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linux-next/drivers/pnp/manager.c
David Flater bdf0eb3a02 pnp: restore automatic resolution of DMA conflicts 
To fix a 5-year-old regression, reverse changes made by commit
7ef3639 (PNP: don't fail device init if no DMA channel available).

As an example to show the problem, my sound card provides a
prioritized list of PnP "dependent sets" of requested resources:

  dependent set 0 (preferred) wants DMA 5.
  dependent set 1 (acceptable) will take DMA 5, 6, or 7.
  ...
  dependent set 4 (acceptable) doesn't request a high DMA.

If DMA 5 is not available, pnp_assign_dma has to fail on set 0 so that
pnp_auto_config_dev will move on to set 1 and get DMA 6 or 7.
Instead, pnp_assign_dma adds the resource with flags |=
IORESOURCE_DISABLED and returns success.  pnp_auto_config_dev just
sees success and therefore chooses set 0 with a disabled DMA and never
tries the sets that would have resolved the conflict.

Furthermore, this mode of "success" is unexpected and unhandled in
sound/isa/sb and probably other drivers.  sb assumes that the returned
DMA is enabled and obliviously uses the invalid DMA number.  Observed
consequences were sb successfully grabbing a DMA that was expressly
forbidden by the kernel parameter pnp_reserve_dma.

The only upside to the original change would be as a kludge for
devices that can operate in degraded mode without a DMA but that don't
provide the corresponding non-preferred dependent set.  The right
workaround for those devices is to synthesize the missing set in
quirks.c; otherwise, you're reinventing PnP fallback functionality at
the driver level for that device and all others.

Signed-off-by: David Flater <dave@flaterco.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-05-22 00:21:02 +02:00

