[SCSI] libsas: Provide a transport-level facility to request SAS addrs

Provide a facility to use the request_firmware() interface to get a SAS
address from userspace.  This can be used by SAS LLDDs that cannot
obtain the address from the host adapter.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/libsas/sas_scsi_host.c

@@ -24,6 +24,8 @@
  */
 
 #include <linux/kthread.h>
+#include <linux/firmware.h>
+#include <linux/ctype.h>
 
 #include "sas_internal.h"
 
@@ -1064,6 +1066,45 @@ void sas_target_destroy(struct scsi_target *starget)
 	return;
 }
 
+static void sas_parse_addr(u8 *sas_addr, const char *p)
+{
+	int i;
+	for (i = 0; i < SAS_ADDR_SIZE; i++) {
+		u8 h, l;
+		if (!*p)
+			break;
+		h = isdigit(*p) ? *p-'0' : toupper(*p)-'A'+10;
+		p++;
+		l = isdigit(*p) ? *p-'0' : toupper(*p)-'A'+10;
+		p++;
+		sas_addr[i] = (h<<4) | l;
+	}
+}
+
+#define SAS_STRING_ADDR_SIZE	16
+
+int sas_request_addr(struct Scsi_Host *shost, u8 *addr)
+{
+	int res;
+	const struct firmware *fw;
+
+	res = request_firmware(&fw, "sas_addr", &shost->shost_gendev);
+	if (res)
+		return res;
+
+	if (fw->size < SAS_STRING_ADDR_SIZE) {
+		res = -ENODEV;
+		goto out;
+	}
+
+	sas_parse_addr(addr, fw->data);
+
+out:
+	release_firmware(fw);
+	return res;
+}
+EXPORT_SYMBOL_GPL(sas_request_addr);
+
 EXPORT_SYMBOL_GPL(sas_queuecommand);
 EXPORT_SYMBOL_GPL(sas_target_alloc);
 EXPORT_SYMBOL_GPL(sas_slave_configure);

include/scsi/libsas.h

@@ -677,4 +677,6 @@ extern void sas_ssp_task_response(struct device *dev, struct sas_task *task,
 				  struct ssp_response_iu *iu);
 struct sas_phy *sas_find_local_phy(struct domain_device *dev);
 
+int sas_request_addr(struct Scsi_Host *shost, u8 *addr);
+
 #endif /* _SASLIB_H_ */