This patch adds support for global error reporting for FPGA
Management Engine (FME), it introduces sysfs interfaces to
report different error detected by the hardware, and allow
user to clear errors or inject error for testing purpose.
Signed-off-by: Luwei Kang <[email protected]>
Signed-off-by: Ananda Ravuri <[email protected]>
Signed-off-by: Xu Yilun <[email protected]>
Signed-off-by: Wu Hao <[email protected]>
---
v2: fix issues found in sysfs doc.
fix returned error code issues for writable sysfs interfaces.
(use -EINVAL if input doesn't match error code)
reorder the sysfs groups in code.
---
Documentation/ABI/testing/sysfs-platform-dfl-fme | 75 +++++
drivers/fpga/Makefile | 2 +-
drivers/fpga/dfl-fme-error.c | 385 +++++++++++++++++++++++
drivers/fpga/dfl-fme-main.c | 4 +
drivers/fpga/dfl-fme.h | 2 +
drivers/fpga/dfl.h | 2 +
6 files changed, 469 insertions(+), 1 deletion(-)
create mode 100644 drivers/fpga/dfl-fme-error.c
diff --git a/Documentation/ABI/testing/sysfs-platform-dfl-fme b/Documentation/ABI/testing/sysfs-platform-dfl-fme
index e2ba92d..503984b 100644
--- a/Documentation/ABI/testing/sysfs-platform-dfl-fme
+++ b/Documentation/ABI/testing/sysfs-platform-dfl-fme
@@ -175,3 +175,78 @@ Contact: Wu Hao <[email protected]>
Description: Read-only. Read this file to get current Latency Tolerance
Reporting (ltr) value. This ltr impacts the CPU low power
state in integrated solution.
+
+What: /sys/bus/platform/devices/dfl-fme.0/errors/revision
+Date: April 2019
+KernelVersion: 5.2
+Contact: Wu Hao <[email protected]>
+Description: Read-only. Read this file to get the revision of this global
+ error reporting private feature.
+
+What: /sys/bus/platform/devices/dfl-fme.0/errors/pcie0_errors
+Date: April 2019
+KernelVersion: 5.2
+Contact: Wu Hao <[email protected]>
+Description: Read-Write. Read this file for errors detected on pcie0 link.
+ Write this file to clear errors logged in pcie0_errors. Write
+ fails with -EINVAL if input parsing fails or input error code
+ doesn't match.
+
+What: /sys/bus/platform/devices/dfl-fme.0/errors/pcie1_errors
+Date: April 2019
+KernelVersion: 5.2
+Contact: Wu Hao <[email protected]>
+Description: Read-Write. Read this file for errors detected on pcie1 link.
+ Write this file to clear errors logged in pcie1_errors. Write
+ fails with -EINVAL if input parsing fails or input error code
+ doesn't match.
+
+What: /sys/bus/platform/devices/dfl-fme.0/errors/nonfatal_errors
+Date: April 2019
+KernelVersion: 5.2
+Contact: Wu Hao <[email protected]>
+Description: Read-only. It returns non-fatal errors detected.
+
+What: /sys/bus/platform/devices/dfl-fme.0/errors/catfatal_errors
+Date: April 2019
+KernelVersion: 5.2
+Contact: Wu Hao <[email protected]>
+Description: Read-only. It returns catastrophic and fatal errors detected.
+
+What: /sys/bus/platform/devices/dfl-fme.0/errors/inject_error
+Date: April 2019
+KernelVersion: 5.2
+Contact: Wu Hao <[email protected]>
+Description: Read-Write. Read this file to check errors injected. Write this
+ file to inject errors for testing purpose. Write fails with
+ -EINVAL if input parsing fails or input inject error code isn't
+ supported.
+
+What: /sys/bus/platform/devices/dfl-fme.0/errors/fme-errors/errors
+Date: April 2019
+KernelVersion: 5.2
+Contact: Wu Hao <[email protected]>
+Description: Read-only. Read this file to get errors detected by hardware.
+
+What: /sys/bus/platform/devices/dfl-fme.0/errors/fme-errors/first_error
+Date: April 2019
+KernelVersion: 5.2
+Contact: Wu Hao <[email protected]>
+Description: Read-only. Read this file to get the first error detected by
+ hardware.
+
+What: /sys/bus/platform/devices/dfl-fme.0/errors/fme-errors/next_error
+Date: April 2019
+KernelVersion: 5.2
+Contact: Wu Hao <[email protected]>
+Description: Read-only. Read this file to get the second error detected by
+ hardware.
