PCI/MSI: Reorder functions in msi.c

There is no way to navigate msi.c without banging the head against the wall
every now and then because MSI and MSI-X specific functions are
intermingled and the code flow is completely non-obvious.

Reorder everthing so common helpers, MSI and MSI-X specific functions are
grouped together.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20221111122015.459089736@linutronix.de
This commit is contained in:
Ahmed S. Darwish 2022-11-11 14:55:06 +01:00 committed by Thomas Gleixner
parent 88614075a9
commit 12910ffd18

View file

@ -16,6 +16,97 @@
int pci_msi_enable = 1;
int pci_msi_ignore_mask;
/**
* pci_msi_supported - check whether MSI may be enabled on a device
* @dev: pointer to the pci_dev data structure of MSI device function
* @nvec: how many MSIs have been requested?
*
* Look at global flags, the device itself, and its parent buses
* to determine if MSI/-X are supported for the device. If MSI/-X is
* supported return 1, else return 0.
**/
static int pci_msi_supported(struct pci_dev *dev, int nvec)
{
struct pci_bus *bus;
/* MSI must be globally enabled and supported by the device */
if (!pci_msi_enable)
return 0;
if (!dev || dev->no_msi)
return 0;
/*
* You can't ask to have 0 or less MSIs configured.
* a) it's stupid ..
* b) the list manipulation code assumes nvec >= 1.
*/
if (nvec < 1)
return 0;
/*
* Any bridge which does NOT route MSI transactions from its
* secondary bus to its primary bus must set NO_MSI flag on
* the secondary pci_bus.
*
* The NO_MSI flag can either be set directly by:
* - arch-specific PCI host bus controller drivers (deprecated)
* - quirks for specific PCI bridges
*
* or indirectly by platform-specific PCI host bridge drivers by
* advertising the 'msi_domain' property, which results in
* the NO_MSI flag when no MSI domain is found for this bridge
* at probe time.
*/
for (bus = dev->bus; bus; bus = bus->parent)
if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
return 0;
return 1;
}
static void pcim_msi_release(void *pcidev)
{
struct pci_dev *dev = pcidev;
dev->is_msi_managed = false;
pci_free_irq_vectors(dev);
}
/*
* Needs to be separate from pcim_release to prevent an ordering problem
* vs. msi_device_data_release() in the MSI core code.
*/
static int pcim_setup_msi_release(struct pci_dev *dev)
{
int ret;
if (!pci_is_managed(dev) || dev->is_msi_managed)
return 0;
ret = devm_add_action(&dev->dev, pcim_msi_release, dev);
if (!ret)
dev->is_msi_managed = true;
return ret;
}
/*
* Ordering vs. devres: msi device data has to be installed first so that
* pcim_msi_release() is invoked before it on device release.
*/
static int pci_setup_msi_context(struct pci_dev *dev)
{
int ret = msi_setup_device_data(&dev->dev);
if (!ret)
ret = pcim_setup_msi_release(dev);
return ret;
}
/*
* Helper functions for mask/unmask and MSI message handling
*/
void pci_msi_update_mask(struct msi_desc *desc, u32 clear, u32 set)
{
raw_spinlock_t *lock = &to_pci_dev(desc->dev)->msi_lock;
@ -163,15 +254,8 @@ void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg)
}
EXPORT_SYMBOL_GPL(pci_write_msi_msg);
void pci_free_msi_irqs(struct pci_dev *dev)
{
pci_msi_teardown_msi_irqs(dev);
if (dev->msix_base) {
iounmap(dev->msix_base);
dev->msix_base = NULL;
}
}
/* PCI/MSI specific functionality */
static void pci_intx_for_msi(struct pci_dev *dev, int enable)
{
@ -190,111 +274,6 @@ static void pci_msi_set_enable(struct pci_dev *dev, int enable)
pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, control);
}
/*
* Architecture override returns true when the PCI MSI message should be
* written by the generic restore function.
