@@ -40,6 +40,7 @@
#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_SPEED_SHIFT 16
#define PCIE_CORE_LINK_WIDTH_SHIFT 20
#define PCIE_CORE_ERR_CAPCTL_REG 0x118
#define PCIE_CORE_ERR_CAPCTL_ECRC_CHK_TX BIT(5)
@@ -201,6 +202,7 @@ struct advk_pcie {
struct mutex msi_used_lock;
u16 msi_msg;
int root_bus_nr;
+ int link_gen;
struct pci_bridge_emul bridge;
};
@@ -225,20 +227,16 @@ 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;
}
@@ -253,6 +251,85 @@ 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_LINK_CTRL_STAT_REG);
+ reg |= PCIE_CORE_LINK_TRAINING;
+ advk_writel(pcie, reg, PCIE_CORE_LINK_CTRL_STAT_REG);
+
+ ret = advk_pcie_wait_for_link(pcie);
+ if (ret)
+ return ret;
+
+ reg = advk_readl(pcie, PCIE_CORE_LINK_CTRL_STAT_REG);
+ neg_gen = (reg >> PCIE_CORE_LINK_SPEED_SHIFT) & 0xf;
+
+ 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_setup_hw(struct advk_pcie *pcie)
{
u32 reg;
@@ -288,12 +365,6 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie)
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;
@@ -341,20 +412,7 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie)
*/
msleep(PCI_PM_D3COLD_WAIT);
- /* Enable link training */
- 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_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);
+ advk_pcie_train_link(pcie);
reg = advk_readl(pcie, PCIE_CORE_CMD_STATUS_REG);
reg |= PCIE_CORE_CMD_MEM_ACCESS_EN |
@@ -988,6 +1046,12 @@ static int advk_pcie_probe(struct platform_device *pdev)
}
pcie->root_bus_nr = bus->start;
+ ret = of_pci_get_max_link_speed(dev->of_node);
+ if (ret <= 0 || ret > 3)
+ pcie->link_gen = 3;
+ else
+ pcie->link_gen = ret;
+
advk_pcie_setup_hw(pcie);
advk_sw_pci_bridge_init(pcie);