Some Mac models have an IOP for offloading floppy disk IO. Linux once
had a driver for that but it got removed in commit b21a323710e7
("[PATCH] remove the broken BLK_DEV_SWIM_IOP driver").

Put the ISM IOP into bypass mode so that the existing 'swim_mod' driver
can access the controller directly. Use the appropriate macros for the
flag bits.

Cc: Laurent Vivier <lviv...@redhat.com>
Tested-by: Stan Johnson <user...@yahoo.com>
Signed-off-by: Finn Thain <fth...@telegraphics.com.au>
---
 arch/m68k/mac/iop.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/m68k/mac/iop.c b/arch/m68k/mac/iop.c
index 9bfa17015768..7864dcca5891 100644
--- a/arch/m68k/mac/iop.c
+++ b/arch/m68k/mac/iop.c
@@ -234,6 +234,7 @@ static struct iop_msg *iop_get_unused_msg(void)
  * is to find and initialize the IOPs early in the boot sequence, so that
  * the serial IOP can be placed into bypass mode _before_ we try to
  * initialize the serial console.
+ * The ISM IOP is put into bypass mode for compatibility with the swim driver.
  */
 
 void __init iop_preinit(void)
@@ -244,7 +245,8 @@ void __init iop_preinit(void)
                } else {
                        iop_base[IOP_NUM_SCC] = (struct mac_iop *) 
SCC_IOP_BASE_QUADRA;
                }
-               iop_base[IOP_NUM_SCC]->status_ctrl = 0x87;
+               iop_base[IOP_NUM_SCC]->status_ctrl = IOP_BYPASS | IOP_AUTOINC |
+                                                    IOP_RUN | IOP_DMAINACTIVE;
                iop_scc_present = 1;
        } else {
                iop_base[IOP_NUM_SCC] = NULL;
@@ -256,7 +258,8 @@ void __init iop_preinit(void)
                } else {
                        iop_base[IOP_NUM_ISM] = (struct mac_iop *) 
ISM_IOP_BASE_QUADRA;
                }
-               iop_base[IOP_NUM_ISM]->status_ctrl = 0;
+               iop_base[IOP_NUM_ISM]->status_ctrl = IOP_BYPASS | IOP_AUTOINC |
+                                                    IOP_RUN | IOP_DMAINACTIVE;
                iop_ism_present = 1;
        } else {
                iop_base[IOP_NUM_ISM] = NULL;
-- 
2.16.1

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