_info(&pcie->pdev->dev, "issuing PERST via reset GPIO for 10ms\n");
+ gpiod_set_value_cansleep(pcie->reset_gpio, 1);
+ usleep_range(10000, 11000);
+ gpiod_set_value_cansleep(pcie->reset_gpio, 0);
+}
+
static void advk_pcie_setup_hw(struct advk_pcie *pcie)
{
u32 reg;
+ advk_pcie_issue_perst(pcie);
+
+ /* Enable TX */
+ reg = advk_readl(pcie, PCIE_CORE_REF_CLK_REG);
+ reg |= PCIE_CORE_REF_CLK_TX_ENABLE;
+ advk_writel(pcie, reg, PCIE_CORE_REF_CLK_REG);
+
/* Set to Direct mode */
reg = advk_readl(pcie, CTRL_CONFIG_REG);
reg &= ~(CTRL_MODE_MASK << CTRL_MODE_SHIFT);
@@ -275,36 +379,26 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie)
PCIE_CORE_ERR_CAPCTL_ECRC_CHCK_RCV;
advk_writel(pcie, reg, PCIE_CORE_ERR_CAPCTL_REG);
- /* Set PCIe Device Control and Status 1 PF0 register */
- reg = PCIE_CORE_DEV_CTRL_STATS_RELAX_ORDER_DISABLE |
- (7 << PCIE_CORE_DEV_CTRL_STATS_MAX_PAYLOAD_SZ_SHIFT) |
- PCIE_CORE_DEV_CTRL_STATS_SNOOP_DISABLE |
- (PCIE_CORE_DEV_CTRL_STATS_MAX_RD_REQ_SZ <<
- PCIE_CORE_DEV_CTRL_STATS_MAX_RD_REQ_SIZE_SHIFT);
- advk_writel(pcie, reg, PCIE_CORE_DEV_CTRL_STATS_REG);
+ /* Set PCIe Device Control register */
+ reg = advk_readl(pcie, PCIE_CORE_PCIEXP_CAP + PCI_EXP_DEVCTL);
+ reg &= ~PCI_EXP_DEVCTL_RELAX_EN;
+ reg &= ~PCI_EXP_DEVCTL_NOSNOOP_EN;
+ reg &= ~PCI_EXP_DEVCTL_READRQ;
+ reg |= PCI_EXP_DEVCTL_PAYLOAD; /* Set max payload size */
+ reg |= PCI_EXP_DEVCTL_READRQ_512B;
+ advk_writel(pcie, reg, PCIE_CORE_PCIEXP_CAP + PCI_EXP_DEVCTL);
/* Program PCIe Control 2 to disable strict ordering */
reg = PCIE_CORE_CTRL2_RESERVED |
PCIE_CORE_CTRL2_TD_ENABLE;
advk_writel(pcie, reg, PCIE_CORE_CTRL2_REG);
- /* Set GEN2 */
- reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG);
- reg &= ~PCIE_GEN_SEL_MSK;
- reg |= SPEED_GEN_2;
- advk_writel(pcie, reg, PCIE_CORE_CTRL0_REG);
-
/* Set lane X1 */
reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG);
reg &= ~LANE_CNT_MSK;
reg |= LANE_COUNT_1;
advk_writel(pcie, reg, PCIE_CORE_CTRL0_REG);
- /* Enable link training */
- reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG);
- reg |= LINK_TRAINING_EN;
- advk_writel(pcie, reg, PCIE_CORE_CTRL0_REG);
-
/* Enable MSI */
reg = advk_readl(pcie, PCIE_CORE_CTRL2_REG);
reg |= PCIE_CORE_CTRL2_MSI_ENABLE;
@@ -340,23 +434,22 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie)
/*
* PERST# signal could have been asserted by pinctrl subsystem before
- * probe() callback has been called, making the endpoint going into
+ * probe() callback has been called or issued explicitly by reset gpio
+ * function advk_pcie_issue_perst(), making the endpoint going into
* fundamental reset. As required by PCI Express spec a delay for at
* least 100ms after such a reset before link training is needed.