+
+What: /sys/bus/platform/devices/dfl-fme.0/errors/fme-errors/clear
+Date: April 2019
+KernelVersion: 5.2
+Contact: Wu Hao <[email protected]>
+Description: Write-only. Write error code to this file to clear all errors
+ logged in errors, first_error and next_error. Write fails with
+ -EINVAL if input parsing fails or input error code doesn't
+ match.
diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
index f1f0af7..1a9fa3d 100644
--- a/drivers/fpga/Makefile
+++ b/drivers/fpga/Makefile
@@ -38,7 +38,7 @@ obj-$(CONFIG_FPGA_DFL_FME_BRIDGE) += dfl-fme-br.o
obj-$(CONFIG_FPGA_DFL_FME_REGION) += dfl-fme-region.o
obj-$(CONFIG_FPGA_DFL_AFU) += dfl-afu.o
-dfl-fme-objs := dfl-fme-main.o dfl-fme-pr.o
+dfl-fme-objs := dfl-fme-main.o dfl-fme-pr.o dfl-fme-error.o
dfl-afu-objs := dfl-afu-main.o dfl-afu-region.o dfl-afu-dma-region.o
dfl-afu-objs += dfl-afu-error.o
diff --git a/drivers/fpga/dfl-fme-error.c b/drivers/fpga/dfl-fme-error.c
new file mode 100644
index 0000000..772b53e
--- /dev/null
+++ b/drivers/fpga/dfl-fme-error.c
@@ -0,0 +1,385 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for FPGA Management Engine Error Management
+ *
+ * Copyright 2019 Intel Corporation, Inc.
+ *
+ * Authors:
+ * Kang Luwei <[email protected]>
+ * Xiao Guangrong <[email protected]>
+ * Wu Hao <[email protected]>
+ * Joseph Grecco <[email protected]>
+ * Enno Luebbers <[email protected]>
+ * Tim Whisonant <[email protected]>
+ * Ananda Ravuri <[email protected]>
+ * Mitchel, Henry <[email protected]>
+ */
+
+#include <linux/uaccess.h>
+
+#include "dfl.h"
+#include "dfl-fme.h"
+
+#define FME_ERROR_MASK 0x8
+#define FME_ERROR 0x10
+#define MBP_ERROR BIT_ULL(6)
+#define PCIE0_ERROR_MASK 0x18
+#define PCIE0_ERROR 0x20
+#define PCIE1_ERROR_MASK 0x28
+#define PCIE1_ERROR 0x30
+#define FME_FIRST_ERROR 0x38
+#define FME_NEXT_ERROR 0x40
+#define RAS_NONFAT_ERROR_MASK 0x48
+#define RAS_NONFAT_ERROR 0x50
+#define RAS_CATFAT_ERROR_MASK 0x58
+#define RAS_CATFAT_ERROR 0x60
+#define RAS_ERROR_INJECT 0x68
+#define INJECT_ERROR_MASK GENMASK_ULL(2, 0)
+
+static ssize_t revision_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct device *err_dev = dev->parent;
+ void __iomem *base;
+
+ base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
+
+ return scnprintf(buf, PAGE_SIZE, "%u\n", dfl_feature_revision(base));
+}
+static DEVICE_ATTR_RO(revision);
+
+static ssize_t pcie0_errors_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct device *err_dev = dev->parent;
+ void __iomem *base;
+
+ base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
+
+ return scnprintf(buf, PAGE_SIZE, "0x%llx\n",
+ (unsigned long long)readq(base + PCIE0_ERROR));
+}
+
+static ssize_t pcie0_errors_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct dfl_feature_platform_data *pdata = dev_get_platdata(dev->parent);
+ struct device *err_dev = dev->parent;
+ void __iomem *base;
+ int ret = 0;
+ u64 v, val;
+
+ if (kstrtou64(buf, 0, &val))
+ return -EINVAL;
+
+ base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
+
+ mutex_lock(&pdata->lock);
+ writeq(GENMASK_ULL(63, 0), base + PCIE0_ERROR_MASK);
+
+ v = readq(base + PCIE0_ERROR);
+ if (val == v)
+ writeq(v, base + PCIE0_ERROR);
+ else
+ ret = -EINVAL;
+
+ writeq(0ULL, base + PCIE0_ERROR_MASK);
+ mutex_unlock(&pdata->lock);
+ return ret ? ret : count;
+}
+static DEVICE_ATTR_RW(pcie0_errors);
+
+static ssize_t pcie1_errors_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct device *err_dev = dev->parent;
+ void __iomem *base;
+
+ base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
+
+ return scnprintf(buf, PAGE_SIZE, "0x%llx\n",
+ (unsigned long long)readq(base + PCIE1_ERROR));
+}
+
+static ssize_t pcie1_errors_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct dfl_feature_platform_data *pdata = dev_get_platdata(dev->parent);
+ struct device *err_dev = dev->parent;
