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107 lines
3.2 KiB
Diff
107 lines
3.2 KiB
Diff
From f2991d30ff590bf932483a6dfc16c7ebe2f83341 Mon Sep 17 00:00:00 2001
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From: Laurentiu Tudor <laurentiu.tudor@nxp.com>
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Date: Fri, 13 Apr 2018 12:42:40 +0300
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Subject: [PATCH] bus: fsl-mc: add device binding path 'driver_override'
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This patch is required for vfio-fsl-mc meta driver to successfully bind
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layerscape container devices for device passthrough. This patch adds
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a mechanism to allow a layerscape device to specify a driver rather than
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a layerscape driver provide a device match.
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This patch is based on following proposed patches for PCI and platform
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devices
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- https://lkml.org/lkml/2014/4/8/571 :- For Platform devices
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- http://lists-archives.com/linux-kernel/28030441-pci-introduce-new-device-binding-path-using-pci_dev-driver_override.html
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:- For PCI devices
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Example to allow a device (dprc.1) to specifically bind
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with driver (vfio-fsl-mc):-
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- echo vfio-fsl-mc > /sys/bus/fsl-mc/devices/dprc.1/driver_override
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- echo dprc.1 > /sys/bus/fsl-mc/drivers/fsl_mc_dprc/unbind
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- echo dprc.1 > /sys/bus/fsl-mc/drivers/vfio-fsl-mc/bind
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Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
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Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
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---
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drivers/bus/fsl-mc/fsl-mc-bus.c | 53 +++++++++++++++++++++++++++++++++++++++++
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1 file changed, 53 insertions(+)
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--- a/drivers/bus/fsl-mc/fsl-mc-bus.c
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+++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
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@@ -83,6 +83,12 @@ static int fsl_mc_bus_match(struct devic
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struct fsl_mc_driver *mc_drv = to_fsl_mc_driver(drv);
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bool found = false;
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+ /* When driver_override is set, only bind to the matching driver */
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+ if (mc_dev->driver_override) {
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+ found = !strcmp(mc_dev->driver_override, mc_drv->driver.name);
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+ goto out;
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+ }
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+
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if (!mc_drv->match_id_table)
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goto out;
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@@ -147,8 +153,52 @@ static ssize_t modalias_show(struct devi
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}
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static DEVICE_ATTR_RO(modalias);
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+static ssize_t driver_override_store(struct device *dev,
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+ struct device_attribute *attr,
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+ const char *buf, size_t count)
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+{
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+ struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
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+ const char *driver_override, *old = mc_dev->driver_override;
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+ char *cp;
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+
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+ if (WARN_ON(dev->bus != &fsl_mc_bus_type))
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+ return -EINVAL;
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+
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+ if (count >= (PAGE_SIZE - 1))
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+ return -EINVAL;
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+
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+ driver_override = kstrndup(buf, count, GFP_KERNEL);
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+ if (!driver_override)
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+ return -ENOMEM;
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+
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+ cp = strchr(driver_override, '\n');
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+ if (cp)
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+ *cp = '\0';
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+
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+ if (strlen(driver_override)) {
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+ mc_dev->driver_override = driver_override;
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+ } else {
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+ kfree(driver_override);
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+ mc_dev->driver_override = NULL;
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+ }
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+
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+ kfree(old);
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+
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+ return count;
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+}
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+
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+static ssize_t driver_override_show(struct device *dev,
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+ struct device_attribute *attr, char *buf)
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+{
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+ struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
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+
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+ return snprintf(buf, PAGE_SIZE, "%s\n", mc_dev->driver_override);
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+}
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+static DEVICE_ATTR_RW(driver_override);
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+
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static struct attribute *fsl_mc_dev_attrs[] = {
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&dev_attr_modalias.attr,
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+ &dev_attr_driver_override.attr,
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NULL,
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};
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@@ -749,6 +799,9 @@ EXPORT_SYMBOL_GPL(fsl_mc_device_add);
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*/
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void fsl_mc_device_remove(struct fsl_mc_device *mc_dev)
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{
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+ kfree(mc_dev->driver_override);
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+ mc_dev->driver_override = NULL;
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+
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/*
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* The device-specific remove callback will get invoked by device_del()
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*/
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