[PATCH v8 02/24] PCI: Ensure a bridge has I/O and MEM access for hot-added devices

From: Sergei Miroshnichenko <s.miroshnichenko@yadro.com>
To: <linux-pci@vger.kernel.org>
Cc: "Bjorn Helgaas" <helgaas@kernel.org>,
	"Lukas Wunner" <lukas@wunner.de>, "Stefan Roese" <sr@denx.de>,
	"Andy Lavr" <andy.lavr@gmail.com>,
	"Christian König" <christian.koenig@amd.com>,
	"Ard Biesheuvel" <ardb@kernel.org>,
	"David Laight" <David.Laight@ACULAB.COM>,
	"Rajat Jain" <rajatja@google.com>,
	linux@yadro.com,
	"Sergei Miroshnichenko" <s.miroshnichenko@yadro.com>
Subject: [PATCH v8 02/24] PCI: Ensure a bridge has I/O and MEM access for hot-added devices
Date: Mon, 27 Apr 2020 21:23:36 +0300	[thread overview]
Message-ID: <20200427182358.2067702-3-s.miroshnichenko@yadro.com> (raw)
In-Reply-To: <20200427182358.2067702-1-s.miroshnichenko@yadro.com>

During hot-adding a device, its bridge may be already pci_is_enabled(), but
without the I/O and/or MEM access bits, which may be required by this new
device: these bits are set during first enabling the bridge, and they must
be checked again.

When hot-adding to the following bridge:

  +-[0020:00]---00.0-[01-0d]----00.0-[02-0d]----04.0-[03-0d]--   <-   00.0

this patch sets up the MEM bit in the downstream port 0020:02:04.0, needed
for 0020:08:00.0:

  [ 1037.698206] pci 0020:00:00.0: PCI bridge to [bus 01-0d]
  [ 1037.698785] pci 0020:00:00.0:   bridge window [mem 0x3fe800000000-0x3fe8017fffff]
  [ 1037.698874] pci 0020:00:00.0:   bridge window [mem 0x240000000000-0x2400ffffffff 64bit pref]
  [ 1037.699002] pcieport 0020:02:04.0: enabling device (0545 -> 0547)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  [ 1037.699114] pcieport 0020:03:00.0: enabling device (0540 -> 0542)
  [ 1037.699198] pciehp 0020:04:09.0:pcie204: Slot #41 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise- Interlock- NoCompl- LLActRep+
  [ 1037.699285] pciehp 0020:04:09.0:pcie204: Slot(41): Card present
  [ 1037.699346] pciehp 0020:04:09.0:pcie204: Slot(41): Already enabled

Signed-off-by: Sergei Miroshnichenko <s.miroshnichenko@yadro.com>
---
 drivers/pci/pci.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index d7819be809a3..2c0ae81d260d 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1740,6 +1740,8 @@ static void pci_enable_bridge(struct pci_dev *dev)
 		pci_enable_bridge(bridge);
 
 	if (pci_is_enabled(dev)) {
+		pci_reenable_device(dev);
+
 		if (!dev->is_busmaster)
 			pci_set_master(dev);
 		mutex_unlock(&dev->enable_mutex);
-- 
2.24.1

