[PATCH v11 2/4] PCI: designware: Add generic dw_pcie_wait_for_link()

From: Bjorn Helgaas
Date: Fri Feb 26 2016 - 11:30:21 EST

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From: Joao Pinto <Joao.Pinto@xxxxxxxxxxxx>

Several DesignWare-based drivers (dra7xx, exynos, imx6, keystone, qcom, and
spear13xx) had similar loops waiting for the link to come up.

Add a generic dw_pcie_wait_for_link() for use by all these drivers so the
waiting is done consistently, e.g., always using usleep_range() rather than
mdelay() and using similar timeouts and retry counts.

Note that this changes the Keystone link training/wait for link strategy,
so we initiate link training, then wait longer for the link to come up
before re-initiating link training.

[bhelgaas: changelog, split into its own patch, update pci-keystone.c, pcie-qcom.c]
Signed-off-by: Joao Pinto <jpinto@xxxxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
drivers/pci/host/pci-dra7xx.c | 11 +----------
drivers/pci/host/pci-exynos.c | 13 +++----------
drivers/pci/host/pci-imx6.c | 13 ++++---------
drivers/pci/host/pci-keystone.c | 10 ++++------
drivers/pci/host/pcie-designware.c | 19 +++++++++++++++++++
drivers/pci/host/pcie-designware.h | 6 ++++++
drivers/pci/host/pcie-qcom.c | 10 +---------
drivers/pci/host/pcie-spear13xx.c | 14 +-------------
8 files changed, 39 insertions(+), 57 deletions(-)

diff --git a/drivers/pci/host/pci-dra7xx.c b/drivers/pci/host/pci-dra7xx.c
index 923607b..2ca3a1f 100644
--- a/drivers/pci/host/pci-dra7xx.c
+++ b/drivers/pci/host/pci-dra7xx.c
@@ -10,7 +10,6 @@
* published by the Free Software Foundation.
*/

-#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
@@ -108,7 +107,6 @@ static int dra7xx_pcie_establish_link(struct pcie_port *pp)
{
struct dra7xx_pcie *dra7xx = to_dra7xx_pcie(pp);
u32 reg;
- unsigned int retries;

if (dw_pcie_link_up(pp)) {
dev_err(pp->dev, "link is already up\n");
@@ -119,14 +117,7 @@ static int dra7xx_pcie_establish_link(struct pcie_port *pp)
reg |= LTSSM_EN;
dra7xx_pcie_writel(dra7xx, PCIECTRL_DRA7XX_CONF_DEVICE_CMD, reg);

- for (retries = 0; retries < 1000; retries++) {
- if (dw_pcie_link_up(pp))
- return 0;
- usleep_range(10, 20);
- }
-
- dev_err(pp->dev, "link is not up\n");
- return -EINVAL;
+ return dw_pcie_wait_for_link(pp);
}

static void dra7xx_pcie_enable_interrupts(struct pcie_port *pp)
diff --git a/drivers/pci/host/pci-exynos.c b/drivers/pci/host/pci-exynos.c
index d997d22..2199761 100644
--- a/drivers/pci/host/pci-exynos.c
+++ b/drivers/pci/host/pci-exynos.c
@@ -318,7 +318,6 @@ static int exynos_pcie_establish_link(struct pcie_port *pp)
{
struct exynos_pcie *exynos_pcie = to_exynos_pcie(pp);
u32 val;
- unsigned int retries;

if (dw_pcie_link_up(pp)) {
dev_err(pp->dev, "Link already up\n");
@@ -357,13 +356,8 @@ static int exynos_pcie_establish_link(struct pcie_port *pp)
PCIE_APP_LTSSM_ENABLE);

