From: Stanislav Spassov <stanspas@amazon.com>
To: <linux-pci@vger.kernel.org>
Cc: "Stanislav Spassov" <stanspas@amazon.de>,
linux-acpi@vger.kernel.org, "Bjorn Helgaas" <bhelgaas@google.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Jan H . Schönherr" <jschoenh@amazon.de>,
"Jonathan Corbet" <corbet@lwn.net>,
"Ashok Raj" <ashok.raj@intel.com>,
"Alex Williamson" <alex.williamson@redhat.com>,
"Sinan Kaya" <okaya@kernel.org>,
"Rajat Jain" <rajatja@google.com>,
"kbuild test robot" <lkp@intel.com>
Subject: [PATCH v3 15/17] PCI: Refactor polling loop out of pci_dev_wait
Date: Tue, 3 Mar 2020 14:28:50 +0100 [thread overview]
Message-ID: <20200303132852.13184-16-stanspas@amazon.com> (raw)
In-Reply-To: <20200303132852.13184-1-stanspas@amazon.com>
From: Stanislav Spassov <stanspas@amazon.de>
This patch does not (intentionally) introduce any observable difference
in runtime behavior.
Signed-off-by: Stanislav Spassov <stanspas@amazon.de>
---
drivers/pci/pci.c | 71 +++++++++++++++++++++++++++++++++--------------
1 file changed, 50 insertions(+), 21 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e81fd3b53bd0..f1ba931b0ead 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1027,27 +1027,28 @@ void pci_wakeup_bus(struct pci_bus *bus)
pci_walk_bus(bus, pci_wakeup, NULL);
}
-static int pci_dev_wait(struct pci_dev *dev, enum pci_init_event event)
+/*
+ * Performs DWORD Configuration Reads at a specific offset until the value read
+ * (with mask applied) is not equal to bad_value.
+ */
+static inline int pci_dev_poll_until_not_equal(struct pci_dev *dev, int where,
+ u32 mask, u32 bad_value,
+ const char *event_name,
+ int timeout, int *waited,
+ u32 *final_value)
{
- const char *event_name = pci_init_event_name(event);
- int timeout = dev->reset_ready_poll_ms;
int delay = 1;
- u32 id;
+ u32 value;
- /*
- * After reset, the device should not silently discard config
- * requests, but it may still indicate that it needs more time by
- * responding to them with CRS completions. The Root Port will
- * generally synthesize ~0 data to complete the read (except when
- * CRS SV is enabled and the read was for the Vendor ID; in that
- * case it synthesizes 0x0001 data).
- *
- * Wait for the device to return a non-CRS completion. Read the
- * Command register instead of Vendor ID so we don't have to
- * contend with the CRS SV value.
- */
- pci_read_config_dword(dev, PCI_COMMAND, &id);
- while (id == ~0) {
+ if (!event_name)
+ event_name = "<unknown event>";
+
+ if (waited)
+ delay = *waited + 1;
+
+ pci_read_config_dword(dev, where, &value);
+
+ while ((value & mask) == bad_value) {
if (delay > timeout) {
pci_warn(dev, "not ready %dms after %s; giving up\n",
delay - 1, event_name);
@@ -1060,16 +1061,44 @@ static int pci_dev_wait(struct pci_dev *dev, enum pci_init_event event)
msleep(delay);
delay *= 2;
- pci_read_config_dword(dev, PCI_COMMAND, &id);
+
+ pci_read_config_dword(dev, where, &value);
}
if (delay > 1000)
- pci_info(dev, "ready %dms after %s\n", delay - 1,
- event_name);
+ pci_info(dev, "ready %dms after %s\n", delay - 1, event_name);
+
+ if (waited)
+ *waited = delay - 1;
+
+ if (final_value)
+ *final_value = value;
return 0;
}
+static int pci_dev_wait(struct pci_dev *dev, enum pci_init_event event)
+{
+ const char *event_name = pci_init_event_name(event);
+ int timeout = dev->reset_ready_poll_ms;
+
+ /*
+ * After reset, the device should not silently discard config
+ * requests, but it may still indicate that it needs more time by
+ * responding to them with CRS completions. The Root Port will
+ * generally synthesize ~0 data to complete the read (except when
+ * CRS SV is enabled and the read was for the Vendor ID; in that
+ * case it synthesizes 0x0001 data).