*/
msleep(PCI_PM_D3COLD_WAIT);
- /* Start link training */
- reg = advk_readl(pcie, PCIE_CORE_LINK_CTRL_STAT_REG);
- reg |= PCIE_CORE_LINK_TRAINING;
- advk_writel(pcie, reg, PCIE_CORE_LINK_CTRL_STAT_REG);
-
- advk_pcie_wait_for_link(pcie);
-
- reg = PCIE_CORE_LINK_L0S_ENTRY |
- (1 << PCIE_CORE_LINK_WIDTH_SHIFT);
- advk_writel(pcie, reg, PCIE_CORE_LINK_CTRL_STAT_REG);
+ advk_pcie_train_link(pcie);
+ /*
+ * FIXME: The following register update is suspicious. This register is
+ * applicable only when the PCI controller is configured for Endpoint
+ * mode, not as a Root Complex. But apparently when this code is
+ * removed, some cards stop working. This should be investigated and
+ * a comment explaining this should be put here.
+ */
reg = advk_readl(pcie, PCIE_CORE_CMD_STATUS_REG);
reg |= PCIE_CORE_CMD_MEM_ACCESS_EN |
PCIE_CORE_CMD_IO_ACCESS_EN |
@@ -952,6 +1045,62 @@ static irqreturn_t advk_pcie_irq_handler(int irq, void *arg)
return IRQ_HANDLED;
}
+static void __maybe_unused advk_pcie_disable_phy(struct advk_pcie *pcie)
+{
+ phy_power_off(pcie->phy);
+ phy_exit(pcie->phy);
+}
+
+static int advk_pcie_enable_phy(struct advk_pcie *pcie)
+{
+ int ret;
+
+ if (!pcie->phy)
+ return 0;
+
+ ret = phy_init(pcie->phy);
+ if (ret)
+ return ret;
+
+ ret = phy_set_mode(pcie->phy, PHY_MODE_PCIE);
+ if (ret) {
+ phy_exit(pcie->phy);
+ return ret;
+ }
+
+ ret = phy_power_on(pcie->phy);
+ if (ret) {
+ phy_exit(pcie->phy);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int advk_pcie_setup_phy(struct advk_pcie *pcie)
+{
+ struct device *dev = &pcie->pdev->dev;
+ struct device_node *node = dev->of_node;
+ int ret = 0;
+
+ pcie->phy = devm_of_phy_get(dev, node, NULL);
+ if (IS_ERR(pcie->phy) && (PTR_ERR(pcie->phy) == -EPROBE_DEFER))
+ return PTR_ERR(pcie->phy);
+
+ /* Old bindings miss the PHY handle */
+ if (IS_ERR(pcie->phy)) {
+ dev_warn(dev, "PHY unavailable (%ld)\n", PTR_ERR(pcie->phy));
+ pcie->phy = NULL;
+ return 0;
+ }
+
+ ret = advk_pcie_enable_phy(pcie);
+ if (ret)
+ dev_err(dev, "Failed to initialize PHY (%d)\n", ret);
+
+ return ret;
+}
+
static int advk_pcie_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@@ -992,6 +1141,32 @@ static int advk_pcie_probe(struct platform_device *pdev)
}
pcie->root_bus_nr = bus->start;
+ pcie->reset_gpio = devm_gpiod_get_from_of_node(dev, dev->of_node,
+ "reset-gpios", 0,
+ GPIOD_OUT_LOW,
+ "pcie1-reset");
+ ret = PTR_ERR_OR_ZERO(pcie->reset_gpio);
+ if (ret) {
+ if (ret == -ENOENT) {
+ pcie->reset_gpio = NULL;
+ } else {
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "Failed to get reset-gpio: %i\n",
+ ret);
+ return ret;
+ }
+ }
+
+ ret = of_pci_get_max_link_speed(dev->of_node);
+ if (ret <= 0 || ret > 3)
+ pcie->link_gen = 3;
+ else
+ pcie->link_gen = ret;
+
+ ret = advk_pcie_setup_phy(pcie);
+ if (ret)
+ return ret;
+
advk_pcie_setup_hw(pcie);
advk_sw_pci_bridge_init(pcie);
diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 81ceeaa6f1d5..27839cd2459f 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -592,7 +592,7 @@ int of_pci_get_max_link_speed(struct device_node *node)
u32 max_link_speed;
if (of_property_read_u32(node, "max-link-speed", &max_link_speed) ||
- max_link_speed > 4)
+ max_link_speed == 0 || max_link_speed > 4)
return -EINVAL;
return max_link_speed;