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9.9 KiB
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/*
* manager.c - Resource Management, Conflict Resolution, Activation and Disabling of Devices
*
* based on isapnp.c resource management (c) Jaroslav Kysela <perex@perex.cz>
* Copyright 2003 Adam Belay <ambx1@neo.rr.com>
* Copyright (C) 2008 Hewlett-Packard Development Company, L.P.
* Bjorn Helgaas <bjorn.helgaas@hp.com>
*/
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/pnp.h>
#include <linux/bitmap.h>
#include <linux/mutex.h>
#include "base.h"
DEFINE_MUTEX(pnp_res_mutex);
static struct resource *pnp_find_resource(struct pnp_dev *dev,
unsigned char rule,
unsigned long type,
unsigned int bar)
{
struct resource *res = pnp_get_resource(dev, type, bar);
/* when the resource already exists, set its resource bits from rule */
if (res) {
res->flags &= ~IORESOURCE_BITS;
res->flags |= rule & IORESOURCE_BITS;
}
return res;
}
static int pnp_assign_port(struct pnp_dev *dev, struct pnp_port *rule, int idx)
{
struct resource *res, local_res;
res = pnp_find_resource(dev, rule->flags, IORESOURCE_IO, idx);
if (res) {
pnp_dbg(&dev->dev, " io %d already set to %#llx-%#llx "
"flags %#lx\n", idx, (unsigned long long) res->start,
(unsigned long long) res->end, res->flags);
return 0;
}
res = &local_res;
res->flags = rule->flags | IORESOURCE_AUTO;
res->start = 0;
res->end = 0;
if (!rule->size) {
res->flags |= IORESOURCE_DISABLED;
pnp_dbg(&dev->dev, " io %d disabled\n", idx);
goto __add;
}
res->start = rule->min;
res->end = res->start + rule->size - 1;
while (!pnp_check_port(dev, res)) {
res->start += rule->align;
res->end = res->start + rule->size - 1;
if (res->start > rule->max || !rule->align) {
pnp_dbg(&dev->dev, " couldn't assign io %d "
"(min %#llx max %#llx)\n", idx,
(unsigned long long) rule->min,
(unsigned long long) rule->max);
return -EBUSY;
}
}
__add:
pnp_add_io_resource(dev, res->start, res->end, res->flags);
return 0;
}
static int pnp_assign_mem(struct pnp_dev *dev, struct pnp_mem *rule, int idx)
{
struct resource *res, local_res;
res = pnp_find_resource(dev, rule->flags, IORESOURCE_MEM, idx);
if (res) {
pnp_dbg(&dev->dev, " mem %d already set to %#llx-%#llx "
"flags %#lx\n", idx, (unsigned long long) res->start,
(unsigned long long) res->end, res->flags);
return 0;
}
res = &local_res;
res->flags = rule->flags | IORESOURCE_AUTO;
res->start = 0;
res->end = 0;
/* ??? rule->flags restricted to 8 bits, all tests bogus ??? */
if (!(rule->flags & IORESOURCE_MEM_WRITEABLE))
res->flags |= IORESOURCE_READONLY;
if (rule->flags & IORESOURCE_MEM_CACHEABLE)
res->flags |= IORESOURCE_CACHEABLE;
if (rule->flags & IORESOURCE_MEM_RANGELENGTH)
res->flags |= IORESOURCE_RANGELENGTH;
if (rule->flags & IORESOURCE_MEM_SHADOWABLE)
res->flags |= IORESOURCE_SHADOWABLE;
if (!rule->size) {
res->flags |= IORESOURCE_DISABLED;
pnp_dbg(&dev->dev, " mem %d disabled\n", idx);
goto __add;
}
res->start = rule->min;
res->end = res->start + rule->size - 1;
while (!pnp_check_mem(dev, res)) {
res->start += rule->align;
res->end = res->start + rule->size - 1;
if (res->start > rule->max || !rule->align) {
pnp_dbg(&dev->dev, " couldn't assign mem %d "
"(min %#llx max %#llx)\n", idx,
(unsigned long long) rule->min,
(unsigned long long) rule->max);
return -EBUSY;
}
}
__add:
pnp_add_mem_resource(dev, res->start, res->end, res->flags);
return 0;
}
static int pnp_assign_irq(struct pnp_dev *dev, struct pnp_irq *rule, int idx)
{
struct resource *res, local_res;
int i;
/* IRQ priority: this table is good for i386 */
static unsigned short xtab[16] = {
5, 10, 11, 12, 9, 14, 15, 7, 3, 4, 13, 0, 1, 6, 8, 2
};
res = pnp_find_resource(dev, rule->flags, IORESOURCE_IRQ, idx);
if (res) {
pnp_dbg(&dev->dev, " irq %d already set to %d flags %#lx\n",
idx, (int) res->start, res->flags);
return 0;
}
res = &local_res;
res->flags = rule->flags | IORESOURCE_AUTO;
res->start = -1;
res->end = -1;
if (bitmap_empty(rule->map.bits, PNP_IRQ_NR)) {
res->flags |= IORESOURCE_DISABLED;
pnp_dbg(&dev->dev, " irq %d disabled\n", idx);
goto __add;
}
/* TBD: need check for >16 IRQ */
res->start = find_next_bit(rule->map.bits, PNP_IRQ_NR, 16);
if (res->start < PNP_IRQ_NR) {
res->end = res->start;
goto __add;
}
for (i = 0; i < 16; i++) {
if (test_bit(xtab[i], rule->map.bits)) {
res->start = res->end = xtab[i];
if (pnp_check_irq(dev, res))
goto __add;
}
}
if (rule->flags & IORESOURCE_IRQ_OPTIONAL) {
res->start = -1;
res->end = -1;
res->flags |= IORESOURCE_DISABLED;
pnp_dbg(&dev->dev, " irq %d disabled (optional)\n", idx);
goto __add;
}
pnp_dbg(&dev->dev, " couldn't assign irq %d\n", idx);
return -EBUSY;
__add:
pnp_add_irq_resource(dev, res->start, res->flags);
return 0;
}
#ifdef CONFIG_ISA_DMA_API
static int pnp_assign_dma(struct pnp_dev *dev, struct pnp_dma *rule, int idx)
{
struct resource *res, local_res;
int i;
