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authorDaniel Axtens <dja@axtens.net>2015-08-14 17:41:25 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2015-08-14 21:32:07 +1000
commit13e68d8bd05c998cae452a4f3400af1e8edd852e (patch)
treed17ff97c9f46a663b5cb4916fc333703b2cdfea4
parent4e1efb403c1c016ae831bd9988a7d2e5e0af41a0 (diff)
cxl: Allow the kernel to trust that an image won't change on PERST.
Provide a kernel API and a sysfs entry which allow a user to specify that when a card is PERSTed, it's image will stay the same, allowing it to participate in EEH. cxl_reset is used to reflash the card. In that case, we cannot safely assert that the image will not change. Therefore, disallow cxl_reset if the flag is set. Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
-rw-r--r--Documentation/ABI/testing/sysfs-class-cxl10
-rw-r--r--drivers/misc/cxl/api.c7
-rw-r--r--drivers/misc/cxl/cxl.h1
-rw-r--r--drivers/misc/cxl/pci.c7
-rw-r--r--drivers/misc/cxl/sysfs.c26
-rw-r--r--include/misc/cxl.h10
6 files changed, 61 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-cxl b/Documentation/ABI/testing/sysfs-class-cxl
index acfe9df83139..b07e86d4597f 100644
--- a/Documentation/ABI/testing/sysfs-class-cxl
+++ b/Documentation/ABI/testing/sysfs-class-cxl
@@ -223,3 +223,13 @@ Description: write only
Writing 1 will issue a PERST to card which may cause the card
to reload the FPGA depending on load_image_on_perst.
Users: https://github.com/ibm-capi/libcxl
+
+What: /sys/class/cxl/<card>/perst_reloads_same_image
+Date: July 2015
+Contact: linuxppc-dev@lists.ozlabs.org
+Description: read/write
+ Trust that when an image is reloaded via PERST, it will not
+ have changed.
+ 0 = don't trust, the image may be different (default)
+ 1 = trust that the image will not change.
+Users: https://github.com/ibm-capi/libcxl
diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
index 729e0851167d..6a768a9ad22f 100644
--- a/drivers/misc/cxl/api.c
+++ b/drivers/misc/cxl/api.c
@@ -327,3 +327,10 @@ int cxl_afu_reset(struct cxl_context *ctx)
return cxl_afu_check_and_enable(afu);
}
EXPORT_SYMBOL_GPL(cxl_afu_reset);
+
+void cxl_perst_reloads_same_image(struct cxl_afu *afu,
+ bool perst_reloads_same_image)
+{
+ afu->adapter->perst_same_image = perst_reloads_same_image;
+}
+EXPORT_SYMBOL_GPL(cxl_perst_reloads_same_image);
diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
index d540542f9931..cda02412b01e 100644
--- a/drivers/misc/cxl/cxl.h
+++ b/drivers/misc/cxl/cxl.h
@@ -493,6 +493,7 @@ struct cxl {
bool user_image_loaded;
bool perst_loads_image;
bool perst_select_user;
+ bool perst_same_image;
};
int cxl_alloc_one_irq(struct cxl *adapter);
diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
index 2b61cb1ee62c..bfbd6478c0c5 100644
--- a/drivers/misc/cxl/pci.c
+++ b/drivers/misc/cxl/pci.c
@@ -878,6 +878,12 @@ int cxl_reset(struct cxl *adapter)
int i;
u32 val;
+ if (adapter->perst_same_image) {
+ dev_warn(&dev->dev,
+ "cxl: refusing to reset/reflash when perst_reloads_same_image is set.\n");
+ return -EINVAL;
+ }
+
dev_info(&dev->dev, "CXL reset\n");
/* pcie_warm_reset requests a fundamental pci reset which includes a
@@ -1151,6 +1157,7 @@ static struct cxl *cxl_init_adapter(struct pci_dev *dev)
* configure/reconfigure
*/
adapter->perst_loads_image = true;
+ adapter->perst_same_image = false;
rc = cxl_configure_adapter(adapter, dev);
if (rc) {
diff --git a/drivers/misc/cxl/sysfs.c b/drivers/misc/cxl/sysfs.c
index 31f38bc71a3d..6619cf1f6e1f 100644
--- a/drivers/misc/cxl/sysfs.c
+++ b/drivers/misc/cxl/sysfs.c
@@ -112,12 +112,38 @@ static ssize_t load_image_on_perst_store(struct device *device,
return count;
}
+static ssize_t perst_reloads_same_image_show(struct device *device,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cxl *adapter = to_cxl_adapter(device);
+
+ return scnprintf(buf, PAGE_SIZE, "%i\n", adapter->perst_same_image);
+}
+
+static ssize_t perst_reloads_same_image_store(struct device *device,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct cxl *adapter = to_cxl_adapter(device);
+ int rc;
+ int val;
+
+ rc = sscanf(buf, "%i", &val);
+ if ((rc != 1) || !(val == 1 || val == 0))
+ return -EINVAL;
+
+ adapter->perst_same_image = (val == 1 ? true : false);
+ return count;
+}
+
static struct device_attribute adapter_attrs[] = {
__ATTR_RO(caia_version),
__ATTR_RO(psl_revision),
__ATTR_RO(base_image),
__ATTR_RO(image_loaded),
__ATTR_RW(load_image_on_perst),
+ __ATTR_RW(perst_reloads_same_image),
__ATTR(reset, S_IWUSR, NULL, reset_adapter_store),
};
diff --git a/include/misc/cxl.h b/include/misc/cxl.h
index 7a6c1d6cc173..f2ffe5bd720d 100644
--- a/include/misc/cxl.h
+++ b/include/misc/cxl.h
@@ -200,4 +200,14 @@ unsigned int cxl_fd_poll(struct file *file, struct poll_table_struct *poll);
ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
loff_t *off);
+/*
+ * For EEH, a driver may want to assert a PERST will reload the same image
+ * from flash into the FPGA.
+ *
+ * This is a property of the entire adapter, not a single AFU, so drivers
+ * should set this property with care!
+ */
+void cxl_perst_reloads_same_image(struct cxl_afu *afu,
+ bool perst_reloads_same_image);
+
#endif /* _MISC_CXL_H */