PCI IRQs: Swizzle PCI IRQs for PCI bridges
The PCI Specification states that devices that implement a bridge and a secondary bus must swizzle (rotate) the interrupt pins according to the table below: Child Dev # Child PIN Parent PIN 0,4,8,12... A/B/C/D A/B/C/D 1,5,9,13... A/B/C/D B/C/D/A 2,6,10,14.. A/B/C/D C/D/A/B 3,7,11,15.. A/B/C/D D/A/B/C Which is also described by this equation: PIN_parent = (Pin_child + Dev_child) % 4 When a device is found and its bus number is greater than 0, it is on a bridge and needs to be swizzled. Following the string of parents up to the root bus and swizzling as we go gives us the desired swizzling result. When BIOS_SPEW is defined, it will print out each step of the swizzling process. Change-Id: Icafeadd01983282c86e25f560c831c9482c74e68 Signed-off-by: Martin Roth <gaumless@gmail.com> Reviewed-on: http://review.coreboot.org/5734 Tested-by: build bot (Jenkins) Reviewed-by: Marc Jones <marc.jones@se-eng.com> Reviewed-by: Mike Loptien <mike.loptien@se-eng.com>
This commit is contained in:
Mike Loptien
Martin Roth
parent
433659ad1e
commit
0f5cf5e45b
|
|
@ -12,6 +12,7 @@
|
|||
* (Written by Yinghai Lu <yhlu@tyan.com> for Tyan)
|
||||
* Copyright (C) 2005-2009 coresystems GmbH
|
||||
* (Written by Stefan Reinauer <stepan@coresystems.de> for coresystems GmbH)
|
||||
* Copyright (C) 2014 Sage Electronic Engineering, LLC.
|
||||
*/
|
||||
|
||||
/*
|
||||
|
|
@ -1303,6 +1304,156 @@ unsigned int pci_domain_scan_bus(device_t dev, unsigned int max)
|
|||
return max;
|
||||
}
|
||||
|
||||
/**
|
||||
* Take an INT_PIN number (0, 1 - 4) and convert
|
||||
* it to a string ("NO PIN", "PIN A" - "PIN D")
|
||||
*
|
||||
* @param pin PCI Interrupt Pin number (0, 1 - 4)
|
||||
* @return A string corresponding to the pin number or "Invalid"
|
||||
*/
|
||||
const char *pin_to_str(int pin)
|
||||
{
|
||||
const char *str[5] = {
|
||||
"NO PIN",
|
||||
"PIN A",
|
||||
"PIN B",
|
||||
"PIN C",
|
||||
"PIN D",
|
||||
};
|
||||
|
||||
if (pin >= 0 && pin <= 4)
|
||||
return str[pin];
|
||||
else
|
||||
return "Invalid PIN, not 0 - 4";
|
||||
}
|
||||
|
||||
/**
|
||||
* Get the PCI INT_PIN swizzle for a device defined as:
|
||||
* pin_parent = (pin_child + devn_child) % 4 + 1
|
||||
* where PIN A = 1 ... PIN_D = 4
|
||||
*
|
||||
* Given a PCI device structure 'dev', find the interrupt pin
|
||||
* that will be triggered on its parent bridge device when
|
||||
* generating an interrupt. For example: Device 1:3.2 may
|
||||
* use INT_PIN A but will trigger PIN D on its parent bridge
|
||||
* device. In this case, this function will return 4 (PIN D).
|
||||
*
|
||||
* @param dev A PCI device structure to swizzle interrupt pins for
|
||||
* @param *parent_bdg The PCI device structure for the bridge
|
||||
* device 'dev' is attached to
|
||||
* @return The interrupt pin number (1 - 4) that 'dev' will
|
||||
* trigger when generating an interrupt
|
||||
*/
|
||||
static int swizzle_irq_pins(device_t dev, device_t *parent_bridge)
|
||||
{
|
||||
device_t parent; /* Our current device's parent device */
|
||||
device_t child; /* The child device of the parent */
|
||||
uint8_t parent_bus = 0; /* Parent Bus number */
|
||||
uint16_t parent_devfn = 0; /* Parent Device and Function number */
|
||||
uint16_t child_devfn = 0; /* Child Device and Function number */
|
||||
uint8_t swizzled_pin = 0; /* Pin swizzled across a bridge */
|
||||
|
||||
/* Start with PIN A = 0 ... D = 3 */
|
||||
swizzled_pin = pci_read_config8(dev, PCI_INTERRUPT_PIN) - 1;
|
||||
|
||||
/* While our current device has parent devices */
|
||||
child = dev;
|
||||
for (parent = child->bus->dev; parent; parent = parent->bus->dev) {
|
||||
parent_bus = parent->bus->secondary;
|
||||
parent_devfn = parent->path.pci.devfn;
|
||||
child_devfn = child->path.pci.devfn;
|
||||
|
||||
/* Swizzle the INT_PIN for any bridges not on root bus */
|
||||
swizzled_pin = (PCI_SLOT(child_devfn) + swizzled_pin) % 4;
|
||||
printk(BIOS_SPEW, "\tWith INT_PIN swizzled to %s\n"
|
||||
"\tAttached to bridge device %01X:%02Xh.%02Xh\n",
|
||||
pin_to_str(swizzled_pin + 1), parent_bus,
|
||||
PCI_SLOT(parent_devfn), PCI_FUNC(parent_devfn));
|
||||
|
||||
/* Continue until we find the root bus */
|
||||
if (parent_bus > 0) {
|
||||
/*
|
||||
* We will go on to the next parent so this parent
|
||||
* becomes the child
|
||||
*/
|
||||
child = parent;
|
||||
continue;
|
||||
} else {
|
||||
/*
|
||||
* Found the root bridge device,
|
||||
* fill in the structure and exit
|
||||
*/
|
||||
*parent_bridge = parent;
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
/* End with PIN A = 1 ... D = 4 */
|
||||
return swizzled_pin + 1;
|
||||
}
|
||||
|
||||
/**
|
||||
* Given a device structure 'dev', find its interrupt pin
|
||||
* and its parent bridge 'parent_bdg' device structure.
