libata: make PMP support optional

Make PMP support optional by adding CONFIG_SATA_PMP and leaving out
libata-pmp.c if it isn't set.  PMP helpers return constant values if
PMP support is not enabled and PMP declarations alias non-PMP
counterparts.  This makes the compiler to leave out PMP related part
out and LLDs to use non-PMP counterparts automatically.

Signed-off-by: Tejun Heo <htejun@gmail.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 42b30e38495d..4aeeabb10a47 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -203,9 +203,26 @@ extern int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
 extern void ata_eh_finish(struct ata_port *ap);
 
 /* libata-pmp.c */
+#ifdef CONFIG_SATA_PMP
 extern int sata_pmp_scr_read(struct ata_link *link, int reg, u32 *val);
 extern int sata_pmp_scr_write(struct ata_link *link, int reg, u32 val);
 extern int sata_pmp_attach(struct ata_device *dev);
+#else /* CONFIG_SATA_PMP */
+static inline int sata_pmp_scr_read(struct ata_link *link, int reg, u32 *val)
+{
+        return -EINVAL;
+}
+
+static inline int sata_pmp_scr_write(struct ata_link *link, int reg, u32 val)
+{
+        return -EINVAL;
+}
+
+static inline int sata_pmp_attach(struct ata_device *dev)
+{
+        return -EINVAL;
+}
+#endif /* CONFIG_SATA_PMP */
 
 /* libata-sff.c */
 #ifdef CONFIG_ATA_SFF