/* DMA priority: this table is good for i386 */
static unsigned short xtab[8] = {
1, 3, 5, 6, 7, 0, 2, 4
};
res = pnp_find_resource(dev, rule->flags, IORESOURCE_DMA, idx);
if (res) {
pnp_dbg(&dev->dev, " dma %d already set to %d flags %#lx\n",
idx, (int) res->start, res->flags);
return 0;
}
res = &local_res;
res->flags = rule->flags | IORESOURCE_AUTO;
res->start = -1;
res->end = -1;
if (!rule->map) {
res->flags |= IORESOURCE_DISABLED;
pnp_dbg(&dev->dev, " dma %d disabled\n", idx);
goto __add;
}
for (i = 0; i < 8; i++) {
if (rule->map & (1 << xtab[i])) {
res->start = res->end = xtab[i];
if (pnp_check_dma(dev, res))
goto __add;
}
}
pnp_dbg(&dev->dev, " couldn't assign dma %d\n", idx);
return -EBUSY;
__add:
pnp_add_dma_resource(dev, res->start, res->flags);
return 0;
}
#endif /* CONFIG_ISA_DMA_API */
void pnp_init_resources(struct pnp_dev *dev)
{
pnp_free_resources(dev);
}
static void pnp_clean_resource_table(struct pnp_dev *dev)
{
struct pnp_resource *pnp_res, *tmp;
list_for_each_entry_safe(pnp_res, tmp, &dev->resources, list) {
if (pnp_res->res.flags & IORESOURCE_AUTO)
pnp_free_resource(pnp_res);
}
}
/**
* pnp_assign_resources - assigns resources to the device based on the specified dependent number
* @dev: pointer to the desired device
* @set: the dependent function number
*/
static int pnp_assign_resources(struct pnp_dev *dev, int set)
{
struct pnp_option *option;
int nport = 0, nmem = 0, nirq = 0;
int ndma __maybe_unused = 0;
int ret = 0;
pnp_dbg(&dev->dev, "pnp_assign_resources, try dependent set %d\n", set);
mutex_lock(&pnp_res_mutex);
pnp_clean_resource_table(dev);
list_for_each_entry(option, &dev->options, list) {
if (pnp_option_is_dependent(option) &&
pnp_option_set(option) != set)
continue;
switch (option->type) {
case IORESOURCE_IO:
ret = pnp_assign_port(dev, &option->u.port, nport++);
break;
case IORESOURCE_MEM:
ret = pnp_assign_mem(dev, &option->u.mem, nmem++);
break;
case IORESOURCE_IRQ:
ret = pnp_assign_irq(dev, &option->u.irq, nirq++);
break;
#ifdef CONFIG_ISA_DMA_API
case IORESOURCE_DMA:
ret = pnp_assign_dma(dev, &option->u.dma, ndma++);
break;
#endif
default:
ret = -EINVAL;
break;
}
if (ret < 0)
break;
}
mutex_unlock(&pnp_res_mutex);
if (ret < 0) {
pnp_dbg(&dev->dev, "pnp_assign_resources failed (%d)\n", ret);
pnp_clean_resource_table(dev);
} else
dbg_pnp_show_resources(dev, "pnp_assign_resources succeeded");
return ret;
}
/**
* pnp_auto_config_dev - automatically assigns resources to a device
* @dev: pointer to the desired device
*/
int pnp_auto_config_dev(struct pnp_dev *dev)
{
int i, ret;
if (!pnp_can_configure(dev)) {
pnp_dbg(&dev->dev, "configuration not supported\n");
return -ENODEV;
}
ret = pnp_assign_resources(dev, 0);
if (ret == 0)
return 0;
for (i = 1; i < dev->num_dependent_sets; i++) {
ret = pnp_assign_resources(dev, i);
if (ret == 0)
return 0;
}
dev_err(&dev->dev, "unable to assign resources\n");
return ret;
}
/**
* pnp_start_dev - low-level start of the PnP device
* @dev: pointer to the desired device
*
* assumes that resources have already been allocated
*/
int pnp_start_dev(struct pnp_dev *dev)
{
if (!pnp_can_write(dev)) {
pnp_dbg(&dev->dev, "activation not supported\n");
return -EINVAL;
}
dbg_pnp_show_resources(dev, "pnp_start_dev");
if (dev->protocol->set(dev) < 0) {
dev_err(&dev->dev, "activation failed\n");
return -EIO;
}
dev_info(&dev->dev, "activated\n");
return 0;
}
/**
* pnp_stop_dev - low-level disable of the PnP device
* @dev: pointer to the desired device
*
* does not free resources
*/
int pnp_stop_dev(struct pnp_dev *dev)
{
if (!pnp_can_disable(dev)) {
pnp_dbg(&dev->dev, "disabling not supported\n");
return -EINVAL;
}
if (dev->protocol->disable(dev) < 0) {
dev_err(&dev->dev, "disable failed\n");
return -EIO;
}
dev_info(&dev->dev, "disabled\n");
return 0;
}
/**
* pnp_activate_dev - activates a PnP device for use
* @dev: pointer to the desired device
*
* does not validate or set resources so be careful.
*/
int pnp_activate_dev(struct pnp_dev *dev)
{
int error;
if (dev->active)
return 0;
/* ensure resources are allocated */
if (pnp_auto_config_dev(dev))
return -EBUSY;
error = pnp_start_dev(dev);
if (error)
return error;
dev->active = 1;
return 0;
}
/**
* pnp_disable_dev - disables device
* @dev: pointer to the desired device
*
* inform the correct pnp protocol so that resources can be used by other devices
*/
int pnp_disable_dev(struct pnp_dev *dev)
{
int error;
if (!dev->active)
return 0;
error = pnp_stop_dev(dev);
if (error)
return error;
dev->active = 0;
/* release the resources so that other devices can use them */
mutex_lock(&pnp_res_mutex);
pnp_clean_resource_table(dev);
mutex_unlock(&pnp_res_mutex);
return 0;
}
EXPORT_SYMBOL(pnp_start_dev);
EXPORT_SYMBOL(pnp_stop_dev);
EXPORT_SYMBOL(pnp_activate_dev);
EXPORT_SYMBOL(pnp_disable_dev);
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