*/
bool __weak arch_restore_msi_irqs(struct pci_dev *dev)
{
return true;
}
void __pci_restore_msi_state(struct pci_dev *dev)
{
struct msi_desc *entry;
u16 control;
if (!dev->msi_enabled)
return;
entry = irq_get_msi_desc(dev->irq);
pci_intx_for_msi(dev, 0);
pci_msi_set_enable(dev, 0);
if (arch_restore_msi_irqs(dev))
__pci_write_msi_msg(entry, &entry->msg);
pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
pci_msi_update_mask(entry, 0, 0);
control &= ~PCI_MSI_FLAGS_QSIZE;
control |= (entry->pci.msi_attrib.multiple << 4) | PCI_MSI_FLAGS_ENABLE;
pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, control);
}
static void pci_msix_clear_and_set_ctrl(struct pci_dev *dev, u16 clear, u16 set)
{
u16 ctrl;
pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &ctrl);
ctrl &= ~clear;
ctrl |= set;
pci_write_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, ctrl);
}
void __pci_restore_msix_state(struct pci_dev *dev)
{
struct msi_desc *entry;
bool write_msg;
if (!dev->msix_enabled)
return;
/* route the table */
pci_intx_for_msi(dev, 0);
pci_msix_clear_and_set_ctrl(dev, 0,
PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL);
write_msg = arch_restore_msi_irqs(dev);
msi_lock_descs(&dev->dev);
msi_for_each_desc(entry, &dev->dev, MSI_DESC_ALL) {
if (write_msg)
__pci_write_msi_msg(entry, &entry->msg);
pci_msix_write_vector_ctrl(entry, entry->pci.msix_ctrl);
}
msi_unlock_descs(&dev->dev);
pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
}
static void pcim_msi_release(void *pcidev)
{
struct pci_dev *dev = pcidev;
dev->is_msi_managed = false;
pci_free_irq_vectors(dev);
}
/*
* Needs to be separate from pcim_release to prevent an ordering problem
* vs. msi_device_data_release() in the MSI core code.
*/
static int pcim_setup_msi_release(struct pci_dev *dev)
{
int ret;
if (!pci_is_managed(dev) || dev->is_msi_managed)
return 0;
ret = devm_add_action(&dev->dev, pcim_msi_release, dev);
if (!ret)
dev->is_msi_managed = true;
return ret;
}
/*
* Ordering vs. devres: msi device data has to be installed first so that
* pcim_msi_release() is invoked before it on device release.
*/
static int pci_setup_msi_context(struct pci_dev *dev)
{
int ret = msi_setup_device_data(&dev->dev);
if (!ret)
ret = pcim_setup_msi_release(dev);
return ret;
}
static int msi_setup_msi_desc(struct pci_dev *dev, int nvec,
struct irq_affinity_desc *masks)
{
@ -415,6 +394,149 @@ static int msi_capability_init(struct pci_dev *dev, int nvec,
return ret;
}
int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
struct irq_affinity *affd)
{
int nvec;
int rc;
if (!pci_msi_supported(dev, minvec) || dev->current_state != PCI_D0)
return -EINVAL;
/* Check whether driver already requested MSI-X IRQs */
if (dev->msix_enabled) {
pci_info(dev, "can't enable MSI (MSI-X already enabled)\n");
return -EINVAL;
}
if (maxvec < minvec)
return -ERANGE;
if (WARN_ON_ONCE(dev->msi_enabled))
return -EINVAL;
nvec = pci_msi_vec_count(dev);
if (nvec < 0)
return nvec;
if (nvec < minvec)
return -ENOSPC;
if (nvec > maxvec)
nvec = maxvec;
rc = pci_setup_msi_context(dev);
if (rc)
return rc;
for (;;) {
if (affd) {
nvec = irq_calc_affinity_vectors(minvec, nvec, affd);
if (nvec < minvec)
return -ENOSPC;
}
rc = msi_capability_init(dev, nvec, affd);
if (rc == 0)
return nvec;
if (rc < 0)
return rc;
if (rc < minvec)
return -ENOSPC;
nvec = rc;
}
}
/**
* pci_msi_vec_count - Return the number of MSI vectors a device can send
* @dev: device to report about
*
* This function returns the number of MSI vectors a device requested via
* Multiple Message Capable register. It returns a negative errno if the
* device is not capable sending MSI interrupts. Otherwise, the call succeeds
* and returns a power of two, up to a maximum of 2^5 (32), according to the
* MSI specification.
**/
int pci_msi_vec_count(struct pci_dev *dev)
{
int ret;
u16 msgctl;
if (!dev->msi_cap)
return -EINVAL;
pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &msgctl);
ret = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
return ret;
}
EXPORT_SYMBOL(pci_msi_vec_count);
/*
* Architecture override returns true when the PCI MSI message should be
* written by the generic restore function.
