[PATCH v4 15/16] crypto/nx: Get NX capabilities for GZIP coprocessor type

[Haren Myneni <haren@linux.ibm.com>]

The hypervisor provides different capabilities that it supports
to define the user space NX request. These capabilities are
recommended minimum compression / decompression lengths and the
maximum request buffer size in bytes.

Changes to get NX overall capabilities which points to the
specific features that the hypervisor supports. Then retrieve
the capabilities for the specific feature (available only
for NXGZIP).

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
---
 drivers/crypto/nx/nx-common-pseries.c | 89 +++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)

diff --git a/drivers/crypto/nx/nx-common-pseries.c b/drivers/crypto/nx/nx-common-pseries.c
index 9a40fca8a9e6..4a7278464156 100644
--- a/drivers/crypto/nx/nx-common-pseries.c
+++ b/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 +21,30 @@ MODULE_DESCRIPTION("842 H/W Compression driver for IBM Power processors");
 MODULE_ALIAS_CRYPTO("842");
 MODULE_ALIAS_CRYPTO("842-nx");
 
+/*
+ * Coprocessor type specific capabilities from the hypervisor.
+ */
+struct hv_nx_ct_caps {
+	__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);
+
+/*
+ * Coprocessor type specific capabilities.
+ */
+struct nx_ct_caps {
+	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 */
+};
+
+static u64 caps_feat;
+static struct nx_ct_caps nx_ct_caps;
+
 static struct nx842_constraints nx842_pseries_constraints = {
 	.alignment =	DDE_BUFFER_ALIGN,
 	.multiple =	DDE_BUFFER_LAST_MULT,
@@ -1066,6 +1091,66 @@ static void nx842_remove(struct vio_dev *viodev)
 	kfree(old_devdata);
 }
 
+/*
+ * Get NX capabilities from the hypervisor.
+ * Only NXGZIP capabilities are provided by the hypersvisor right
+ * now and these values are available to user space with sysfs.
+ */
+static void __init nxct_get_capabilities(void)
+{
+	struct hv_vas_all_caps *hv_caps;
+	struct hv_nx_ct_caps *hv_nxc;
+	int rc;
+
+	hv_caps = kmalloc(sizeof(*hv_caps), GFP_KERNEL);
+	if (!hv_caps)
+		return;
+	/*
+	 * Get NX overall capabilities with feature type=0
+	 */
+	rc = plpar_vas_query_capabilities(H_QUERY_NX_CAPABILITIES, 0,
+					  (u64)virt_to_phys(hv_caps));
+	if (rc)
+		goto out;
+
+	caps_feat = be64_to_cpu(hv_caps->feat_type);
+	/*
+	 * NX-GZIP feature available
+	 */
+	if (caps_feat & VAS_NX_GZIP_FEAT_BIT) {
+		hv_nxc = kmalloc(sizeof(*hv_nxc), GFP_KERNEL);
+		if (!hv_nxc)
+			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(hv_nxc));
+	} else {
+		pr_err("NX-GZIP feature is not available\n");
+		rc = -EINVAL;
+	}
+
+	if (!rc) {
+		snprintf(nx_ct_caps.name, VAS_DESCR_LEN + 1, "%.8s",
+			 (char *)&hv_nxc->descriptor);
+		nx_ct_caps.descriptor = be64_to_cpu(hv_nxc->descriptor);
+		nx_ct_caps.req_max_processed_len =
+				be64_to_cpu(hv_nxc->req_max_processed_len);
+		nx_ct_caps.min_compress_len =
+				be64_to_cpu(hv_nxc->min_compress_len);
+		nx_ct_caps.min_decompress_len =
+				be64_to_cpu(hv_nxc->min_decompress_len);
+	} else {
+		caps_feat = 0;
+	}
+
+	kfree(hv_nxc);
+out:
+	kfree(hv_caps);
+}
+
 static const struct vio_device_id nx842_vio_driver_ids[] = {
 	{"ibm,compression-v1", "ibm,compression"},
 	{"", ""},
@@ -1093,6 +1178,10 @@ static int __init nx842_pseries_init(void)
 		return -ENOMEM;
 
 	RCU_INIT_POINTER(devdata, new_devdata);
+	/*
+	 * Get NX capabilities from the hypervisor.
+	 */
+	nxct_get_capabilities();
 
 	ret = vio_register_driver(&nx842_vio_driver);
 	if (ret) {
-- 
2.18.2