/* check if the link is up or not */
- for (retries = 0; retries < 10; retries++) {
- if (dw_pcie_link_up(pp)) {
- dev_info(pp->dev, "Link up\n");
- return 0;
- }
- mdelay(100);
- }
+ if (!dw_pcie_wait_for_link(pp))
+ return 0;

while (exynos_phy_readl(exynos_pcie, PCIE_PHY_PLL_LOCKED) == 0) {
val = exynos_blk_readl(exynos_pcie, PCIE_PHY_PLL_LOCKED);
@@ -372,8 +366,7 @@ static int exynos_pcie_establish_link(struct pcie_port *pp)
/* power off phy */
exynos_pcie_power_off_phy(pp);

- dev_err(pp->dev, "PCIe Link Fail\n");
- return -EINVAL;
+ return -ETIMEDOUT;
}

static void exynos_pcie_clear_irq_pulse(struct pcie_port *pp)
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
index fe60096..6c35d86 100644
--- a/drivers/pci/host/pci-imx6.c
+++ b/drivers/pci/host/pci-imx6.c
@@ -330,19 +330,14 @@ static void imx6_pcie_init_phy(struct pcie_port *pp)

static int imx6_pcie_wait_for_link(struct pcie_port *pp)
{
- unsigned int retries;
-
- for (retries = 0; retries < 200; retries++) {
- if (dw_pcie_link_up(pp))
- return 0;
- usleep_range(100, 1000);
- }
+ /* check if the link is up or not */
+ if (!dw_pcie_wait_for_link(pp))
+ return 0;

- dev_err(pp->dev, "phy link never came up\n");
dev_dbg(pp->dev, "DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n",
readl(pp->dbi_base + PCIE_PHY_DEBUG_R0),
readl(pp->dbi_base + PCIE_PHY_DEBUG_R1));
- return -EINVAL;
+ return -ETIMEDOUT;
}

static int imx6_pcie_wait_for_speed_change(struct pcie_port *pp)
diff --git a/drivers/pci/host/pci-keystone.c b/drivers/pci/host/pci-keystone.c
index 0aa81bd..9a91487 100644
--- a/drivers/pci/host/pci-keystone.c
+++ b/drivers/pci/host/pci-keystone.c
@@ -97,17 +97,15 @@ static int ks_pcie_establish_link(struct keystone_pcie *ks_pcie)
return 0;
}

- ks_dw_pcie_initiate_link_train(ks_pcie);
/* check if the link is up or not */
- for (retries = 0; retries < 200; retries++) {
- if (dw_pcie_link_up(pp))
- return 0;
- usleep_range(100, 1000);
+ for (retries = 0; retries < 5; retries++) {
ks_dw_pcie_initiate_link_train(ks_pcie);
+ if (!dw_pcie_wait_for_link(pp))
+ return 0;
}

dev_err(pp->dev, "phy link never came up\n");
- return -EINVAL;
+ return -ETIMEDOUT;
}

static void ks_pcie_msi_irq_handler(struct irq_desc *desc)
diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
index 2171682..1fd3ad3 100644
--- a/drivers/pci/host/pcie-designware.c
+++ b/drivers/pci/host/pcie-designware.c
@@ -22,6 +22,7 @@
#include <linux/pci_regs.h>
#include <linux/platform_device.h>
#include <linux/types.h>
+#include <linux/delay.h>

#include "pcie-designware.h"

@@ -380,6 +381,24 @@ static struct msi_controller dw_pcie_msi_chip = {
.teardown_irq = dw_msi_teardown_irq,
};

+int dw_pcie_wait_for_link(struct pcie_port *pp)
+{
+ int retries;
+
+ /* check if the link is up or not */
+ for (retries = 0; retries < LINK_WAIT_MAX_RETRIES; retries++) {
+ if (dw_pcie_link_up(pp)) {
+ dev_info(pp->dev, "link up\n");
+ return 0;
+ }
+ usleep_range(LINK_WAIT_USLEEP_MIN, LINK_WAIT_USLEEP_MAX);
+ }
+
+ dev_err(pp->dev, "phy link never came up\n");
+
+ return -ETIMEDOUT;
+}
+
int dw_pcie_link_up(struct pcie_port *pp)
{
if (pp->ops->link_up)
diff --git a/drivers/pci/host/pcie-designware.h b/drivers/pci/host/pcie-designware.h
index 2356d29..f437f9b 100644
--- a/drivers/pci/host/pcie-designware.h
+++ b/drivers/pci/host/pcie-designware.h
@@ -22,6 +22,11 @@
#define MAX_MSI_IRQS 32
#define MAX_MSI_CTRLS (MAX_MSI_IRQS / 32)