*/
bool __weak arch_restore_msi_irqs(struct pci_dev *dev)
{
return true;
}
void __pci_restore_msi_state(struct pci_dev *dev)
{
struct msi_desc *entry;
u16 control;
if (!dev->msi_enabled)
return;
entry = irq_get_msi_desc(dev->irq);
pci_intx_for_msi(dev, 0);
pci_msi_set_enable(dev, 0);
if (arch_restore_msi_irqs(dev))
__pci_write_msi_msg(entry, &entry->msg);
pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
pci_msi_update_mask(entry, 0, 0);
control &= ~PCI_MSI_FLAGS_QSIZE;
control |= (entry->pci.msi_attrib.multiple << 4) | PCI_MSI_FLAGS_ENABLE;
pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, control);
}
void pci_msi_shutdown(struct pci_dev *dev)
{
struct msi_desc *desc;
if (!pci_msi_enable || !dev || !dev->msi_enabled)
return;
pci_msi_set_enable(dev, 0);
pci_intx_for_msi(dev, 1);
dev->msi_enabled = 0;
/* Return the device with MSI unmasked as initial states */
desc = msi_first_desc(&dev->dev, MSI_DESC_ALL);
if (!WARN_ON_ONCE(!desc))
pci_msi_unmask(desc, msi_multi_mask(desc));
/* Restore dev->irq to its default pin-assertion IRQ */
dev->irq = desc->pci.msi_attrib.default_irq;
pcibios_alloc_irq(dev);
}
/* PCI/MSI-X specific functionality */
static void pci_msix_clear_and_set_ctrl(struct pci_dev *dev, u16 clear, u16 set)
{
u16 ctrl;
pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &ctrl);
ctrl &= ~clear;
ctrl |= set;
pci_write_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, ctrl);
}
static void __iomem *msix_map_region(struct pci_dev *dev,
unsigned int nr_entries)
{
@ -599,101 +721,6 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries,
return ret;
}
/**
* pci_msi_supported - check whether MSI may be enabled on a device
* @dev: pointer to the pci_dev data structure of MSI device function
* @nvec: how many MSIs have been requested?
*
* Look at global flags, the device itself, and its parent buses
* to determine if MSI/-X are supported for the device. If MSI/-X is
* supported return 1, else return 0.
**/
static int pci_msi_supported(struct pci_dev *dev, int nvec)
{
struct pci_bus *bus;
/* MSI must be globally enabled and supported by the device */
if (!pci_msi_enable)
return 0;
if (!dev || dev->no_msi)
return 0;
/*
* You can't ask to have 0 or less MSIs configured.
* a) it's stupid ..
* b) the list manipulation code assumes nvec >= 1.
*/
if (nvec < 1)
return 0;
/*
* Any bridge which does NOT route MSI transactions from its
* secondary bus to its primary bus must set NO_MSI flag on
* the secondary pci_bus.
*
* The NO_MSI flag can either be set directly by:
* - arch-specific PCI host bus controller drivers (deprecated)
* - quirks for specific PCI bridges
*
* or indirectly by platform-specific PCI host bridge drivers by
* advertising the 'msi_domain' property, which results in
* the NO_MSI flag when no MSI domain is found for this bridge
* at probe time.
*/
for (bus = dev->bus; bus; bus = bus->parent)
if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
return 0;
return 1;
}
/**
* pci_msi_vec_count - Return the number of MSI vectors a device can send
* @dev: device to report about
*
* This function returns the number of MSI vectors a device requested via
* Multiple Message Capable register. It returns a negative errno if the
* device is not capable sending MSI interrupts. Otherwise, the call succeeds
* and returns a power of two, up to a maximum of 2^5 (32), according to the
* MSI specification.
