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authorJames Buren <braewoods+rb@braewoods.net>2020-10-29 02:11:29 +0000
committerWilliam Wilgus <me.theuser@yahoo.com>2020-10-29 05:30:28 +0000
commitf65e4104970b17cd9a69618da1997c5e523bef82 (patch)
tree6695bc8e4adb96b2580fca662017d144df87d5b2
parentc5c17fa7995c62267a1695e58841bd17b9fb2099 (diff)
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iriver_flash: rewrite how the flash commands wait for the ROM
This uses the toggle bit method referenced in the datasheets for the supported ROM chips and moves the code to a reusable subroutine. It also introduces a short delay to give the bus a chance to recover. The older ROM datasheet doesn't mention this delay as necessary but the newer one does so it now does this for both. Change-Id: Ie9dc8833bbd3ee545072b0c724ab220d13208d3d
-rw-r--r--apps/plugins/iriver_flash.c54
1 files changed, 30 insertions, 24 deletions
diff --git a/apps/plugins/iriver_flash.c b/apps/plugins/iriver_flash.c
index 2921ca0501..37bb3b3847 100644
--- a/apps/plugins/iriver_flash.c
+++ b/apps/plugins/iriver_flash.c
@@ -67,7 +67,7 @@ static volatile uint16_t* FB = (uint16_t*)0x00000000; /* Flash base address */
#endif
/* read the manufacturer and device ID */
-bool cfi_read_id(uint8_t* pManufacturerID, uint8_t* pDeviceID)
+static bool cfi_read_id(uint8_t* pManufacturerID, uint8_t* pDeviceID)
{
uint8_t not_manu, not_id; /* read values before switching to ID mode */
uint8_t manu, id; /* read values when in ID mode */
@@ -99,12 +99,34 @@ bool cfi_read_id(uint8_t* pManufacturerID, uint8_t* pDeviceID)
return false; /* fail */
}
+/* wait until the rom signals completion of an operation */
+static bool cfi_wait_for_rom(volatile uint16_t* pAddr)
+{
+ const unsigned MAX_TIMEOUT = 0xffffff; /* should be sufficient for most targets */
+ const unsigned RECOVERY_TIME = 64; /* based on 140MHz MCF 5249 */
+ uint16_t old_data = *pAddr & 0x0040; /* we only want DQ6 */
+ volatile unsigned i; /* disables certain optimizations */
+
+ /* repeat up to MAX_TIMEOUT times or until DQ6 stops flipping */
+ for (i = 0; i < MAX_TIMEOUT; i++)
+ {
+ uint16_t new_data = *pAddr & 0x0040; /* we only want DQ6 */
+ if(old_data == new_data)
+ break;
+ old_data = new_data;
+ }
+
+ bool result = i != MAX_TIMEOUT;
+
+ /* delay at least 1us to give the bus time to recover */
+ for (i = 0; i < RECOVERY_TIME; i++);
+
+ return result;
+}
/* erase the sector which contains the given address */
-bool cfi_erase_sector(volatile uint16_t* pAddr)
+static bool cfi_erase_sector(volatile uint16_t* pAddr)
{
- unsigned timeout = 430000; /* the timeout loop should be no less than 25ms */
-
FB[0x5555] = 0xAA; /* enter command mode */
FB[0x2AAA] = 0x55;
FB[0x5555] = 0x80; /* erase command */
@@ -112,36 +134,20 @@ bool cfi_erase_sector(volatile uint16_t* pAddr)
FB[0x2AAA] = 0x55;
*pAddr = 0x30; /* erase the sector */
- /* I counted 7 instructions for this loop -> min. 0.58 us per round */
- /* Plus memory waitstates it will be much more, gives margin */
- while (*pAddr != 0xFFFF && --timeout); /* poll for erased */
-
- return (timeout != 0);
+ return cfi_wait_for_rom(pAddr);
}
-
/* address must be in an erased location */
-static inline bool cfi_program_word(volatile uint16_t* pAddr, uint16_t data)
+static bool cfi_program_word(volatile uint16_t* pAddr, uint16_t data)
{
- unsigned timeout = 85; /* the timeout loop should be no less than 20us */
-
- if (~*pAddr & data) /* just a safety feature, not really necessary */
- return false; /* can't set any bit from 0 to 1 */
-
FB[0x5555] = 0xAA; /* enter command mode */
FB[0x2AAA] = 0x55;
FB[0x5555] = 0xA0; /* byte program command */
+ *pAddr = data; /* write the word data */
- *pAddr = data;
-
- /* I counted 7 instructions for this loop -> min. 0.58 us per round */
- /* Plus memory waitstates it will be much more, gives margin */
- while (*pAddr != data && --timeout); /* poll for programmed */
-
- return (timeout != 0);
+ return cfi_wait_for_rom(pAddr);
}
-
/* this returns true if supported and fills the info struct */
bool cfi_get_flash_info(struct flash_info* pInfo)
{