[Qemu-devel] [PATCH 1/6] hw/sd.c: convert wp_groups in SDState to bitfield

[Igor Mitsyanko]

Representing each group write protection flag with only one bit instead of int
variable significantly reduces memory consumption.

Signed-off-by: Igor Mitsyanko <i.mitsya...@samsung.com>
---
 hw/sd.c |   36 ++++++++++++++++++++++--------------
 1 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/hw/sd.c b/hw/sd.c
index 07eb263..23e5f2f 100644
--- a/hw/sd.c
+++ b/hw/sd.c
@@ -81,7 +81,7 @@ struct SDState {
     uint8_t sd_status[64];
     uint32_t vhs;
     int wp_switch;
-    int *wp_groups;
+    uint8_t *wp_groups;
     uint64_t size;
     int blk_len;
     uint32_t erase_start;
@@ -415,7 +415,7 @@ static void sd_reset(SDState *sd, BlockDriverState *bdrv)
     if (sd->wp_groups)
         g_free(sd->wp_groups);
     sd->wp_switch = bdrv ? bdrv_is_read_only(bdrv) : 0;
-    sd->wp_groups = (int *) g_malloc0(sizeof(int) * sect);
+    sd->wp_groups = (uint8_t *)g_malloc0((sect >> 3) + 1);
     memset(sd->function_group, 0, sizeof(int) * 6);
     sd->erase_start = 0;
     sd->erase_end = 0;
@@ -484,9 +484,11 @@ static void sd_erase(SDState *sd)
     sd->erase_end = 0;
     sd->csd[14] |= 0x40;
 
-    for (i = start; i <= end; i ++)
-        if (sd->wp_groups[i])
+    for (i = start; i <= end; i++) {
+        if (sd->wp_groups[i >> 3] & (1 << (i & 0x7))) {
             sd->card_status |= WP_ERASE_SKIP;
+        }
+    }
 }
 
 static uint32_t sd_wpbits(SDState *sd, uint64_t addr)
@@ -496,9 +498,12 @@ static uint32_t sd_wpbits(SDState *sd, uint64_t addr)
 
     wpnum = addr >> (HWBLOCK_SHIFT + SECTOR_SHIFT + WPGROUP_SHIFT);
 
-    for (i = 0; i < 32; i ++, wpnum ++, addr += WPGROUP_SIZE)
-        if (addr < sd->size && sd->wp_groups[wpnum])
+    for (i = 0; i < 32; i++, wpnum++, addr += WPGROUP_SIZE) {
+        if (addr < sd->size &&
+                (sd->wp_groups[wpnum >> 3] & (1 << (wpnum & 0x7)))) {
             ret |= (1 << i);
+        }
+    }
 
     return ret;
 }
@@ -536,8 +541,9 @@ static void sd_function_switch(SDState *sd, uint32_t arg)
 
 static inline int sd_wp_addr(SDState *sd, uint32_t addr)
 {
-    return sd->wp_groups[addr >>
-            (HWBLOCK_SHIFT + SECTOR_SHIFT + WPGROUP_SHIFT)];
+    unsigned int grp = addr >>
+            (HWBLOCK_SHIFT + SECTOR_SHIFT + WPGROUP_SHIFT);
+    return sd->wp_groups[grp >> 3] & (1 << (grp & 0x7)) ? 1 : 0;
 }
 
 static void sd_lock_command(SDState *sd)
@@ -560,8 +566,8 @@ static void sd_lock_command(SDState *sd)
             sd->card_status |= LOCK_UNLOCK_FAILED;
             return;
         }
-        memset(sd->wp_groups, 0, sizeof(int) * (sd->size >>
-                        (HWBLOCK_SHIFT + SECTOR_SHIFT + WPGROUP_SHIFT)));
+        memset(sd->wp_groups, 0, 1 + (sd->size >>
+                        (HWBLOCK_SHIFT + SECTOR_SHIFT + WPGROUP_SHIFT + 3)));
         sd->csd[14] &= ~0x10;
         sd->card_status &= ~CARD_IS_LOCKED;
         sd->pwd_len = 0;
@@ -1007,8 +1013,9 @@ static sd_rsp_type_t sd_normal_command(SDState *sd,
             }
 
             sd->state = sd_programming_state;
-            sd->wp_groups[addr >> (HWBLOCK_SHIFT +
-                            SECTOR_SHIFT + WPGROUP_SHIFT)] = 1;
+            sd->wp_groups[addr >> (HWBLOCK_SHIFT + SECTOR_SHIFT +
+                    WPGROUP_SHIFT + 3)] |= 1 << ((addr >> (HWBLOCK_SHIFT +
+                            SECTOR_SHIFT + WPGROUP_SHIFT)) & 0x7);
             /* Bzzzzzzztt .... Operation complete.  */
             sd->state = sd_transfer_state;
             return sd_r1b;
@@ -1027,8 +1034,9 @@ static sd_rsp_type_t sd_normal_command(SDState *sd,
             }
 
             sd->state = sd_programming_state;
-            sd->wp_groups[addr >> (HWBLOCK_SHIFT +
-                            SECTOR_SHIFT + WPGROUP_SHIFT)] = 0;
+            sd->wp_groups[addr >> (HWBLOCK_SHIFT + SECTOR_SHIFT +
+                    WPGROUP_SHIFT + 3)] &= ~(1 << ((addr >> (HWBLOCK_SHIFT +
+                            SECTOR_SHIFT + WPGROUP_SHIFT)) & 0x7));
             /* Bzzzzzzztt .... Operation complete.  */
             sd->state = sd_transfer_state;
             return sd_r1b;
-- 
1.7.4.1