+ void __iomem *base;
+ int ret = 0;
+ u64 v, val;
+
+ if (kstrtou64(buf, 0, &val))
+ return -EINVAL;
+
+ base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
+
+ mutex_lock(&pdata->lock);
+ writeq(GENMASK_ULL(63, 0), base + PCIE1_ERROR_MASK);
+
+ v = readq(base + PCIE1_ERROR);
+ if (val == v)
+ writeq(v, base + PCIE1_ERROR);
+ else
+ ret = -EINVAL;
+
+ writeq(0ULL, base + PCIE1_ERROR_MASK);
+ mutex_unlock(&pdata->lock);
+ return ret ? ret : count;
+}
+static DEVICE_ATTR_RW(pcie1_errors);
+
+static ssize_t nonfatal_errors_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct device *err_dev = dev->parent;
+ void __iomem *base;
+
+ base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
+
+ return scnprintf(buf, PAGE_SIZE, "0x%llx\n",
+ (unsigned long long)readq(base + RAS_NONFAT_ERROR));
+}
+static DEVICE_ATTR_RO(nonfatal_errors);
+
+static ssize_t catfatal_errors_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct device *err_dev = dev->parent;
+ void __iomem *base;
+
+ base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
+
+ return scnprintf(buf, PAGE_SIZE, "0x%llx\n",
+ (unsigned long long)readq(base + RAS_CATFAT_ERROR));
+}
+static DEVICE_ATTR_RO(catfatal_errors);
+
+static ssize_t inject_error_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct device *err_dev = dev->parent;
+ void __iomem *base;
+ u64 v;
+
+ base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
+
+ v = readq(base + RAS_ERROR_INJECT);
+
+ return scnprintf(buf, PAGE_SIZE, "0x%llx\n",
+ (unsigned long long)FIELD_GET(INJECT_ERROR_MASK, v));
+}
+
+static ssize_t inject_error_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct dfl_feature_platform_data *pdata = dev_get_platdata(dev->parent);
+ struct device *err_dev = dev->parent;
+ void __iomem *base;
+ u8 inject_error;
+ u64 v;
+
+ if (kstrtou8(buf, 0, &inject_error))
+ return -EINVAL;
+
+ if (inject_error & ~INJECT_ERROR_MASK)
+ return -EINVAL;
+
+ base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
+
+ mutex_lock(&pdata->lock);
+ v = readq(base + RAS_ERROR_INJECT);
+ v &= ~INJECT_ERROR_MASK;
+ v |= FIELD_PREP(INJECT_ERROR_MASK, inject_error);
+ writeq(v, base + RAS_ERROR_INJECT);
+ mutex_unlock(&pdata->lock);
+
+ return count;
+}
+static DEVICE_ATTR_RW(inject_error);
+
+static struct attribute *errors_attrs[] = {
+ &dev_attr_revision.attr,
+ &dev_attr_pcie0_errors.attr,
+ &dev_attr_pcie1_errors.attr,
+ &dev_attr_nonfatal_errors.attr,
+ &dev_attr_catfatal_errors.attr,
+ &dev_attr_inject_error.attr,
+ NULL,
+};
+
+static struct attribute_group errors_attr_group = {
+ .attrs = errors_attrs,
+};
+
+static ssize_t errors_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct device *err_dev = dev->parent;
+ void __iomem *base;
+
+ base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
+
+ return scnprintf(buf, PAGE_SIZE, "0x%llx\n",
+ (unsigned long long)readq(base + FME_ERROR));
+}
+static DEVICE_ATTR_RO(errors);
+
+static ssize_t first_error_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct device *err_dev = dev->parent;
+ void __iomem *base;
+
+ base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
+
+ return scnprintf(buf, PAGE_SIZE, "0x%llx\n",
+ (unsigned long long)readq(base + FME_FIRST_ERROR));
+}
+static DEVICE_ATTR_RO(first_error);
+
+static ssize_t next_error_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct device *err_dev = dev->parent;
+ void __iomem *base;
+
+ base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
+
+ return scnprintf(buf, PAGE_SIZE, "0x%llx\n",
+ (unsigned long long)readq(base + FME_NEXT_ERROR));
+}
+static DEVICE_ATTR_RO(next_error);
+
+static ssize_t clear_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct dfl_feature_platform_data *pdata = dev_get_platdata(dev->parent);
+ struct device *err_dev = dev->parent;
+ void __iomem *base;
+ u64 v, val;
