Dieter Graef / USBHost_DISCO-F746NG

Simple USBHost library for STM32F746NG Discovery board. Only either the Fastspeed or the Highspeed port can be used( not both together)

Dependents:   DISCO-F746NG_USB_Host

Fork of KL46Z-USBHost by Norimasa Okamoto

USBHost/USB_Helper.c@24:5396b6a93262, 2016-06-13 (annotated)

Committer:
DieterGraef
Date:
Mon Jun 13 17:21:07 2016 +0000
Revision:
24:5396b6a93262
USB Host for STM32F746 DISCO Board. At the moment you can only use either the High Speed Port or the Fast Speed Port.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
DieterGraef 24:5396b6a93262 1 #include "USB_Helper.h"
DieterGraef 24:5396b6a93262 2
DieterGraef 24:5396b6a93262 3 /* cache flush */
DieterGraef 24:5396b6a93262 4 void CPU_CACHE_Flush(uint32_t * buffer, uint32_t length)
DieterGraef 24:5396b6a93262 5 {
DieterGraef 24:5396b6a93262 6 // SCB_InvalidateDCache_by_Addr(buffer,length);
DieterGraef 24:5396b6a93262 7 uint32_t ccsidr;
DieterGraef 24:5396b6a93262 8 uint32_t smask;
DieterGraef 24:5396b6a93262 9 uint32_t sshift;
DieterGraef 24:5396b6a93262 10 uint32_t ways;
DieterGraef 24:5396b6a93262 11 uint32_t wshift;
DieterGraef 24:5396b6a93262 12 uint32_t ssize;
DieterGraef 24:5396b6a93262 13 uint32_t sets;
DieterGraef 24:5396b6a93262 14 uint32_t sw;
DieterGraef 24:5396b6a93262 15 uint32_t start;
DieterGraef 24:5396b6a93262 16 uint32_t ende;
DieterGraef 24:5396b6a93262 17
DieterGraef 24:5396b6a93262 18 start=(uint32_t)buffer;
DieterGraef 24:5396b6a93262 19 ende=start+length;
DieterGraef 24:5396b6a93262 20 /* Get the characteristics of the D-Cache */
DieterGraef 24:5396b6a93262 21
DieterGraef 24:5396b6a93262 22 ccsidr = SCB->CCSIDR;
DieterGraef 24:5396b6a93262 23 smask = CCSIDR_SETS(ccsidr); /* (Number of sets) - 1 */
DieterGraef 24:5396b6a93262 24 sshift = CCSIDR_LSSHIFT(ccsidr) + 4; /* log2(cache-line-size-in-bytes) */
DieterGraef 24:5396b6a93262 25 ways = CCSIDR_WAYS(ccsidr); /* (Number of ways) - 1 */
DieterGraef 24:5396b6a93262 26
DieterGraef 24:5396b6a93262 27 /* Calculate the bit offset for the way field in the DCCISW register by
DieterGraef 24:5396b6a93262 28 * counting the number of leading zeroes. For example:
DieterGraef 24:5396b6a93262 29 *
DieterGraef 24:5396b6a93262 30 * Number of Value of ways Field
DieterGraef 24:5396b6a93262 31 * Ways 'ways' Offset
DieterGraef 24:5396b6a93262 32 * 2 1 31
DieterGraef 24:5396b6a93262 33 * 4 3 30
DieterGraef 24:5396b6a93262 34 * 8 7 29
DieterGraef 24:5396b6a93262 35 * ...
DieterGraef 24:5396b6a93262 36 */
DieterGraef 24:5396b6a93262 37
DieterGraef 24:5396b6a93262 38 wshift = __CLZ(ways) & 0x1f;
DieterGraef 24:5396b6a93262 39
DieterGraef 24:5396b6a93262 40 /* Clean and invalidate the D-Cache over the range of addresses */
DieterGraef 24:5396b6a93262 41
DieterGraef 24:5396b6a93262 42 ssize = (1 << sshift);
DieterGraef 24:5396b6a93262 43 start &= ~(ssize - 1);
DieterGraef 24:5396b6a93262 44 __DSB();
DieterGraef 24:5396b6a93262 45
DieterGraef 24:5396b6a93262 46 do
DieterGraef 24:5396b6a93262 47 {
DieterGraef 24:5396b6a93262 48 int32_t tmpways = ways;
DieterGraef 24:5396b6a93262 49
DieterGraef 24:5396b6a93262 50 /* Isolate the cache line associated with this address. For example
DieterGraef 24:5396b6a93262 51 * if the cache line size is 32 bytes and the cache size is 16KB, then
DieterGraef 24:5396b6a93262 52 *
DieterGraef 24:5396b6a93262 53 * sshift = 5 : Offset to the beginning of the set field
DieterGraef 24:5396b6a93262 54 * smask = 0x007f : Mask of the set field
DieterGraef 24:5396b6a93262 55 */
DieterGraef 24:5396b6a93262 56
DieterGraef 24:5396b6a93262 57 sets = ((uint32_t)start >> sshift) & smask;
DieterGraef 24:5396b6a93262 58
DieterGraef 24:5396b6a93262 59 /* Clean and invalidate each way for this cacheline */
DieterGraef 24:5396b6a93262 60
DieterGraef 24:5396b6a93262 61 do
DieterGraef 24:5396b6a93262 62 {
DieterGraef 24:5396b6a93262 63 sw = ((tmpways << wshift) | (sets << sshift));
DieterGraef 24:5396b6a93262 64 SCB->DCCISW=sw;
DieterGraef 24:5396b6a93262 65
DieterGraef 24:5396b6a93262 66 }
DieterGraef 24:5396b6a93262 67 while (tmpways--);
DieterGraef 24:5396b6a93262 68
DieterGraef 24:5396b6a93262 69 /* Increment the address by the size of one cache line. */
DieterGraef 24:5396b6a93262 70
DieterGraef 24:5396b6a93262 71 start += ssize;
DieterGraef 24:5396b6a93262 72 }
DieterGraef 24:5396b6a93262 73 while (start < ende);
DieterGraef 24:5396b6a93262 74
DieterGraef 24:5396b6a93262 75 __DSB();
DieterGraef 24:5396b6a93262 76 __ISB();
DieterGraef 24:5396b6a93262 77 }