static u32 sil24_scr_read(struct ata_port *ap, unsigned sc_reg);
static void sil24_scr_write(struct ata_port *ap, unsigned sc_reg, u32 val);
static void sil24_tf_read(struct ata_port *ap, struct ata_taskfile *tf);
static u32 sil24_scr_read(struct ata_port *ap, unsigned sc_reg);
static void sil24_scr_write(struct ata_port *ap, unsigned sc_reg, u32 val);
static void sil24_tf_read(struct ata_port *ap, struct ata_taskfile *tf);