+ int ret = 0;
+
+ if (kstrtou64(buf, 0, &val))
+ return -EINVAL;
+
+ base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
+
+ mutex_lock(&pdata->lock);
+ writeq(GENMASK_ULL(63, 0), base + FME_ERROR_MASK);
+
+ v = readq(base + FME_ERROR);
+ if (val == v) {
+ writeq(v, base + FME_ERROR);
+ v = readq(base + FME_FIRST_ERROR);
+ writeq(v, base + FME_FIRST_ERROR);
+ v = readq(base + FME_NEXT_ERROR);
+ writeq(v, base + FME_NEXT_ERROR);
+ } else {
+ ret = -EINVAL;
+ }
+
+ /* Workaround: disable MBP_ERROR if feature revision is 0 */
+ writeq(dfl_feature_revision(base) ? 0ULL : MBP_ERROR,
+ base + FME_ERROR_MASK);
+ mutex_unlock(&pdata->lock);
+ return ret ? ret : count;
+}
+static DEVICE_ATTR_WO(clear);
+
+static struct attribute *fme_errors_attrs[] = {
+ &dev_attr_errors.attr,
+ &dev_attr_first_error.attr,
+ &dev_attr_next_error.attr,
+ &dev_attr_clear.attr,
+ NULL,
+};
+
+static struct attribute_group fme_errors_attr_group = {
+ .attrs = fme_errors_attrs,
+ .name = "fme-errors",
+};
+
+static const struct attribute_group *error_groups[] = {
+ &fme_errors_attr_group,
+ &errors_attr_group,
+ NULL
+};
+
+static void fme_error_enable(struct dfl_feature *feature)
+{
+ void __iomem *base = feature->ioaddr;
+
+ /* Workaround: disable MBP_ERROR if revision is 0 */
+ writeq(dfl_feature_revision(feature->ioaddr) ? 0ULL : MBP_ERROR,
+ base + FME_ERROR_MASK);
+ writeq(0ULL, base + PCIE0_ERROR_MASK);
+ writeq(0ULL, base + PCIE1_ERROR_MASK);
+ writeq(0ULL, base + RAS_NONFAT_ERROR_MASK);
+ writeq(0ULL, base + RAS_CATFAT_ERROR_MASK);
+}
+
+static void err_dev_release(struct device *dev)
+{
+ kfree(dev);
+}
+
+static int fme_global_err_init(struct platform_device *pdev,
+ struct dfl_feature *feature)
+{
+ struct device *dev;
+ int ret = 0;
+
+ dev_dbg(&pdev->dev, "FME Global Error Reporting Init.\n");
+
+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ if (!dev)
+ return -ENOMEM;
+
+ dev->parent = &pdev->dev;
+ dev->release = err_dev_release;
+ dev_set_name(dev, "errors");
+
+ fme_error_enable(feature);
+
+ ret = device_register(dev);
+ if (ret) {
+ put_device(dev);
+ return ret;
+ }
+
+ ret = sysfs_create_groups(&dev->kobj, error_groups);
+ if (ret) {
+ device_unregister(dev);
+ return ret;
+ }
+
+ feature->priv = dev;
+
+ return ret;
+}
+
+static void fme_global_err_uinit(struct platform_device *pdev,
+ struct dfl_feature *feature)
+{
+ struct device *dev = feature->priv;
+
+ dev_dbg(&pdev->dev, "FME Global Error Reporting UInit.\n");
+
+ sysfs_remove_groups(&dev->kobj, error_groups);
+ device_unregister(dev);
+}
+
+const struct dfl_feature_id fme_global_err_id_table[] = {
+ {.id = FME_FEATURE_ID_GLOBAL_ERR,},
+ {0,}
+};
+
+const struct dfl_feature_ops fme_global_err_ops = {
+ .init = fme_global_err_init,
+ .uinit = fme_global_err_uinit,
+};
diff --git a/drivers/fpga/dfl-fme-main.c b/drivers/fpga/dfl-fme-main.c
index 7005316..1986b32 100644
--- a/drivers/fpga/dfl-fme-main.c
+++ b/drivers/fpga/dfl-fme-main.c
@@ -686,6 +686,10 @@ static void fme_power_mgmt_uinit(struct platform_device *pdev,
.ops = &fme_power_mgmt_ops,
},
{
+ .id_table = fme_global_err_id_table,
+ .ops = &fme_global_err_ops,
+ },
+ {
.ops = NULL,
},
};
diff --git a/drivers/fpga/dfl-fme.h b/drivers/fpga/dfl-fme.h
index 7a021c4..5fbe3f5 100644
--- a/drivers/fpga/dfl-fme.h
+++ b/drivers/fpga/dfl-fme.h
@@ -37,5 +37,7 @@ struct dfl_fme {
extern const struct dfl_feature_ops fme_pr_mgmt_ops;
extern const struct dfl_feature_id fme_pr_mgmt_id_table[];
+extern const struct dfl_feature_ops fme_global_err_ops;
+extern const struct dfl_feature_id fme_global_err_id_table[];
#endif /* __DFL_FME_H */
diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
index fbc57f0..6c32080 100644
--- a/drivers/fpga/dfl.h
+++ b/drivers/fpga/dfl.h
@@ -197,12 +197,14 @@ struct dfl_feature_driver {
* feature dev (platform device)'s reources.
