[”PATCH” 2/5] PCI: armada8k: Add link-down handle

[bpeled]

From: Ben Peled <bpe...@marvell.com>

In PCIE ISR routine caused by RST_LINK_DOWN
we schedule work to handle the link-down procedure.
Link-down procedure will:
1. Remove PCIe bus
2. Reset the MAC
3. Reconfigure link back up
4. Rescan PCIe bus

Signed-off-by: Ben Peled <bpe...@marvell.com>
---
 drivers/pci/controller/dwc/pcie-armada8k.c | 68 ++++++++++++++++++++
 1 file changed, 68 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-armada8k.c 
b/drivers/pci/controller/dwc/pcie-armada8k.c
index b2278b1..4eb8607 100644
--- a/drivers/pci/controller/dwc/pcie-armada8k.c
+++ b/drivers/pci/controller/dwc/pcie-armada8k.c
@@ -22,6 +22,8 @@
 #include <linux/resource.h>
 #include <linux/of_pci.h>
 #include <linux/of_irq.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
 
 #include "pcie-designware.h"
 
@@ -33,6 +35,9 @@ struct armada8k_pcie {
        struct clk *clk_reg;
        struct phy *phy[ARMADA8K_PCIE_MAX_LANES];
        unsigned int phy_count;
+       struct regmap *sysctrl_base;
+       u32 mac_rest_bitmask;
+       struct work_struct recover_link_work;
 };
 
 #define PCIE_VENDOR_REGS_OFFSET                0x8000
@@ -73,6 +78,8 @@ struct armada8k_pcie {
 #define AX_USER_DOMAIN_MASK            0x3
 #define AX_USER_DOMAIN_SHIFT           4
 
+#define UNIT_SOFT_RESET_CONFIG_REG     0x268
+
 #define to_armada8k_pcie(x)    dev_get_drvdata((x)->dev)
 
 static void armada8k_pcie_disable_phys(struct armada8k_pcie *pcie)
@@ -224,6 +231,49 @@ static int armada8k_pcie_host_init(struct pcie_port *pp)
 
        return 0;
 }
+static void armada8k_pcie_recover_link(struct work_struct *ws)
+{
+       struct armada8k_pcie *pcie = container_of(ws, struct armada8k_pcie, 
recover_link_work);
+       struct pcie_port *pp = &pcie->pci->pp;
+       struct pci_bus *bus = pp->bridge->bus;
+       struct pci_dev *root_port;
+       int ret;
+
+       root_port = pci_get_slot(bus, 0);
+       if (!root_port) {
+               dev_err(pcie->pci->dev, "failed to get root port\n");
+               return;
+       }
+       pci_lock_rescan_remove();
+       pci_stop_and_remove_bus_device(root_port);
+       /*
+        * Sleep needed to make sure all pcie transactions and access
+        * are flushed before resetting the mac
+        */
+       msleep(100);
+
+       /* Reset mac */
+       regmap_update_bits_base(pcie->sysctrl_base, UNIT_SOFT_RESET_CONFIG_REG,
+                               pcie->mac_rest_bitmask, 0, NULL, false, true);
+       udelay(1);
+       regmap_update_bits_base(pcie->sysctrl_base, UNIT_SOFT_RESET_CONFIG_REG,
+                               pcie->mac_rest_bitmask, pcie->mac_rest_bitmask,
+                               NULL, false, true);
+       udelay(1);
+       ret = armada8k_pcie_host_init(pp);
+       if (ret) {
+               dev_err(pcie->pci->dev, "failed to initialize host: %d\n", ret);
+               pci_unlock_rescan_remove();
+               pci_dev_put(root_port);
+               return;
+       }
+
+       bus = NULL;
+       while ((bus = pci_find_next_bus(bus)) != NULL)
+               pci_rescan_bus(bus);
+       pci_unlock_rescan_remove();
+       pci_dev_put(root_port);
+}
 
 static irqreturn_t armada8k_pcie_irq_handler(int irq, void *arg)
 {
@@ -262,6 +312,9 @@ static irqreturn_t armada8k_pcie_irq_handler(int irq, void 
*arg)
                 * initiate a link retrain. If link retrains were
                 * possible, that is.
                 */
+               if (pcie->sysctrl_base && pcie->mac_rest_bitmask)
+                       schedule_work(&pcie->recover_link_work);
+
                dev_dbg(pci->dev, "%s: link went down\n", __func__);
        }
 
@@ -330,6 +383,8 @@ static int armada8k_pcie_probe(struct platform_device *pdev)
 
        pcie->pci = pci;
 
+       INIT_WORK(&pcie->recover_link_work, armada8k_pcie_recover_link);
+
        pcie->clk = devm_clk_get(dev, NULL);
        if (IS_ERR(pcie->clk))
                return PTR_ERR(pcie->clk);
@@ -357,6 +412,19 @@ static int armada8k_pcie_probe(struct platform_device 
*pdev)
                goto fail_clkreg;
        }
 
+       pcie->sysctrl_base = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
+                                                      
"marvell,system-controller");
+       if (IS_ERR(pcie->sysctrl_base)) {
+               dev_warn(dev, "failed to find marvell,system-controller\n");
+               pcie->sysctrl_base = 0x0;
+       }
+
+       ret = of_property_read_u32(pdev->dev.of_node, 
"marvell,mac-reset-bit-mask",
+                                  &pcie->mac_rest_bitmask);
+       if (ret < 0) {
+               dev_warn(dev, "couldn't find mac reset bit mask: %d\n", ret);
+               pcie->mac_rest_bitmask = 0x0;
+       }
        ret = armada8k_pcie_setup_phys(pcie);
        if (ret)
                goto fail_clkreg;
-- 
2.7.4