[PATCH 2/9] platform/x86/intel/sdsi: Hide attributes if hardware doesn't support

David E. Box
2022-11-01T19:11:04Z

Provisioning capabilities are enabled by a bit set by BIOS. Read this bit
and hide the provisioning attributes if the On Demand feature is not
enabled.

Also, remove the sdsi_enabled boolean from private and instead add a
features register since this will be used for future features.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
---
drivers/platform/x86/intel/sdsi.c | 33 ++++++++++++++++++++-----------
1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/drivers/platform/x86/intel/sdsi.c b/drivers/platform/x86/intel/sdsi.c
index 32793919473d..bca05b4dd983 100644
--- a/drivers/platform/x86/intel/sdsi.c
+++ b/drivers/platform/x86/intel/sdsi.c
@@ -41,7 +41,8 @@
#define SDSI_SIZE_READ_MSG (SDSI_SIZE_MAILBOX * 4)

#define SDSI_ENABLED_FEATURES_OFFSET 16
-#define SDSI_ENABLED BIT(3)
+#define SDSI_FEATURE_SDSI BIT(3)
+
#define SDSI_SOCKET_ID_OFFSET 64
#define SDSI_SOCKET_ID GENMASK(3, 0)

@@ -100,7 +101,7 @@ struct sdsi_priv {
void __iomem *mbox_addr;
void __iomem *regs_addr;
u32 guid;
- bool sdsi_enabled;
+ u32 features;
};

/* SDSi mailbox operations must be performed using 64bit mov instructions */
@@ -332,9 +333,6 @@ static ssize_t sdsi_provision(struct sdsi_priv *priv, char *buf, size_t count,
struct sdsi_mbox_info info;
int ret;

- if (!priv->sdsi_enabled)
- return -EPERM;
-
if (count > (SDSI_SIZE_WRITE_MSG - SDSI_SIZE_CMD))
return -EOVERFLOW;

@@ -405,9 +403,6 @@ static long state_certificate_read(struct file *filp, struct kobject *kobj,
size_t size;
int ret;

- if (!priv->sdsi_enabled)
- return -EPERM;
-
if (off)
return 0;

@@ -464,6 +459,23 @@ static struct bin_attribute *sdsi_bin_attrs[] = {
NULL
};

+static umode_t
+sdsi_battr_is_visible(struct kobject *kobj, struct bin_attribute *attr, int n)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct sdsi_priv *priv = dev_get_drvdata(dev);
+
+ /* Registers file is always readable if the device is present */
+ if (attr == &bin_attr_registers)
+ return attr->attr.mode;
+
+ /* All other attributes not visible if BIOS has not enabled On Demand */
+ if (!(priv->features & SDSI_FEATURE_SDSI))
+ return 0;
+
+ return attr->attr.mode;
+}
+
static ssize_t guid_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct sdsi_priv *priv = dev_get_drvdata(dev);
@@ -480,6 +492,7 @@ static struct attribute *sdsi_attrs[] = {
static const struct attribute_group sdsi_group = {
.attrs = sdsi_attrs,
.bin_attrs = sdsi_bin_attrs,
+ .is_bin_visible = sdsi_battr_is_visible,
};
__ATTRIBUTE_GROUPS(sdsi);

@@ -490,7 +503,6 @@ static int sdsi_map_mbox_registers(struct sdsi_priv *priv, struct pci_dev *paren
u32 size = FIELD_GET(DT_SIZE, disc_table->access_info);
u32 tbir = FIELD_GET(DT_TBIR, disc_table->offset);
u32 offset = DT_OFFSET(disc_table->offset);
- u32 features_offset;
struct resource res = {};

/* Starting location of SDSi MMIO region based on access type */
@@ -528,8 +540,7 @@ static int sdsi_map_mbox_registers(struct sdsi_priv *priv, struct pci_dev *paren
priv->mbox_addr = priv->control_addr + SDSI_SIZE_CONTROL;
priv->regs_addr = priv->mbox_addr + SDSI_SIZE_MAILBOX;

- features_offset = readq(priv->regs_addr + SDSI_ENABLED_FEATURES_OFFSET);
- priv->sdsi_enabled = !!(features_offset & SDSI_ENABLED);
+ priv->features = readq(priv->regs_addr + SDSI_ENABLED_FEATURES_OFFSET);

return 0;
}
--
2.25.1