+ *
+ * Wait for the device to return a non-CRS completion. Read the
+ * Command register instead of Vendor ID so we don't have to
+ * contend with the CRS SV value.
+ */
+ return pci_dev_poll_until_not_equal(dev, PCI_COMMAND, ~0, ~0,
+ event_name, timeout, NULL,
+ NULL);
+}
+
/**
* pci_power_up - Put the given device into D0
* @dev: PCI device to power up
--
2.25.1
Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879
next prev parent reply other threads:[~2020-03-03 13:31 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-03 13:28 [PATCH v3 00/17] Improve PCI device post-reset readiness polling Stanislav Spassov
2020-03-03 13:28 ` [PATCH v3 01/17] PCI: Fall back to slot/bus reset if softer methods timeout Stanislav Spassov
2020-03-03 13:28 ` [PATCH v3 02/17] PCI: Remove unused PCI_PM_BUS_WAIT Stanislav Spassov
2020-03-03 13:28 ` [PATCH v3 03/17] PCI: Use pci_bridge_wait_for_secondary_bus after SBR Stanislav Spassov
2020-03-03 13:28 ` [PATCH v3 04/17] PCI: Do not override delay for D0->D3hot transition Stanislav Spassov
2020-03-03 18:57 ` Rafael J. Wysocki
2020-03-07 10:58 ` Spassov, Stanislav
2020-03-03 13:28 ` [PATCH v3 05/17] PCI: Fix handling of _DSM 8 (avoiding reset delays) Stanislav Spassov
2020-03-03 13:28 ` [PATCH v3 06/17] PCI: Fix us->ms conversion in pci_acpi_optimize_delay Stanislav Spassov
2020-03-03 13:28 ` [PATCH v3 07/17] PCI: Clean up and document PM/reset delays Stanislav Spassov
2020-03-03 19:03 ` Rafael J. Wysocki
2020-03-07 11:30 ` Spassov, Stanislav
2020-03-03 13:28 ` [PATCH v3 08/17] PCI: Add more delay overrides to struct pci_dev Stanislav Spassov
2020-03-03 13:28 ` [PATCH v3 09/17] PCI: Generalize pci_bus_max_d3cold_delay to pci_bus_max_delay Stanislav Spassov
2020-03-03 13:28 ` [PATCH v3 10/17] PCI: Use correct delay in pci_bridge_wait_for_secondary_bus Stanislav Spassov
2020-03-03 13:28 ` [PATCH v3 11/17] PCI: Refactor pci_dev_wait to remove timeout parameter Stanislav Spassov
2020-03-03 13:28 ` [PATCH v3 12/17] PCI: Refactor pci_dev_wait to take pci_init_event Stanislav Spassov
2020-03-03 13:28 ` [PATCH v3 13/17] PCI: Cache CRS Software Visibiliy in struct pci_dev Stanislav Spassov
2020-03-03 13:28 ` [PATCH v3 14/17] PCI: Introduce per-device reset_ready_poll override Stanislav Spassov
2020-03-03 13:28 ` Stanislav Spassov [this message]
2020-03-03 13:28 ` [PATCH v3 16/17] PCI: Add CRS handling to pci_dev_wait() Stanislav Spassov
2020-03-05 17:56 ` Raj, Ashok
2020-03-06 18:07 ` Spassov, Stanislav
2020-03-03 13:28 ` [PATCH v3 17/17] PCI: Lower PCIE_RESET_READY_POLL_MS from 1m to 1s Stanislav Spassov
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