platform/x86/intel/ifs: Reorganize driver data

The struct holding device driver data contained both read only(ro)
and read write(rw) fields.

Separating ro fields from rw fields was recommended as
a preferable design pattern during review[1].

Group ro fields into a separate const struct. Associate it to
the miscdevice being registered by keeping its pointer in the
same container struct as the miscdevice.

Link: https://lore.kernel.org/lkml/Y+9H9otxLYPqMkUh@kroah.com/ [1]
Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/r/20230322003359.213046-3-jithu.joseph@intel.comReviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/intel/ifs/core.c

@@ -22,11 +22,13 @@ MODULE_DEVICE_TABLE(x86cpu, ifs_cpu_ids);
 
 bool *ifs_pkg_auth;
 
+static const struct ifs_test_caps scan_test = {
+	.integrity_cap_bit = MSR_INTEGRITY_CAPS_PERIODIC_BIST_BIT,
+	.test_num = 0,
+};
+
 static struct ifs_device ifs_device = {
-	.data = {
-		.integrity_cap_bit = MSR_INTEGRITY_CAPS_PERIODIC_BIST_BIT,
-		.test_num = 0,
-	},
+	.test_caps = &scan_test,
 	.misc = {
 		.name = "intel_ifs_0",
 		.nodename = "intel_ifs/0",
@@ -55,7 +57,7 @@ static int __init ifs_init(void)
 
 	ifs_device.misc.groups = ifs_get_groups();
 
-	if (!(msrval & BIT(ifs_device.data.integrity_cap_bit)))
+	if (!(msrval & BIT(ifs_device.test_caps->integrity_cap_bit)))
 		return -ENODEV;
 
 	ifs_pkg_auth = kmalloc_array(topology_max_packages(), sizeof(bool), GFP_KERNEL);

drivers/platform/x86/intel/ifs/ifs.h

@@ -197,9 +197,13 @@ union ifs_status {
 #define IFS_SW_TIMEOUT				0xFD
 #define IFS_SW_PARTIAL_COMPLETION		0xFE
 
+struct ifs_test_caps {
+	int	integrity_cap_bit;
+	int	test_num;
+};
+
 /**
  * struct ifs_data - attributes related to intel IFS driver
- * @integrity_cap_bit: MSR_INTEGRITY_CAPS bit enumerating this test
  * @loaded_version: stores the currently loaded ifs image version.
  * @loaded: If a valid test binary has been loaded into the memory
  * @loading_error: Error occurred on another CPU while loading image
@@ -207,10 +211,8 @@ union ifs_status {
  * @status: it holds simple status pass/fail/untested
  * @scan_details: opaque scan status code from h/w
  * @cur_batch: number indicating the currently loaded test file
- * @test_num: number indicating the test type
  */
 struct ifs_data {
-	int	integrity_cap_bit;
 	int	loaded_version;
 	bool	loaded;
 	bool	loading_error;
@@ -218,7 +220,6 @@ struct ifs_data {
 	int	status;
 	u64	scan_details;
 	u32	cur_batch;
-	int	test_num;
 };
 
 struct ifs_work {
@@ -227,7 +228,8 @@ struct ifs_work {
 };
 
 struct ifs_device {
-	struct ifs_data data;
+	const struct ifs_test_caps *test_caps;
+	struct ifs_data rw_data;
 	struct miscdevice misc;
 };
 
@@ -236,7 +238,15 @@ static inline struct ifs_data *ifs_get_data(struct device *dev)
 	struct miscdevice *m = dev_get_drvdata(dev);
 	struct ifs_device *d = container_of(m, struct ifs_device, misc);
 
-	return &d->data;
+	return &d->rw_data;
+}
+
+static inline const struct ifs_test_caps *ifs_get_test_caps(struct device *dev)
+{
+	struct miscdevice *m = dev_get_drvdata(dev);
+	struct ifs_device *d = container_of(m, struct ifs_device, misc);
+
+	return d->test_caps;
 }
 
 extern bool *ifs_pkg_auth;

drivers/platform/x86/intel/ifs/load.c

@@ -257,13 +257,14 @@ static int image_sanity_check(struct device *dev, const struct microcode_header_
  */
 int ifs_load_firmware(struct device *dev)
 {
+	const struct ifs_test_caps *test = ifs_get_test_caps(dev);
 	struct ifs_data *ifsd = ifs_get_data(dev);
 	const struct firmware *fw;
 	char scan_path[64];
 	int ret = -EINVAL;
 
 	snprintf(scan_path, sizeof(scan_path), "intel/ifs_%d/%02x-%02x-%02x-%02x.scan",
-		 ifsd->test_num, boot_cpu_data.x86, boot_cpu_data.x86_model,
+		 test->test_num, boot_cpu_data.x86, boot_cpu_data.x86_model,
 		 boot_cpu_data.x86_stepping, ifsd->cur_batch);
 
 	ret = request_firmware_direct(&fw, scan_path, dev);