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From 199ff14100095d52cd1b232cc0f3b12f348b5b07 Mon Sep 17 00:00:00 2001
From: Ray Jui <rjui@broadcom.com>
Date: Tue, 15 Sep 2015 17:39:18 -0700
Subject: [PATCH 4/7] PCI: iproc: Fix PCIe reset logic
The current reset logic does not always properly reset the device. For
example, in the case when the perst_b signal is already de-asserted in the
bootloader, the current reset logic fails to trigger a proper assert ->
de-assert reset sequence.
Fix the issue by always triggering the proper reset sequence.
Also explicitly select the desired reset source, i.e., perst_b, and reduce
the wait time after the device comes out of reset from 250 ms to 100 ms,
based on recommendation from the ASIC team.
Tested-by: Vladimir Dreizin <vdreizin@broadcom.com>
Tested-by: Darren Edamura <dedamura@broadcom.com>
Signed-off-by: Ray Jui <rjui@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Vladimir Dreizin <vdreizin@broadcom.com>
Reviewed-by: Trac Hoang <trhoang@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
---
drivers/pci/host/pcie-iproc.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
--- a/drivers/pci/host/pcie-iproc.c
+++ b/drivers/pci/host/pcie-iproc.c
@@ -31,6 +31,8 @@
#include "pcie-iproc.h"
#define CLK_CONTROL_OFFSET 0x000
+#define EP_PERST_SOURCE_SELECT_SHIFT 2
+#define EP_PERST_SOURCE_SELECT BIT(EP_PERST_SOURCE_SELECT_SHIFT)
#define EP_MODE_SURVIVE_PERST_SHIFT 1
#define EP_MODE_SURVIVE_PERST BIT(EP_MODE_SURVIVE_PERST_SHIFT)
#define RC_PCIE_RST_OUTPUT_SHIFT 0
@@ -119,15 +121,18 @@ static void iproc_pcie_reset(struct ipro
u32 val;
/*
- * Configure the PCIe controller as root complex and send a downstream
- * reset
+ * Select perst_b signal as reset source. Put the device into reset,
+ * and then bring it out of reset
*/
- val = EP_MODE_SURVIVE_PERST | RC_PCIE_RST_OUTPUT;
+ val = readl(pcie->base + CLK_CONTROL_OFFSET);
+ val &= ~EP_PERST_SOURCE_SELECT & ~EP_MODE_SURVIVE_PERST &
+ ~RC_PCIE_RST_OUTPUT;
writel(val, pcie->base + CLK_CONTROL_OFFSET);
udelay(250);
- val &= ~EP_MODE_SURVIVE_PERST;
+
+ val |= RC_PCIE_RST_OUTPUT;
writel(val, pcie->base + CLK_CONTROL_OFFSET);
- msleep(250);
+ msleep(100);
}
static int iproc_pcie_check_link(struct iproc_pcie *pcie, struct pci_bus *bus)
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