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/*
* AMBA Plug & Play routines
*
* COPYRIGHT (c) 2011
* Aeroflex Gaisler
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#include <grlib/ambapp.h>
/* Calculate AHB Bus frequency of
* - Bus[0] (inverse=1), relative to the frequency of Bus[ahbidx]
* NOTE: set freq_hz to frequency of Bus[ahbidx].
* or
* - Bus[ahbidx] (inverse=0), relative to the frequency of Bus[0]
* NOTE: set freq_hz to frequency of Bus[0].
*
* If a unsupported bridge is found the invalid frequncy of 0Hz is
* returned.
*/
static unsigned int ambapp_freq_calc(
struct ambapp_bus *abus,
int ahbidx,
unsigned int freq_hz,
int inverse)
{
struct ambapp_ahb_info *ahb;
struct ambapp_dev *bridge;
unsigned char ffact;
int dir;
/* Found Bus0? */
bridge = abus->ahbs[ahbidx].bridge;
if (!bridge)
return freq_hz;
/* Find this bus frequency relative to freq_hz */
if ((bridge->vendor == VENDOR_GAISLER) &&
((bridge->device == GAISLER_AHB2AHB) ||
(bridge->device == GAISLER_L2CACHE))) {
ahb = DEV_TO_AHB(bridge);
ffact = (ahb->custom[0] & AMBAPP_FLAG_FFACT) >> 4;
if (ffact != 0) {
dir = ahb->custom[0] & AMBAPP_FLAG_FFACT_DIR;
/* Calculate frequency by dividing or
* multiplying system frequency
*/
if ((dir && !inverse) || (!dir && inverse))
freq_hz = freq_hz * ffact;
else
freq_hz = freq_hz / ffact;
}
return ambapp_freq_calc(abus, ahb->ahbidx, freq_hz, inverse);
} else {
/* Unknown bridge, impossible to calc frequency */
return 0;
}
}
/* Find the frequency of all AHB Buses from knowing the frequency of one
* particular APB/AHB Device.
*/
void ambapp_freq_init(
struct ambapp_bus *abus,
struct ambapp_dev *dev,
unsigned int freq_hz)
{
struct ambapp_common_info *info;
int i;
for (i=0; i<AHB_BUS_MAX; i++)
abus->ahbs[i].freq_hz = 0;
/* Register Frequency at the AHB bus that the device the user gave us
* is located at.
*/
if (dev) {
info = DEV_TO_COMMON(dev);
abus->ahbs[info->ahbidx].freq_hz = freq_hz;
/* Find Frequency of Bus 0 */
abus->ahbs[0].freq_hz = ambapp_freq_calc(abus, info->ahbidx, freq_hz, 1);
} else {
abus->ahbs[0].freq_hz = freq_hz;
}
/* Find Frequency of all except for Bus0 and the bus which frequency
* was reported at
*/
for (i=1; i<AHB_BUS_MAX; i++) {
if (abus->ahbs[i].ioarea == 0)
break;
if (abus->ahbs[i].freq_hz != 0)
continue;
abus->ahbs[i].freq_hz = ambapp_freq_calc(abus, i, abus->ahbs[0].freq_hz, 0);
}
}
/* Assign a AMBA Bus a frequency but reporting the frequency of a
* particular AHB/APB device */
unsigned int ambapp_freq_get(struct ambapp_bus *abus, struct ambapp_dev *dev)
{
struct ambapp_common_info *info = DEV_TO_COMMON(dev);
return abus->ahbs[info->ahbidx].freq_hz;
}
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