[PATCH 4.14 20/41] PCI: dwc: Fix scheduling while atomic issues - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	Jisheng Zhang <Jisheng.Zhang@synaptics.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
	Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.14 20/41] PCI: dwc: Fix scheduling while atomic issues
Date: Thu, 18 Oct 2018 19:54:35 +0200	[thread overview]
Message-ID: <20181018175420.289225862@linuxfoundation.org> (raw)
In-Reply-To: <20181018175416.718399607@linuxfoundation.org>

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>

[ Upstream commit 9024143e700f89d74b8cdaf316a3499d74fc56fe ]

When programming the inbound/outbound ATUs, we call usleep_range() after
each checking PCIE_ATU_ENABLE bit. Unfortunately, the ATU programming
can be executed in atomic context:

inbound ATU programming could be called through
pci_epc_write_header()
  =>dw_pcie_ep_write_header()
    =>dw_pcie_prog_inbound_atu()

outbound ATU programming could be called through
pci_bus_read_config_dword()
  =>dw_pcie_rd_conf()
    =>dw_pcie_prog_outbound_atu()

Fix this issue by calling mdelay() instead.

Fixes: f8aed6ec624f ("PCI: dwc: designware: Add EP mode support")
Fixes: d8bbeb39fbf3 ("PCI: designware: Wait for iATU enable")
Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
[lorenzo.pieralisi@arm.com: commit log update]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/pci/dwc/pcie-designware.c |    8 ++++----
 drivers/pci/dwc/pcie-designware.h |    3 +--
 2 files changed, 5 insertions(+), 6 deletions(-)

--- a/drivers/pci/dwc/pcie-designware.c
+++ b/drivers/pci/dwc/pcie-designware.c
@@ -138,7 +138,7 @@ static void dw_pcie_prog_outbound_atu_un
 		if (val & PCIE_ATU_ENABLE)
 			return;
 
-		usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);
+		mdelay(LINK_WAIT_IATU);
 	}
 	dev_err(pci->dev, "outbound iATU is not being enabled\n");
 }
@@ -181,7 +181,7 @@ void dw_pcie_prog_outbound_atu(struct dw
 		if (val & PCIE_ATU_ENABLE)
 			return;
 
-		usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);
+		mdelay(LINK_WAIT_IATU);
 	}
 	dev_err(pci->dev, "outbound iATU is not being enabled\n");
 }
@@ -239,7 +239,7 @@ static int dw_pcie_prog_inbound_atu_unro
 		if (val & PCIE_ATU_ENABLE)
 			return 0;
 
-		usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);
+		mdelay(LINK_WAIT_IATU);
 	}
 	dev_err(pci->dev, "inbound iATU is not being enabled\n");
 
@@ -285,7 +285,7 @@ int dw_pcie_prog_inbound_atu(struct dw_p
 		if (val & PCIE_ATU_ENABLE)
 			return 0;
 
-		usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);
+		mdelay(LINK_WAIT_IATU);
 	}
 	dev_err(pci->dev, "inbound iATU is not being enabled\n");
 
--- a/drivers/pci/dwc/pcie-designware.h
+++ b/drivers/pci/dwc/pcie-designware.h
@@ -28,8 +28,7 @@
 
 /* Parameters for the waiting for iATU enabled routine */
 #define LINK_WAIT_MAX_IATU_RETRIES	5
-#define LINK_WAIT_IATU_MIN		9000
-#define LINK_WAIT_IATU_MAX		10000
+#define LINK_WAIT_IATU			9
 
 /* Synopsys-specific PCIe configuration registers */
 #define PCIE_PORT_LINK_CONTROL		0x710


