79853d2b28
With both counters in place, the number of bytes in the buffer is now indicated by the difference between the M0 and M4 counts. The M4 count needs to be increased whenever the M4 produces or consumes data in the USB bulk buffer, so that the two counts remain correctly synchronised. There are three places where this is done: 1. When a USB bulk transfer in or out of the buffer completes, the count is increased by the number of bytes transferred. This is the most common case. 2. At TX startup, the M4 effectively sends the M0 16K of zeroes to transmit, before the first host-provided data. This is done by zeroing the whole 32K buffer area, and then setting up the first bulk transfer to write to the second 16K, whilst the M0 begins transmission of the first 16K. The count is therefore increased by 16K during TX startup, to account for the initial 16K of zeros. 3. In sweep mode, some data is discarded. When this is done, the count is incremented by the size of the discarded data. The USB IRQ is masked whilst doing this, since a read-modify-write is required, and the bulk transfer completion callback may be called at any point, which also increases the count.
44 lines
1.3 KiB
C
44 lines
1.3 KiB
C
/*
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* Copyright 2022 Great Scott Gadgets
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*
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* This file is part of HackRF.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef __M0_STATE_H__
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#define __M0_STATE_H__
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#include <stdint.h>
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#include <usb_request.h>
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struct m0_state {
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uint32_t m0_count;
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uint32_t m4_count;
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uint32_t tx;
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};
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/* Address of m0_state is set in ldscripts. If you change the name of this
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* variable, it won't be where it needs to be in the processor's address space,
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* unless you also adjust the ldscripts.
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*/
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extern volatile struct m0_state m0_state;
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usb_request_status_t usb_vendor_request_get_m0_state(
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usb_endpoint_t* const endpoint, const usb_transfer_stage_t stage);
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#endif/*__M0_STATE_H__*/
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