**/
int pci_msi_vec_count(struct pci_dev *dev)
{
int ret;
u16 msgctl;
if (!dev->msi_cap)
return -EINVAL;
pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &msgctl);
ret = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
return ret;
}
EXPORT_SYMBOL(pci_msi_vec_count);
void pci_msi_shutdown(struct pci_dev *dev)
{
struct msi_desc *desc;
if (!pci_msi_enable || !dev || !dev->msi_enabled)
return;
pci_msi_set_enable(dev, 0);
pci_intx_for_msi(dev, 1);
dev->msi_enabled = 0;
/* Return the device with MSI unmasked as initial states */
desc = msi_first_desc(&dev->dev, MSI_DESC_ALL);
if (!WARN_ON_ONCE(!desc))
pci_msi_unmask(desc, msi_multi_mask(desc));
/* Restore dev->irq to its default pin-assertion IRQ */
dev->irq = desc->pci.msi_attrib.default_irq;
pcibios_alloc_irq(dev);
}
static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries,
int nvec, struct irq_affinity *affd, int flags)
{
@ -729,82 +756,6 @@ static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries,
return msix_capability_init(dev, entries, nvec, affd);
}
void pci_msix_shutdown(struct pci_dev *dev)
{
struct msi_desc *desc;
if (!pci_msi_enable || !dev || !dev->msix_enabled)
return;
if (pci_dev_is_disconnected(dev)) {
dev->msix_enabled = 0;
return;
}
/* Return the device with MSI-X masked as initial states */
msi_for_each_desc(desc, &dev->dev, MSI_DESC_ALL)
pci_msix_mask(desc);
pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
pci_intx_for_msi(dev, 1);
dev->msix_enabled = 0;
pcibios_alloc_irq(dev);
}
int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
struct irq_affinity *affd)
{
int nvec;
int rc;
if (!pci_msi_supported(dev, minvec) || dev->current_state != PCI_D0)
return -EINVAL;
/* Check whether driver already requested MSI-X IRQs */
if (dev->msix_enabled) {
pci_info(dev, "can't enable MSI (MSI-X already enabled)\n");
return -EINVAL;
}
if (maxvec < minvec)
return -ERANGE;
if (WARN_ON_ONCE(dev->msi_enabled))
return -EINVAL;
nvec = pci_msi_vec_count(dev);
if (nvec < 0)
return nvec;
if (nvec < minvec)
return -ENOSPC;
if (nvec > maxvec)
nvec = maxvec;
rc = pci_setup_msi_context(dev);
if (rc)
return rc;
for (;;) {
if (affd) {
nvec = irq_calc_affinity_vectors(minvec, nvec, affd);
if (nvec < minvec)
return -ENOSPC;
}
rc = msi_capability_init(dev, nvec, affd);
if (rc == 0)
return nvec;
if (rc < 0)
return rc;
if (rc < minvec)
return -ENOSPC;
nvec = rc;
}
}
int __pci_enable_msix_range(struct pci_dev *dev,
struct msix_entry *entries, int minvec,
int maxvec, struct irq_affinity *affd,
@ -847,6 +798,68 @@ int __pci_enable_msix_range(struct pci_dev *dev,
}
}
void __pci_restore_msix_state(struct pci_dev *dev)
{
struct msi_desc *entry;
bool write_msg;
if (!dev->msix_enabled)
return;
/* route the table */
pci_intx_for_msi(dev, 0);
pci_msix_clear_and_set_ctrl(dev, 0,
PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL);
write_msg = arch_restore_msi_irqs(dev);
msi_lock_descs(&dev->dev);
msi_for_each_desc(entry, &dev->dev, MSI_DESC_ALL) {
if (write_msg)
__pci_write_msi_msg(entry, &entry->msg);
pci_msix_write_vector_ctrl(entry, entry->pci.msix_ctrl);
}
msi_unlock_descs(&dev->dev);
pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
}
void pci_msix_shutdown(struct pci_dev *dev)
{
struct msi_desc *desc;
if (!pci_msi_enable || !dev || !dev->msix_enabled)
return;
if (pci_dev_is_disconnected(dev)) {
dev->msix_enabled = 0;
return;
}
/* Return the device with MSI-X masked as initial states */
msi_for_each_desc(desc, &dev->dev, MSI_DESC_ALL)
pci_msix_mask(desc);
pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
pci_intx_for_msi(dev, 1);
dev->msix_enabled = 0;
pcibios_alloc_irq(dev);
}
/* Common interfaces */
void pci_free_msi_irqs(struct pci_dev *dev)
{
pci_msi_teardown_msi_irqs(dev);
if (dev->msix_base) {
iounmap(dev->msix_base);
dev->msix_base = NULL;
}
}
/* Misc. infrastructure */
struct pci_dev *msi_desc_to_pci_dev(struct msi_desc *desc)
{
return to_pci_dev(desc->dev);