crypto/nx: Get NX capabilities for GZIP coprocessor type

phyp provides NX capabilities which gives recommended minimum
compression / decompression length and maximum request buffer size
in bytes.

Changes to get NX overall capabilities which points to the specific
features phyp supports. Then retrieve NXGZIP specific capabilities.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>

drivers/crypto/nx/nx-common-pseries.c

@@ -9,6 +9,7 @@
  */
 
 #include <asm/vio.h>
+#include <asm/hvcall.h>
 #include <asm/vas.h>
 
 #include "nx-842.h"
@@ -20,6 +21,24 @@ MODULE_DESCRIPTION("842 H/W Compression driver for IBM Power processors");
 MODULE_ALIAS_CRYPTO("842");
 MODULE_ALIAS_CRYPTO("842-nx");
 
+struct nx_ct_capabs_be {
+	__be64	descriptor;
+	__be64	req_max_processed_len;	/* Max bytes in one GZIP request */
+	__be64	min_compress_len;	/* Min compression size in bytes */
+	__be64	min_decompress_len;	/* Min decompression size in bytes */
+} __packed __aligned(0x1000);
+
+struct nx_ct_capabs {
+	char	name[VAS_DESCR_LEN + 1];
+	u64	descriptor;
+	u64	req_max_processed_len;	/* Max bytes in one GZIP request */
+	u64	min_compress_len;	/* Min compression in bytes */
+	u64	min_decompress_len;	/* Min decompression in bytes */
+};
+
+u64 capab_feat = 0;
+struct nx_ct_capabs nx_ct_capab;
+
 static struct nx842_constraints nx842_pseries_constraints = {
 	.alignment =	DDE_BUFFER_ALIGN,
 	.multiple =	DDE_BUFFER_LAST_MULT,
@@ -1066,6 +1085,66 @@ static void nx842_remove(struct vio_dev *viodev)
 	kfree(old_devdata);
 }
 
+/*
+ * Get NX capabilities from pHyp.
+ * Only NXGZIP capabilities are available right now and these values
+ * are available through sysfs.
+ */
+static void __init nxct_get_capabilities(void)
+{
+	struct vas_all_capabs_be *capabs_be;
+	struct nx_ct_capabs_be *nxc_be;
+	int rc;
+
+	capabs_be = kmalloc(sizeof(*capabs_be), GFP_KERNEL);
+	if (!capabs_be)
+		return;
+	/*
+	 * Get NX overall capabilities with feature type=0
+	 */
+	rc = plpar_vas_query_capabilities(H_QUERY_NX_CAPABILITIES, 0,
+					  (u64)virt_to_phys(capabs_be));
+	if (rc)
+		goto out;
+
+	capab_feat = be64_to_cpu(capabs_be->feat_type);
+	/*
+	 * NX-GZIP feature available
+	 */
+	if (capab_feat & VAS_NX_GZIP_FEAT_BIT) {
+		nxc_be = kmalloc(sizeof(*nxc_be), GFP_KERNEL);
+		if (!nxc_be)
+			goto out;
+		/*
+		 * Get capabilities for NX-GZIP feature
+		 */
+		rc = plpar_vas_query_capabilities(H_QUERY_NX_CAPABILITIES,
+						  VAS_NX_GZIP_FEAT,
+						  (u64)virt_to_phys(nxc_be));
+	} else {
+		pr_err("NX-GZIP feature is not available\n");
+		rc = -EINVAL;
+	}
+
+	if (!rc) {
+		snprintf(nx_ct_capab.name, VAS_DESCR_LEN + 1, "%.8s",
+			 (char *)&nxc_be->descriptor);
+		nx_ct_capab.descriptor = be64_to_cpu(nxc_be->descriptor);
+		nx_ct_capab.req_max_processed_len =
+				be64_to_cpu(nxc_be->req_max_processed_len);
+		nx_ct_capab.min_compress_len =
+				be64_to_cpu(nxc_be->min_compress_len);
+		nx_ct_capab.min_decompress_len =
+				be64_to_cpu(nxc_be->min_decompress_len);
+	} else {
+		capab_feat = 0;
+	}
+
+	kfree(nxc_be);
+out:
+	kfree(capabs_be);
+}
+
 static const struct vio_device_id nx842_vio_driver_ids[] = {
 	{"ibm,compression-v1", "ibm,compression"},
 	{"", ""},
@@ -1093,6 +1172,10 @@ static int __init nx842_pseries_init(void)
 		return -ENOMEM;
 
 	RCU_INIT_POINTER(devdata, new_devdata);
+	/*
+	 * Get NX capabilities from pHyp which is used for NX-GZIP.
+	 */
+	nxct_get_capabilities();
 
 	ret = vio_register_driver(&nx842_vio_driver);
 	if (ret) {