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iriver_flash: rewrite how the flash commands wait for the ROM

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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
This commit is contained in:
James Buren 2020-10-29 02:11:29 +00:00 • committed by William Wilgus
parent c5c17fa799
commit f65e410497
1 changed files with 30 additions and 24 deletions
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54
apps/plugins/iriver_flash.c
View file

@ -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)
{