dmaengine: ste_dma40: support fixed physical channel allocation

This patch makes existing use_fixed_channel field (of stedma40_chan_cfg
structure) applicable to physical channels.
Signed-off-by: Gerald Baeza <gerald.baeza@stericsson.com>
Tested-by: Yannick Fertre <yannick.fertre@stericsson.com>
Reviewed-by: Per Forlin <per.forlin@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Fabio Baltieri <fabio.baltieri@linaro.org>

drivers/dma/ste_dma40.c

@@ -1711,10 +1711,12 @@ static int d40_allocate_channel(struct d40_chan *d40c, bool *first_phy_user)
 	int i;
 	int j;
 	int log_num;
+	int num_phy_chans;
 	bool is_src;
 	bool is_log = d40c->dma_cfg.mode == STEDMA40_MODE_LOGICAL;
 
 	phys = d40c->base->phy_res;
+	num_phy_chans = d40c->base->num_phy_chans;
 
 	if (d40c->dma_cfg.dir == STEDMA40_PERIPH_TO_MEM) {
 		dev_type = d40c->dma_cfg.src_dev_type;
@@ -1735,13 +1737,20 @@ static int d40_allocate_channel(struct d40_chan *d40c, bool *first_phy_user)
 	if (!is_log) {
 		if (d40c->dma_cfg.dir == STEDMA40_MEM_TO_MEM) {
 			/* Find physical half channel */
-			for (i = 0; i < d40c->base->num_phy_chans; i++) {
-
+			if (d40c->dma_cfg.use_fixed_channel) {
+				i = d40c->dma_cfg.phy_channel;
+				if (d40_alloc_mask_set(&phys[i], is_src,
+						       0, is_log,
+						       first_phy_user))
+					goto found_phy;
+			} else {
+				for (i = 0; i < num_phy_chans; i++) {
 					if (d40_alloc_mask_set(&phys[i], is_src,
 						       0, is_log,
 						       first_phy_user))
 						goto found_phy;
 				}
+			}
 		} else
 			for (j = 0; j < d40c->base->num_phy_chans; j += 8) {
 				int phy_num = j  + event_group * 2;