+/* Parameters for the waiting for link up routine */
+#define LINK_WAIT_MAX_RETRIES 10
+#define LINK_WAIT_USLEEP_MIN 90000
+#define LINK_WAIT_USLEEP_MAX 100000
+
struct pcie_port {
struct device *dev;
u8 root_bus_nr;
@@ -76,6 +81,7 @@ int dw_pcie_cfg_read(void __iomem *addr, int size, u32 *val);
int dw_pcie_cfg_write(void __iomem *addr, int size, u32 val);
irqreturn_t dw_handle_msi_irq(struct pcie_port *pp);
void dw_pcie_msi_init(struct pcie_port *pp);
+int dw_pcie_wait_for_link(struct pcie_port *pp);
int dw_pcie_link_up(struct pcie_port *pp);
void dw_pcie_setup_rc(struct pcie_port *pp);
int dw_pcie_host_init(struct pcie_port *pp);
diff --git a/drivers/pci/host/pcie-qcom.c b/drivers/pci/host/pcie-qcom.c
index e845fba..ec4ef54 100644
--- a/drivers/pci/host/pcie-qcom.c
+++ b/drivers/pci/host/pcie-qcom.c
@@ -128,15 +128,7 @@ static int qcom_pcie_establish_link(struct qcom_pcie *pcie)
val |= PCIE20_ELBI_SYS_CTRL_LT_ENABLE;
writel(val, pcie->elbi + PCIE20_ELBI_SYS_CTRL);

- do {
- if (dw_pcie_link_up(&pcie->pp))
- return 0;
- usleep_range(250, 1000);
- } while (retries < 200);
-
- dev_warn(dev, "phy link never came up\n");
-
- return -ETIMEDOUT;
+ return dw_pcie_wait_for_link(pp);
}

static int qcom_pcie_get_resources_v0(struct qcom_pcie *pcie)
diff --git a/drivers/pci/host/pcie-spear13xx.c b/drivers/pci/host/pcie-spear13xx.c
index a6cd823..a4060b8 100644
--- a/drivers/pci/host/pcie-spear13xx.c
+++ b/drivers/pci/host/pcie-spear13xx.c
@@ -13,7 +13,6 @@
*/

#include <linux/clk.h>
-#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
@@ -149,7 +148,6 @@ static int spear13xx_pcie_establish_link(struct pcie_port *pp)
struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pp);
struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
u32 exp_cap_off = EXP_CAP_ID_OFFSET;
- unsigned int retries;

if (dw_pcie_link_up(pp)) {
dev_err(pp->dev, "link already up\n");
@@ -200,17 +198,7 @@ static int spear13xx_pcie_establish_link(struct pcie_port *pp)
| ((u32)1 << REG_TRANSLATION_ENABLE),
&app_reg->app_ctrl_0);

- /* check if the link is up or not */
- for (retries = 0; retries < 10; retries++) {
- if (dw_pcie_link_up(pp)) {
- dev_info(pp->dev, "link up\n");
- return 0;
- }
- mdelay(100);
- }
-
- dev_err(pp->dev, "link Fail\n");
- return -EINVAL;
+ return dw_pcie_wait_for_link(pp);
}

static irqreturn_t spear13xx_pcie_irq_handler(int irq, void *arg)

Next message: Bjorn Helgaas: "[PATCH v11 3/4] PCI: designware: Add default link up check if sub-driver doesn't override"
Previous message: Bjorn Helgaas: "[PATCH v11 1/4] ARC: Add PCI support"
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Next in thread: Pratyush Anand: "Re: [PATCH v11 2/4] PCI: designware: Add generic dw_pcie_wait_for_link()"
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