Patchwork [v3,5/9] fdc: add CCR (Configuration Control Register) write register

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Submitter Hervé Poussineau
Date Jan. 23, 2012, 8:50 a.m.
Message ID <1327308641-14736-6-git-send-email-hpoussin@reactos.org>
Download mbox | patch
Permalink /patch/137319/
State New
Headers show

Comments

Hervé Poussineau - Jan. 23, 2012, 8:50 a.m.
DIR and CCR registers share the same address ; DIR is read-only
while CCR is write-only

Signed-off-by: Hervé Poussineau <hpoussin@reactos.org>
---
 hw/fdc.c |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)
Markus Armbruster - Jan. 27, 2012, 8:43 a.m.
Hervé Poussineau <hpoussin@reactos.org> writes:

> DIR and CCR registers share the same address ; DIR is read-only
> while CCR is write-only

Looks like guest writes to CCR are silently ignored before this patch.
Is that correct?  Impact?
Hervé Poussineau - Jan. 27, 2012, 8:03 p.m.
Markus Armbruster a écrit :
> Hervé Poussineau <hpoussin@reactos.org> writes:
> 
>> DIR and CCR registers share the same address ; DIR is read-only
>> while CCR is write-only
> 
> Looks like guest writes to CCR are silently ignored before this patch.
> Is that correct?  

Yes.

> Impact?

CCR is only used to program media rate, which is not checked without 
this patchset.

So, none for this patch.
Markus Armbruster - Jan. 31, 2012, 9:31 a.m.
Hervé Poussineau <hpoussin@reactos.org> writes:

> Markus Armbruster a écrit :
>> Hervé Poussineau <hpoussin@reactos.org> writes:
>>
>>> DIR and CCR registers share the same address ; DIR is read-only
>>> while CCR is write-only
>>
>> Looks like guest writes to CCR are silently ignored before this patch.
>> Is that correct?  
>
> Yes.
>
>> Impact?
>
> CCR is only used to program media rate, which is not checked without
> this patchset.
>
> So, none for this patch.

Aha, it's just a prerequisite for the rest of the series.  Makes sense.

Explain in commit message?
Hervé Poussineau - Jan. 31, 2012, 10:16 p.m.
Markus Armbruster a écrit :
> Hervé Poussineau <hpoussin@reactos.org> writes:
> 
>> Markus Armbruster a écrit :
>>> Hervé Poussineau <hpoussin@reactos.org> writes:
>>>
>>>> DIR and CCR registers share the same address ; DIR is read-only
>>>> while CCR is write-only
>>> Looks like guest writes to CCR are silently ignored before this patch.
>>> Is that correct?  
>> Yes.
>>
>>> Impact?
>> CCR is only used to program media rate, which is not checked without
>> this patchset.
>>
>> So, none for this patch.
> 
> Aha, it's just a prerequisite for the rest of the series.  Makes sense.
> 
> Explain in commit message?
> 

Will do when respinning the serie

Hervé

Patch

diff --git a/hw/fdc.c b/hw/fdc.c
index 4a363bd..4875291 100644
--- a/hw/fdc.c
+++ b/hw/fdc.c
@@ -224,6 +224,7 @@  static void fdctrl_write_rate(FDCtrl *fdctrl, uint32_t value);
 static uint32_t fdctrl_read_data(FDCtrl *fdctrl);
 static void fdctrl_write_data(FDCtrl *fdctrl, uint32_t value);
 static uint32_t fdctrl_read_dir(FDCtrl *fdctrl);
+static void fdctrl_write_ccr(FDCtrl *fdctrl, uint32_t value);
 
 enum {
     FD_DIR_WRITE   = 0,
@@ -248,6 +249,7 @@  enum {
     FD_REG_DSR = 0x04,
     FD_REG_FIFO = 0x05,
     FD_REG_DIR = 0x07,
+    FD_REG_CCR = 0x07,
 };
 
 enum {
@@ -491,6 +493,9 @@  static void fdctrl_write (void *opaque, uint32_t reg, uint32_t value)
     case FD_REG_FIFO:
         fdctrl_write_data(fdctrl, value);
         break;
+    case FD_REG_CCR:
+        fdctrl_write_ccr(fdctrl, value);
+        break;
     default:
         break;
     }
@@ -881,6 +886,23 @@  static void fdctrl_write_rate(FDCtrl *fdctrl, uint32_t value)
     fdctrl->dsr = value;
 }
 
+/* Configuration control register: 0x07 (write) */
+static void fdctrl_write_ccr(FDCtrl *fdctrl, uint32_t value)
+{
+    /* Reset mode */
+    if (!(fdctrl->dor & FD_DOR_nRESET)) {
+        FLOPPY_DPRINTF("Floppy controller in RESET state !\n");
+        return;
+    }
+    FLOPPY_DPRINTF("configuration control register set to 0x%02x\n", value);
+
+    /* Only the rate selection bits used in AT mode, and we
+     * store those in the DSR.
+     */
+    fdctrl->dsr = (fdctrl->dsr & ~FD_DSR_DRATEMASK) |
+                  (value & FD_DSR_DRATEMASK);
+}
+
 static int fdctrl_media_changed(FDrive *drv)
 {
     int ret;