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/*
* Copyright (c) 2025 Ian Marco Moffett and L5 engineers
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the project nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Description: PCI base address register helpers
* Author: Ian Marco Moffett
*/
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/panic.h>
#include <io/pci/bar.h>
/*
* Get the size of a BAR
*/
ssize_t
pci_bar_size(struct pci_device *dev, uint8_t bar)
{
uint32_t reg_tmp, reg;
uint8_t barreg = pci_get_barreg(bar);
if (dev == NULL || barreg == 0) {
return -EINVAL;
}
/*
* A trick we can do to find the length of the BAR defined
* by the device is to see how many bits it is capable of
* decoding for a BAR then invert the mask as log2(length)
* bits must be unset.
*/
reg_tmp = pci_readl(dev, barreg);
pci_writel(dev, barreg, 0xFFFFFFFF);
reg = pci_readl(dev, barreg);
reg = ~reg + 1;
/* Restore and return the length */
pci_writel(dev, barreg, reg_tmp);
return reg;
}
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