On 2011-04-10 10:38, Jan Kiszka wrote:
> On 2011-04-03 22:16, Jordan Justen wrote:
>> When checking pfl->rom_mode for when to lazily reenter ROMD mode,
>> the value was check was the opposite of what it should have been.
>> This prevent the part from returning to ROMD mode after a write
>> was made to the CFI rom region.
>>
>> Signed-off-by: Jordan Justen <jordan.l.jus...@intel.com>
>> ---
>> hw/pflash_cfi02.c | 2 +-
>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/hw/pflash_cfi02.c b/hw/pflash_cfi02.c
>> index 30c8aa4..370c5ee 100644
>> --- a/hw/pflash_cfi02.c
>> +++ b/hw/pflash_cfi02.c
>> @@ -112,7 +112,7 @@ static uint32_t pflash_read (pflash_t *pfl,
>> target_phys_addr_t offset,
>>
>> DPRINTF("%s: offset " TARGET_FMT_plx "\n", __func__, offset);
>> ret = -1;
>> - if (pfl->rom_mode) {
>> + if (!pfl->rom_mode) {
>> /* Lazy reset of to ROMD mode */
>> if (pfl->wcycle == 0)
>> pflash_register_memory(pfl, 1);
>
> Indeed, that block looks weird to its author today as well. But
> inverting the logic completely defeats the purpose of lazy mode
> switching (will likely file a patch to remove the block). We should
> instead switch back using the timer.
That was wishful thinking. We were actually lacking a switch-back on
read, something that the old twisted logic was papering over. Patch
below should resolve that more gracefully, at least it does so here.
Jan
------8<------
Commit 5145b3d1cc revealed a bug in the lazy ROMD switch-back logic, but
resolved it by breaking that feature. This approach addresses the issue
by switching back to ROMD after a certain amount of read accesses
without further unlock sequences.
Signed-off-by: Jan Kiszka <jan.kis...@web.de>
---
hw/pflash_cfi02.c | 12 ++++++++----
1 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/hw/pflash_cfi02.c b/hw/pflash_cfi02.c
index 370c5ee..14bbc34 100644
--- a/hw/pflash_cfi02.c
+++ b/hw/pflash_cfi02.c
@@ -50,6 +50,8 @@ do { \
#define DPRINTF(fmt, ...) do { } while (0)
#endif
+#define PFLASH_LAZY_ROMD_THRESHOLD 42
+
struct pflash_t {
BlockDriverState *bs;
target_phys_addr_t base;
@@ -70,6 +72,7 @@ struct pflash_t {
ram_addr_t off;
int fl_mem;
int rom_mode;
+ int read_counter; /* used for lazy switch-back to rom mode */
void *storage;
};
@@ -112,10 +115,10 @@ static uint32_t pflash_read (pflash_t *pfl,
target_phys_addr_t offset,
DPRINTF("%s: offset " TARGET_FMT_plx "\n", __func__, offset);
ret = -1;
- if (!pfl->rom_mode) {
- /* Lazy reset of to ROMD mode */
- if (pfl->wcycle == 0)
- pflash_register_memory(pfl, 1);
+ /* Lazy reset to ROMD mode after a certain amount of read accesses */
+ if (!pfl->rom_mode && pfl->wcycle == 0 &&
+ ++pfl->read_counter > PFLASH_LAZY_ROMD_THRESHOLD) {
+ pflash_register_memory(pfl, 1);
}
offset &= pfl->chip_len - 1;
boff = offset & 0xFF;
@@ -254,6 +257,7 @@ static void pflash_write (pflash_t *pfl, target_phys_addr_t
offset,
/* Set the device in I/O access mode if required */
if (pfl->rom_mode)
pflash_register_memory(pfl, 0);
+ pfl->read_counter = 0;
/* We're in read mode */
check_unlock0:
if (boff == 0x55 && cmd == 0x98) {
--
1.7.1