* @ioaddr: mapped mmio resource address.
* @ops: ops of this sub feature.
+ * @priv: priv data of this feature.
*/
struct dfl_feature {
u64 id;
int resource_index;
void __iomem *ioaddr;
const struct dfl_feature_ops *ops;
+ void *priv;
};
#define DEV_STATUS_IN_USE 0
--
1.8.3.1
On Mon, Apr 29, 2019 at 4:13 AM Wu Hao <[email protected]> wrote:
Hi Hao,
The changes look good. There's one easy to fix thing that Greg has
pointed out recently on another patch (below).
>
> This patch adds support for global error reporting for FPGA
> Management Engine (FME), it introduces sysfs interfaces to
> report different error detected by the hardware, and allow
> user to clear errors or inject error for testing purpose.
>
> Signed-off-by: Luwei Kang <[email protected]>
> Signed-off-by: Ananda Ravuri <[email protected]>
> Signed-off-by: Xu Yilun <[email protected]>
> Signed-off-by: Wu Hao <[email protected]>
Acked-by: Alan Tull <[email protected]>
> ---
> v2: fix issues found in sysfs doc.
> fix returned error code issues for writable sysfs interfaces.
> (use -EINVAL if input doesn't match error code)
> reorder the sysfs groups in code.
> +static ssize_t revision_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + struct device *err_dev = dev->parent;
> + void __iomem *base;
> +
> + base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
> +
> + return scnprintf(buf, PAGE_SIZE, "%u\n", dfl_feature_revision(base));
Greg is discouraging use of scnprintf for sysfs attributes where it's
not needed [1].
Please fix this up the attributes added in this patchset. Besides
that, looks good, I added my Ack.
Alan
> +}
> +static DEVICE_ATTR_RO(revision);
[1] https://lkml.org/lkml/2019/4/25/1050
On Thu, May 09, 2019 at 11:27:36AM -0500, Alan Tull wrote:
> On Mon, Apr 29, 2019 at 4:13 AM Wu Hao <[email protected]> wrote:
>
> Hi Hao,
>
> The changes look good. There's one easy to fix thing that Greg has
> pointed out recently on another patch (below).
>
> >
> > This patch adds support for global error reporting for FPGA
> > Management Engine (FME), it introduces sysfs interfaces to
> > report different error detected by the hardware, and allow
> > user to clear errors or inject error for testing purpose.
> >
> > Signed-off-by: Luwei Kang <[email protected]>
> > Signed-off-by: Ananda Ravuri <[email protected]>
> > Signed-off-by: Xu Yilun <[email protected]>
> > Signed-off-by: Wu Hao <[email protected]>
>
> Acked-by: Alan Tull <[email protected]>
>
> > ---
> > v2: fix issues found in sysfs doc.
> > fix returned error code issues for writable sysfs interfaces.
> > (use -EINVAL if input doesn't match error code)
> > reorder the sysfs groups in code.
>
> > +static ssize_t revision_show(struct device *dev, struct device_attribute *attr,
> > + char *buf)
> > +{
> > + struct device *err_dev = dev->parent;
> > + void __iomem *base;
> > +
> > + base = dfl_get_feature_ioaddr_by_id(err_dev, FME_FEATURE_ID_GLOBAL_ERR);
> > +
> > + return scnprintf(buf, PAGE_SIZE, "%u\n", dfl_feature_revision(base));
>
> Greg is discouraging use of scnprintf for sysfs attributes where it's
> not needed [1].
>
> Please fix this up the attributes added in this patchset. Besides
> that, looks good, I added my Ack.
Sure, will fix them in the next patchset.
thanks a lot!
Hao
>
> Alan
>
> > +}
> > +static DEVICE_ATTR_RO(revision);
>
> [1] https://lkml.org/lkml/2019/4/25/1050