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