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Subject[PATCH] floppy: request and release only the ports we actually use
Andrew,

this is a combined patch replacing the following ones currently in
the -mm tree :
floppy-request-only-the-ports-we-actually-use.patch
floppy-request-only-the-ports-we-actually-use-fix.patch

Bjorn,

Since you did the hard job of collecting the used io-ports and writing
the changelog and part of this patch, I kept your Signed-off-by :

Philippe

--

The floppy driver requests an I/O port it doesn't need, and
sometimes this causes a conflict with a motherboard device
reported by PNPBIOS.

This patch makes the floppy driver request and release
only the ports it actually uses. It also factors out
the request/release stuff and the io-ports list so
they're all in one place now.

The current floppy driver uses only these ports:
0x3f2 (FD_DOR)
0x3f4 (FD_STATUS)
0x3f5 (FD_DATA)
0x3f7 (FD_DCR/FD_DIR)
but it requests 0x3f2-0x3f5 and 0x3f7, which includes the
unused port 0x3f3.

Some BIOSes report 0x3f3 as a motherboard resource. The PNP system
driver reserves that, which causes a conflict when the floppy driver
requests 0x3f2-0x3f5 later.

Philippe reported that this conflict broke the floppy driver between
2.6.11 and 2.6.22. His PNPBIOS reports these devices:

$ cat 00:07/id 00:07/resources # motherboard device
PNP0c02
state = active
io 0x80-0x80
io 0x10-0x1f
io 0x22-0x3f
io 0x44-0x5f
io 0x90-0x9f
io 0xa2-0xbf
io 0x3f0-0x3f1
io 0x3f3-0x3f3

$ cat 00:03/id 00:03/resources # floppy device
PNP0700
state = active
io 0x3f4-0x3f5
io 0x3f2-0x3f2

Reference:
http://lkml.org/lkml/2009/1/31/162

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Philippe De Muyter <phdm@macqel.be>
Reported-by: Philippe De Muyter <phdm@macqel.be>
Tested-by: Philippe De Muyter <phdm@macqel.be>
CC: Adam M Belay <abelay@mit.edu>
CC: Robert Hancock <hancockrwd@gmail.com>
---
diff -r 94166a3a38bd drivers/block/floppy.c
--- a/drivers/block/floppy.c Sat Jan 31 15:56:23 2009 -0800
+++ b/drivers/block/floppy.c Fri Feb 13 09:24:51 2009 +0100
@@ -558,6 +558,8 @@ static void recalibrate_floppy(void);
static void recalibrate_floppy(void);
static void floppy_shutdown(unsigned long);

+static int floppy_request_regions(int);
+static void floppy_release_regions(int);
static int floppy_grab_irq_and_dma(void);
static void floppy_release_irq_and_dma(void);

@@ -4274,8 +4276,7 @@ static int __init floppy_init(void)
FDCS->rawcmd = 2;
if (user_reset_fdc(-1, FD_RESET_ALWAYS, 0)) {
/* free ioports reserved by floppy_grab_irq_and_dma() */
- release_region(FDCS->address + 2, 4);
- release_region(FDCS->address + 7, 1);
+ floppy_release_regions(fdc);
FDCS->address = -1;
FDCS->version = FDC_NONE;
continue;
@@ -4284,8 +4285,7 @@ static int __init floppy_init(void)
FDCS->version = get_fdc_version();
if (FDCS->version == FDC_NONE) {
/* free ioports reserved by floppy_grab_irq_and_dma() */
- release_region(FDCS->address + 2, 4);
- release_region(FDCS->address + 7, 1);
+ floppy_release_regions(fdc);
FDCS->address = -1;
continue;
}
@@ -4358,6 +4358,47 @@ out_put_disk:

static DEFINE_SPINLOCK(floppy_usage_lock);

+static const struct io_region {
+ int offset;
+ int size;
+} io_regions[] = {
+ { 2, 1 },
+ /* address + 3 is sometimes reserved by pnp bios for motherboard */
+ { 4, 2 },
+ /* address + 6 is reserved, and may be taken by IDE.
+ * Unfortunately, Adaptec doesn't know this :-(, */
+ { 7, 1 },
+};
+
+static void floppy_release_allocated_regions(int fdc, const struct io_region *p)
+{
+ while (p != io_regions) {
+ p--;
+ release_region(FDCS->address + p->offset, p->size);
+ }
+}
+
+#define ARRAY_END(X) (&((X)[ARRAY_SIZE(X)]))
+
+static int floppy_request_regions(int fdc)
+{
+ const struct io_region *p;
+
+ for (p = io_regions; p < ARRAY_END(io_regions); p++) {
+ if (!request_region(FDCS->address + p->offset, p->size, "floppy")) {
+ DPRINT("Floppy io-port 0x%04lx in use\n", FDCS->address + p->offset);
+ floppy_release_allocated_regions(fdc, p);
+ return -EBUSY;
+ }
+ }
+ return 0;
+}
+
+static void floppy_release_regions(int fdc)
+{
+ floppy_release_allocated_regions(fdc, ARRAY_END(io_regions));
+}
+
static int floppy_grab_irq_and_dma(void)
{
unsigned long flags;
@@ -4399,18 +4440,8 @@ static int floppy_grab_irq_and_dma(void)

for (fdc = 0; fdc < N_FDC; fdc++) {
if (FDCS->address != -1) {
- if (!request_region(FDCS->address + 2, 4, "floppy")) {
- DPRINT("Floppy io-port 0x%04lx in use\n",
- FDCS->address + 2);
- goto cleanup1;
- }
- if (!request_region(FDCS->address + 7, 1, "floppy DIR")) {
- DPRINT("Floppy io-port 0x%04lx in use\n",
- FDCS->address + 7);
- goto cleanup2;
- }
- /* address + 6 is reserved, and may be taken by IDE.
- * Unfortunately, Adaptec doesn't know this :-(, */
+ if (floppy_request_regions(fdc))
+ goto cleanup;
}
}
for (fdc = 0; fdc < N_FDC; fdc++) {
@@ -4432,15 +4463,11 @@ static int floppy_grab_irq_and_dma(void)
fdc = 0;
irqdma_allocated = 1;
return 0;
-cleanup2:
- release_region(FDCS->address + 2, 4);
-cleanup1:
+cleanup:
fd_free_irq();
fd_free_dma();
- while (--fdc >= 0) {
- release_region(FDCS->address + 2, 4);
- release_region(FDCS->address + 7, 1);
- }
+ while (--fdc >= 0)
+ floppy_release_regions(fdc);
spin_lock_irqsave(&floppy_usage_lock, flags);
usage_count--;
spin_unlock_irqrestore(&floppy_usage_lock, flags);
@@ -4501,10 +4528,8 @@ static void floppy_release_irq_and_dma(v
#endif
old_fdc = fdc;
for (fdc = 0; fdc < N_FDC; fdc++)
- if (FDCS->address != -1) {
- release_region(FDCS->address + 2, 4);
- release_region(FDCS->address + 7, 1);
- }
+ if (FDCS->address != -1)
+ floppy_release_regions(fdc);
fdc = old_fdc;
}


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