[PATCH v3 1/6] PCI: mediatek: Using readl_poll_timeout to wait Gen2 training

From: honghui.zhang
Date: Fri Aug 04 2017 - 08:12:16 EST


From: Ryder Lee <ryder.lee@xxxxxxxxxxxx>

Wait Gen2 training by using readl_poll_timeout() calls, and simplify
the hardware assert logical by merge it into the new interface
mtk_pcie_startup_ports.

Signed-off-by: Ryder Lee <ryder.lee@xxxxxxxxxxxx>
Signed-off-by: Honghui Zhang <honghui.zhang@xxxxxxxxxxxx>
---
drivers/pci/host/pcie-mediatek.c | 52 +++++++++++++++++-----------------------
1 file changed, 22 insertions(+), 30 deletions(-)

diff --git a/drivers/pci/host/pcie-mediatek.c b/drivers/pci/host/pcie-mediatek.c
index 9c9f89b..0d46cda 100644
--- a/drivers/pci/host/pcie-mediatek.c
+++ b/drivers/pci/host/pcie-mediatek.c
@@ -16,6 +16,7 @@

#include <linux/clk.h>
#include <linux/delay.h>
+#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/of_address.h>
#include <linux/of_pci.h>
@@ -113,11 +114,6 @@ struct mtk_pcie {
struct list_head ports;
};

-static inline bool mtk_pcie_link_up(struct mtk_pcie_port *port)
-{
- return !!(readl(port->base + PCIE_LINK_STATUS) & PCIE_PORT_LINKUP);
-}
-
static void mtk_pcie_subsys_powerdown(struct mtk_pcie *pcie)
{
struct device *dev = pcie->dev;
@@ -171,12 +167,30 @@ static struct pci_ops mtk_pcie_ops = {
.write = pci_generic_config_write,
};

-static void mtk_pcie_configure_rc(struct mtk_pcie_port *port)
+static int mtk_pcie_startup_ports(struct mtk_pcie_port *port)
{
struct mtk_pcie *pcie = port->pcie;
u32 func = PCI_FUNC(port->index << 3);
u32 slot = PCI_SLOT(port->index << 3);
u32 val;
+ int err;
+
+ /* assert port PERST_N */
+ val = readl(pcie->base + PCIE_SYS_CFG);
+ val |= PCIE_PORT_PERST(port->index);
+ writel(val, pcie->base + PCIE_SYS_CFG);
+
+ /* de-assert port PERST_N */
+ val = readl(pcie->base + PCIE_SYS_CFG);
+ val &= ~PCIE_PORT_PERST(port->index);
+ writel(val, pcie->base + PCIE_SYS_CFG);
+
+ /* 100ms timeout value should be enough for Gen1/2 training */
+ err = readl_poll_timeout(port->base + PCIE_LINK_STATUS, val,
+ !!(val & PCIE_PORT_LINKUP), 20,
+ 100 * USEC_PER_MSEC);
+ if (err)
+ return -ETIMEDOUT;

/* enable interrupt */
val = readl(pcie->base + PCIE_INT_ENABLE);
@@ -209,25 +223,8 @@ static void mtk_pcie_configure_rc(struct mtk_pcie_port *port)
writel(PCIE_CONF_ADDR(PCIE_FTS_NUM, func, slot, 0),
pcie->base + PCIE_CFG_ADDR);
writel(val, pcie->base + PCIE_CFG_DATA);
-}

-static void mtk_pcie_assert_ports(struct mtk_pcie_port *port)
-{
- struct mtk_pcie *pcie = port->pcie;
- u32 val;
-
- /* assert port PERST_N */
- val = readl(pcie->base + PCIE_SYS_CFG);
- val |= PCIE_PORT_PERST(port->index);
- writel(val, pcie->base + PCIE_SYS_CFG);
-
- /* de-assert port PERST_N */
- val = readl(pcie->base + PCIE_SYS_CFG);
- val &= ~PCIE_PORT_PERST(port->index);
- writel(val, pcie->base + PCIE_SYS_CFG);
-
- /* PCIe v2.0 need at least 100ms delay to train from Gen1 to Gen2 */
- msleep(100);
+ return 0;
}

static void mtk_pcie_enable_ports(struct mtk_pcie_port *port)
@@ -250,13 +247,8 @@ static void mtk_pcie_enable_ports(struct mtk_pcie_port *port)
goto err_phy_on;
}

- mtk_pcie_assert_ports(port);
-
- /* if link up, then setup root port configuration space */
- if (mtk_pcie_link_up(port)) {
- mtk_pcie_configure_rc(port);
+ if (!mtk_pcie_startup_ports(port))
return;
- }

dev_info(dev, "Port%d link down\n", port->index);

--
2.6.4