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device/pnp_device: rewrite pnp_get_ioresource

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The rewrite simplifies the code and fixes the limit on the case of IO resources
with the length of 1 byte.

This patch is inspired by the comment of Nico Huber on
Ia99b785dcd9cf56fb236ad7ade54656851f88a5e

If the ones in the mask aren't a continuous block, now a warning message gets
printed.

Change-Id: I0089278f5adf65e8f084580bc5bc1eb2f77b87f7
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-on: https://review.coreboot.org/27654
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
This commit is contained in:
Felix Held
2018-07-27 02:31:09 +02:00
parent 66ce18c508
commit f2ec648fcb
1 changed files with 23 additions and 32 deletions
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55
src/device/pnp_device.c
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@ -7,6 +7,7 @@
* Copyright (C) 2005 Tyan * Copyright (C) 2005 Tyan
* (Written by Yinghai Lu <yhlu@tyan.com> for Tyan) * (Written by Yinghai Lu <yhlu@tyan.com> for Tyan)
* Copyright (C) 2013 Nico Huber <nico.h@gmx.de> * Copyright (C) 2013 Nico Huber <nico.h@gmx.de>
* Copyright (C) 2018 Felix Held <felix-coreboot@felixheld.de>
* *
* This program is free software; you can redistribute it and/or modify * This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by * it under the terms of the GNU General Public License as published by
@ -194,8 +195,10 @@ struct device_operations pnp_ops = {
static void pnp_get_ioresource(struct device *dev, u8 index, u16 mask) static void pnp_get_ioresource(struct device *dev, u8 index, u16 mask)
{ {
struct resource *resource; struct resource *resource;
unsigned moving, gran, step; unsigned int bit;
/* If none of the mask bits is set, the resource would occupy the whole
IO space leading to IO resource conflicts with the other devices */
if (!mask) { if (!mask) {
printk(BIOS_ERR, "ERROR: device %s index %d has no mask.\n", printk(BIOS_ERR, "ERROR: device %s index %d has no mask.\n",
dev_path(dev), index); dev_path(dev), index);
@ -203,43 +206,31 @@ static void pnp_get_ioresource(struct device *dev, u8 index, u16 mask)
} }
resource = new_resource(dev, index); resource = new_resource(dev, index);
/* Initilize the resource. */
resource->limit = 0xffff;
resource->flags |= IORESOURCE_IO; resource->flags |= IORESOURCE_IO;
/* Get the resource size... */ /* Calculate IO region size which is determined by the first one from
the LSB of the mask. */
for (bit = 0; bit <= 15 && (mask & (1 << bit)) == 0; ++bit)
;
moving = mask; resource->gran = bit;
gran = 15; resource->align = bit;
step = 1 << gran; resource->size = 1 << bit;
/* Find the first bit that moves. */ /* Calculate IO region address limit which is determined by the first
while ((moving & step) == 0) { one from the MSB of the mask. */
gran--; for (bit = 15; bit != 0 && (mask & (1 << bit)) == 0; --bit)
step >>= 1; ;
}
/* Now find the first bit that does not move. */ resource->limit = (1 << (bit + 1)) - 1;
while ((moving & step) != 0) {
gran--;
step >>= 1;
}
/* /* The block of ones in the mask is expected to be continuous.
* Of the moving bits the last bit in the first group, If there is any zero inbetween the block of ones, it is ignored
* tells us the size of this resource. in the calculation of the resource size and limit. */
*/ if (mask != (resource->limit ^ (resource->size - 1)))
if ((moving & step) == 0) { printk(BIOS_WARNING,
gran++; "WARNING: mask of device %s index %d is wrong.\n",
step <<= 1; dev_path(dev), index);
}
/* Set the resource size and alignment. */
resource->gran = gran;
resource->align = gran;
resource->limit = mask | (step - 1);
resource->size = 1 << gran;
} }
static void get_resources(struct device *dev, struct pnp_info *info) static void get_resources(struct device *dev, struct pnp_info *info)