|
||||
* If it is behind a bridge, it will return the interrupt
|
||||
* pin number (1 - 4) of the parent bridge that the device
|
||||
* interrupt pin has been swizzled to, otherwise it will
|
||||
* return the interrupt pin that is programmed into the
|
||||
* PCI config space of the target device. If 'dev' is
|
||||
* behind a bridge, it will fill in 'parent_bdg' with the
|
||||
* device structure of the bridge it is behind, otherwise
|
||||
* it will copy 'dev' into 'parent_bdg'.
|
||||
*
|
||||
* @param dev A PCI device structure to get interrupt pins for.
|
||||
* @param *parent_bdg The PCI device structure for the bridge
|
||||
* device 'dev' is attached to.
|
||||
* @return The interrupt pin number (1 - 4) that 'dev' will
|
||||
* trigger when generating an interrupt.
|
||||
* Errors: -1 is returned if the device is not enabled
|
||||
* -2 is returned if a parent bridge could not be found.
|
||||
*/
|
||||
int get_pci_irq_pins(device_t dev, device_t *parent_bdg)
|
||||
{
|
||||
uint8_t bus = 0; /* The bus this device is on */
|
||||
uint16_t devfn = 0; /* This device's device and function numbers */
|
||||
uint8_t int_pin = 0; /* Interrupt pin used by the device */
|
||||
uint8_t target_pin = 0; /* Interrupt pin we want to assign an IRQ to */
|
||||
|
||||
/* Make sure this device is enabled */
|
||||
if (!(dev->enabled && (dev->path.type == DEVICE_PATH_PCI)))
|
||||
return -1;
|
||||
|
||||
bus = dev->bus->secondary;
|
||||
devfn = dev->path.pci.devfn;
|
||||
|
||||
/* Get and validate the interrupt pin used. Only 1-4 are allowed */
|
||||
int_pin = pci_read_config8(dev, PCI_INTERRUPT_PIN);
|
||||
if (int_pin < 1 || int_pin > 4)
|
||||
return -1;
|
||||
|
||||
printk(BIOS_SPEW, "PCI IRQ: Found device %01X:%02X.%02X using %s\n",
|
||||
bus, PCI_SLOT(devfn), PCI_FUNC(devfn), pin_to_str(int_pin));
|
||||
|
||||
/* If this device is on a bridge, swizzle its INT_PIN */
|
||||
if (bus) {
|
||||
/* Swizzle its INT_PINs */
|
||||
target_pin = swizzle_irq_pins(dev, parent_bdg);
|
||||
|
||||
/* Make sure the swizzle returned valid structures */
|
||||
if (parent_bdg == NULL) {
|
||||
printk(BIOS_WARNING,
|
||||
"Warning: Could not find parent bridge for this device!\n");
|
||||
return -2;
|
||||
}
|
||||
} else { /* Device is not behind a bridge */
|
||||
target_pin = int_pin; /* Return its own interrupt pin */
|
||||
*parent_bdg = dev; /* Return its own structure */
|
||||
}
|
||||
|
||||
/* Target pin is the interrupt pin we want to assign an IRQ to */
|
||||
return target_pin;
|
||||
}
|
||||
|
||||
#if CONFIG_PC80_SYSTEM
|
||||
/**
|
||||
* Assign IRQ numbers.
|
||||
|
|
|
|||
|
|
@ -82,6 +82,8 @@ void pci_dev_set_subsystem(device_t dev, unsigned vendor, unsigned device);
|
|||
void pci_dev_init(struct device *dev);
|
||||
unsigned int pci_match_simple_dev(device_t dev, pci_devfn_t sdev);
|
||||
|
||||
const char * pin_to_str(int pin);
|
||||
int get_pci_irq_pins(device_t dev, device_t *parent_bdg);
|
||||
void pci_assign_irqs(unsigned bus, unsigned slot,
|
||||
const unsigned char pIntAtoD[4]);
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue