From 661bfc80e876d32da8befe53ba0234d87fc0bcc2 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Sun, 10 Apr 2011 12:53:39 +0200 Subject: pflash: Restore & fix lazy ROMD switching 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 Signed-off-by: Aurelien Jarno --- hw/pflash_cfi02.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'hw/pflash_cfi02.c') 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) { -- cgit v1.1