diff mbox series

[v3,2/6] soc/fsl/qe: qe.c: reduce static memory footprint by1.7K

Message ID 20190513111442.25724-3-rasmus.villemoes@prevas.dk (mailing list archive)
State Not Applicable
Headers show
Series [v3,1/6] soc/fsl/qe: qe.c: drop useless static qualifier | expand

Checks

Context Check Description
snowpatch_ozlabs/apply_patch success Successfully applied on branch next (8150a153c013aa2dd1ffae43370b89ac1347a7fb)
snowpatch_ozlabs/checkpatch success total: 0 errors, 0 warnings, 0 checks, 79 lines checked

Commit Message

Rasmus Villemoes May 13, 2019, 11:14 a.m. UTC 
The current array of struct qe_snum use 256*4 bytes for just keeping
track of the free/used state of each index, and the struct layout
means there's another 768 bytes of padding. If we just unzip that
structure, the array of snum values just use 256 bytes, while the
free/inuse state can be tracked in a 32 byte bitmap.

So this reduces the .data footprint by 1760 bytes. It also serves as
preparation for introducing another DT binding for specifying the snum
values.

Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Qiang Zhao <qiang.zhao@nxp.com>
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
---
 drivers/soc/fsl/qe/qe.c | 42 ++++++++++++-----------------------------
 1 file changed, 12 insertions(+), 30 deletions(-)
diff mbox series

Patch

diff --git a/drivers/soc/fsl/qe/qe.c b/drivers/soc/fsl/qe/qe.c
index 855373deb746..4b59109df22b 100644
--- a/drivers/soc/fsl/qe/qe.c
+++ b/drivers/soc/fsl/qe/qe.c
@@ -14,6 +14,7 @@ 
  * Free Software Foundation;  either version 2 of the  License, or (at your
  * option) any later version.
  */
+#include <linux/bitmap.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
@@ -43,25 +44,14 @@  static DEFINE_SPINLOCK(qe_lock);
 DEFINE_SPINLOCK(cmxgcr_lock);
 EXPORT_SYMBOL(cmxgcr_lock);
 
-/* QE snum state */
-enum qe_snum_state {
-	QE_SNUM_STATE_USED,
-	QE_SNUM_STATE_FREE
-};
-
-/* QE snum */
-struct qe_snum {
-	u8 num;
-	enum qe_snum_state state;
-};
-
 /* We allocate this here because it is used almost exclusively for
  * the communication processor devices.
  */
 struct qe_immap __iomem *qe_immr;
 EXPORT_SYMBOL(qe_immr);
 
-static struct qe_snum snums[QE_NUM_OF_SNUM];	/* Dynamically allocated SNUMs */
+static u8 snums[QE_NUM_OF_SNUM];	/* Dynamically allocated SNUMs */
+static DECLARE_BITMAP(snum_state, QE_NUM_OF_SNUM);
 static unsigned int qe_num_of_snum;
 
 static phys_addr_t qebase = -1;
@@ -315,10 +305,8 @@  static void qe_snums_init(void)
 	else
 		snum_init = snum_init_46;
 
-	for (i = 0; i < qe_num_of_snum; i++) {
-		snums[i].num = snum_init[i];
-		snums[i].state = QE_SNUM_STATE_FREE;
-	}
+	bitmap_zero(snum_state, QE_NUM_OF_SNUM);
+	memcpy(snums, snum_init, qe_num_of_snum);
 }
 
 int qe_get_snum(void)
@@ -328,12 +316,10 @@  int qe_get_snum(void)
 	int i;
 
 	spin_lock_irqsave(&qe_lock, flags);
-	for (i = 0; i < qe_num_of_snum; i++) {
-		if (snums[i].state == QE_SNUM_STATE_FREE) {
-			snums[i].state = QE_SNUM_STATE_USED;
-			snum = snums[i].num;
-			break;
-		}
+	i = find_first_zero_bit(snum_state, qe_num_of_snum);
+	if (i < qe_num_of_snum) {
+		set_bit(i, snum_state);
+		snum = snums[i];
 	}
 	spin_unlock_irqrestore(&qe_lock, flags);
 
@@ -343,14 +329,10 @@  EXPORT_SYMBOL(qe_get_snum);
 
 void qe_put_snum(u8 snum)
 {
-	int i;
+	const u8 *p = memchr(snums, snum, qe_num_of_snum);
 
-	for (i = 0; i < qe_num_of_snum; i++) {
-		if (snums[i].num == snum) {
-			snums[i].state = QE_SNUM_STATE_FREE;
-			break;
-		}
-	}
+	if (p)
+		clear_bit(p - snums, snum_state);
 }
 EXPORT_SYMBOL(qe_put_snum);