DMAENGINE: ste_dma40: removed a few magic numbers

Make sure to extract the revision field explicitly and document
what bits are being accessed here without magic numbers.

Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

2 files changed, 15 insertions, 6 deletions

diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index a6a7d66df77a..c042103d7c0d 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -41,7 +41,7 @@
 #define D40_ALLOC_LOG_FREE      0
 
 /* Hardware designer of the block */
-#define D40_PERIPHID2_DESIGNER 0x8
+#define D40_HW_DESIGNER 0x8
 
 /**
  * enum 40_command - The different commands and/or statuses.
@@ -2438,6 +2438,7 @@ static struct d40_base * __init d40_hw_detect_init(struct platform_device *pdev)
         int num_phy_chans;
         int i;
         u32 val;
+        u32 rev;
 
         clk = clk_get(&pdev->dev, NULL);
 
@@ -2476,21 +2477,26 @@ static struct d40_base * __init d40_hw_detect_init(struct platform_device *pdev)
                 }
         }
 
-        /* Get silicon revision */
+        /* Get silicon revision and designer */
         val = readl(virtbase + D40_DREG_PERIPHID2);
 
-        if ((val & 0xf) != D40_PERIPHID2_DESIGNER) {
+        if ((val & D40_DREG_PERIPHID2_DESIGNER_MASK) !=
+            D40_HW_DESIGNER) {
                 dev_err(&pdev->dev,
                         "[%s] Unknown designer! Got %x wanted %x\n",
-                        __func__, val & 0xf, D40_PERIPHID2_DESIGNER);
+                        __func__, val & D40_DREG_PERIPHID2_DESIGNER_MASK,
+                        D40_HW_DESIGNER);
                 goto failure;
         }
 
+        rev = (val & D40_DREG_PERIPHID2_REV_MASK) >>
+                D40_DREG_PERIPHID2_REV_POS;
+
         /* The number of physical channels on this HW */
         num_phy_chans = 4 * (readl(virtbase + D40_DREG_ICFG) & 0x7) + 4;
 
         dev_info(&pdev->dev, "hardware revision: %d @ 0x%x\n",
-                 (val >> 4) & 0xf, res->start);
+                 rev, res->start);
 
         plat_data = pdev->dev.platform_data;
 
@@ -2512,7 +2518,7 @@ static struct d40_base * __init d40_hw_detect_init(struct platform_device *pdev)
                 goto failure;
         }
 
-        base->rev = (val >> 4) & 0xf;
+        base->rev = rev;
         base->clk = clk;
         base->num_phy_chans = num_phy_chans;
         base->num_log_chans = num_log_chans;
diff --git a/drivers/dma/ste_dma40_ll.h b/drivers/dma/ste_dma40_ll.h
index 0c468c310c18..7a6acecfccd5 100644
--- a/drivers/dma/ste_dma40_ll.h
+++ b/drivers/dma/ste_dma40_ll.h
@@ -163,6 +163,9 @@
 #define D40_DREG_PERIPHID0      0xFE0
 #define D40_DREG_PERIPHID1      0xFE4
 #define D40_DREG_PERIPHID2      0xFE8
+#define D40_DREG_PERIPHID2_REV_POS 4
+#define D40_DREG_PERIPHID2_REV_MASK (0xf << D40_DREG_PERIPHID2_REV_POS)
+#define D40_DREG_PERIPHID2_DESIGNER_MASK 0xf
 #define D40_DREG_PERIPHID3      0xFEC
 #define D40_DREG_CELLID0        0xFF0
 #define D40_DREG_CELLID1        0xFF4