crypto: caam - Add API's to allocate/free Job Rings

With each of the Job Ring available as a platform device, the
Job Ring driver needs to take care of allocation/deallocation
of the Job Rings to the above interface layers. Added APIs
in Job Ring Driver to allocate/free Job rings

Signed-off-by: Ruchika Gupta <[e-mail]>
Reviewed-by: Garg Vakul-B16394 <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/crypto/caam/intern.h

···
 	struct tasklet_struct irqtask;
 	int irq;			/* One per queue */
 
+	/* Number of scatterlist crypt transforms active on the JobR */
+	atomic_t tfm_count ____cacheline_aligned;
+
 	/* Job ring info */
 	int ringsize;	/* Size of rings (assume input = output) */
 	struct caam_jrentry_info *entinfo;	/* Alloc'ed 1 per ring entry */

drivers/crypto/caam/jr.c

···
 	jrpriv = dev_get_drvdata(jrdev);
 
 	/*
-	 * Make sure ring is empty before release
+	 * Return EBUSY if job ring already allocated.
 	 */
-	if (rd_reg32(&jrpriv->rregs->outring_used) ||
-	    (rd_reg32(&jrpriv->rregs->inpring_avail) != JOBR_DEPTH)) {
+	if (atomic_read(&jrpriv->tfm_count)) {
 		dev_err(jrdev, "Device is busy\n");
 		return -EBUSY;
 	}
···
 	/* reenable / unmask IRQs */
 	clrbits32(&jrp->rregs->rconfig_lo, JRCFG_IMSK);
 }
+
+/**
+ * caam_jr_alloc() - Alloc a job ring for someone to use as needed.
+ *
+ * returns :  pointer to the newly allocated physical
+ *	      JobR dev can be written to if successful.
+ **/
+struct device *caam_jr_alloc(void)
+{
+	struct caam_drv_private_jr *jrpriv, *min_jrpriv = NULL;
+	struct device *dev = NULL;
+	int min_tfm_cnt	= INT_MAX;
+	int tfm_cnt;
+
+	spin_lock(&driver_data.jr_alloc_lock);
+
+	if (list_empty(&driver_data.jr_list)) {
+		spin_unlock(&driver_data.jr_alloc_lock);
+		return ERR_PTR(-ENODEV);
+	}
+
+	list_for_each_entry(jrpriv, &driver_data.jr_list, list_node) {
+		tfm_cnt = atomic_read(&jrpriv->tfm_count);
+		if (tfm_cnt < min_tfm_cnt) {
+			min_tfm_cnt = tfm_cnt;
+			min_jrpriv = jrpriv;
+		}
+		if (!min_tfm_cnt)
+			break;
+	}
+
+	if (min_jrpriv) {
+		atomic_inc(&min_jrpriv->tfm_count);
+		dev = min_jrpriv->dev;
+	}
+	spin_unlock(&driver_data.jr_alloc_lock);
+
+	return dev;
+}
+EXPORT_SYMBOL(caam_jr_alloc);
+
+/**
+ * caam_jr_free() - Free the Job Ring
+ * @rdev     - points to the dev that identifies the Job ring to
+ *             be released.
+ **/
+void caam_jr_free(struct device *rdev)
+{
+	struct caam_drv_private_jr *jrpriv = dev_get_drvdata(rdev);
+
+	atomic_dec(&jrpriv->tfm_count);
+}
+EXPORT_SYMBOL(caam_jr_free);
 
 /**
  * caam_jr_enqueue() - Enqueue a job descriptor head. Returns 0 if OK,
···
 	spin_lock(&driver_data.jr_alloc_lock);
 	list_add_tail(&jrpriv->list_node, &driver_data.jr_list);
 	spin_unlock(&driver_data.jr_alloc_lock);
+
+	atomic_set(&jrpriv->tfm_count, 0);
 
 	return 0;
 }

drivers/crypto/caam/jr.h

···
 #define JR_H
 
 /* Prototypes for backend-level services exposed to APIs */
+struct device *caam_jr_alloc(void);
+void caam_jr_free(struct device *rdev);
 int caam_jr_enqueue(struct device *dev, u32 *desc,
 		    void (*cbk)(struct device *dev, u32 *desc, u32 status,
 				void *areq),