// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/ntb.h>
#include <linux/msi.h>
#include <linux/pci.h>
struct ntb_msi {
u64 base_addr;
u64 end_addr;
void (*desc_changed)(void *ctx);
u32 __iomem *peer_mws[];
};
/**
* ntb_msi_init() - Initialize the MSI context
* @ntb: NTB device context
*
* This function must be called before any other ntb_msi function.
* It initializes the context for MSI operations and maps
* the peer memory windows.
*
* This function reserves the last N outbound memory windows (where N
* is the number of peers).
*
* Return: Zero on success, otherwise a negative error number.
*/
int ntb_msi_init(struct ntb_dev *ntb,
void (*desc_changed)(void *ctx))
{
phys_addr_t mw_phys_addr;
resource_size_t mw_size;
size_t struct_size;
int peer_widx;
int peers;
int ret;
int i;
peers = ntb_peer_port_count(ntb);
if (peers <= 0)
return -EINVAL;
struct_size = sizeof(*ntb->msi) + sizeof(*ntb->msi->peer_mws) * peers;
ntb->msi = devm_kzalloc(&ntb->dev, struct_size, GFP_KERNEL);
if (!ntb->msi)
return -ENOMEM;
ntb->msi->desc_changed = desc_changed;
for (i = 0; i < peers; i++) {
peer_widx = ntb_peer_mw_count(ntb) - 1 - i;
ret = ntb_peer_mw_get_addr(ntb, peer_widx, &mw_phys_addr,
&mw_size);
if (ret)
goto unroll;
ntb->msi->peer_mws[i] = devm_ioremap(&ntb->dev, mw_phys_addr,
mw_size);
if (!ntb->msi->peer_mws[i]) {
ret = -EFAULT;
goto unroll;
}
}
return 0;
unroll:
for (i = 0; i < peers; i++)
if (ntb->msi->peer_mws[i])
devm_iounmap(&ntb->dev, ntb->msi->peer_mws[i]);
devm_kfree(&ntb->dev, ntb->msi);
ntb->msi = NULL;
return ret;
}
EXPORT_SYMBOL(ntb_msi_init);
/**
* ntb_msi_setup_mws() - Initialize the MSI inbound memory windows
* @ntb: NTB device context
*
* This function sets up the required inbound memory windows. It should be
* called from a work function after a link up event.
*
* Over the entire network, this function will reserves the last N
* inbound memory windows for each peer (where N is the number of peers).
*
* ntb_msi_init() must be called before this function.
*
* Return: Zero on success, otherwise a negative error number.
*/
int ntb_msi_setup_mws(struct ntb_dev *ntb)
{
struct msi_desc *desc;
u64 addr;
int peer, peer_widx;
resource_size_t addr_align, size_align, size_max;
resource_size_t mw_size = SZ_32K;
resource_size_t mw_min_size = mw_size;
int i;
int ret;
if (!ntb->msi)
return -EINVAL;
msi_lock_descs(&ntb->pdev->dev);
desc = msi_first_desc(&ntb->pdev->dev, MSI_DESC_ASSOCIATED);
addr = desc->msg.address_lo + ((uint64_t)desc->msg.address_hi << 32);
msi_unlock_descs(&ntb->pdev->dev);
for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
if (peer_widx < 0)
return peer_widx;
ret = ntb_mw_get_align(ntb, peer, peer_widx, &addr_align,
NULL, NULL);
if (ret)
return ret;
addr &= ~(addr_align - 1);
}
for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
if (peer_widx < 0) {
ret = peer_widx;
goto error_out;
}
ret = ntb_mw_get_align(ntb, peer, peer_widx, NULL,
&size_align, &size_max);
if (ret)
goto error_out;
mw_size = round_up(mw_size, size_align);
mw_size = max(mw_size, size_max);
if (mw_size < mw_min_size)
mw_min_size = mw_size;
ret = ntb_mw_set_trans(ntb, peer, peer_widx,
addr, mw_size);
if (ret)
goto error_out;
}
ntb->msi->base_addr = addr;
ntb->msi->end_addr = addr + mw_min_size;
return 0;
error_out:
for (i = 0; i < peer; i++) {
peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
if (peer_widx < 0)
continue;
ntb_mw_clear_trans(ntb, i, peer_widx);
}
return ret;
}
EXPORT_SYMBOL(ntb_msi_setup_mws);
/**
* ntb_msi_clear_mws() - Clear all inbound memory windows
* @ntb: NTB device context
*
* This function tears down the resources used by ntb_msi_setup_mws().
*/
void ntb_msi_clear_mws(struct ntb_dev *ntb)
{
int peer;
int peer_widx;
for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
if (peer_widx < 0)
continue;
ntb_mw_clear_trans(ntb, peer, peer_widx);
}
}
EXPORT_SYMBOL(ntb_msi_clear_mws);
struct ntb_msi_devres {
struct ntb_dev *ntb;
struct msi_desc *entry;
struct ntb_msi_desc *msi_desc;
};
static int ntb_msi_set_desc(struct ntb_dev *ntb, struct msi_desc *entry,
struct ntb_msi_desc *msi_desc)
{
u64 addr;
addr = entry->msg.address_lo +
((uint64_t)entry->msg.address_hi << 32);
if (addr < ntb->msi->base_addr || addr >= ntb->msi->end_addr) {
dev_warn_once(&ntb->dev,
"IRQ %d: MSI Address not within the memory window (%llx, [%llx %llx])\n",
entry->irq, addr, ntb->msi->base_addr,
ntb->msi->end_addr);
return -EFAULT;
}
msi_desc->addr_offset = addr - ntb->msi->base_addr;
msi_desc->data = entry->msg.data;
return 0;
}
static void ntb_msi_write_msg(struct msi_desc *entry, void *data)
{
struct ntb_msi_devres *dr = data;
WARN_ON(ntb_msi_set_desc(dr->ntb, entry, dr->msi_desc));
if (dr->ntb->msi->desc_changed)
dr->ntb->msi->desc_changed(dr->ntb->ctx);
}
static void ntbm_msi_callback_release(struct device *dev, void *res)
{
struct ntb_msi_devres *dr = res;
dr->entry->write_msi_msg = NULL;
dr->entry->write_msi_msg_data = NULL;
}
static int ntbm_msi_setup_callback(struct ntb_dev *ntb, struct msi_desc *entry,
struct ntb_msi_desc *msi_desc)
{
struct ntb_msi_devres *dr;
dr = devres_alloc(ntbm_msi_callback_release,
sizeof(struct ntb_msi_devres), GFP_KERNEL);
if (!dr)
return -ENOMEM;
dr->ntb = ntb;
dr->entry = entry;
dr->msi_desc = msi_desc;
devres_add(&ntb->dev, dr);
dr->entry->write_msi_msg = ntb_msi_write_msg;
dr->entry->write_msi_msg_data = dr;
return 0;
}
/**
* ntbm_msi_request_threaded_irq() - allocate an MSI interrupt
* @ntb: NTB device context
* @handler: Function to be called when the IRQ occurs
* @thread_fn: Function to be called in a threaded interrupt context. NULL
* for clients which handle everything in @handler
* @name: An ascii name for the claiming device, dev_name(dev) if NULL
* @dev_id: A cookie passed back to the handler function
* @msi_desc: MSI descriptor data which triggers the interrupt
*
* This function assigns an interrupt handler to an unused
* MSI interrupt and returns the descriptor used to trigger
* it. The descriptor can then be sent to a peer to trigger
* the interrupt.
*
* The interrupt resource is managed with devres so it will
* be automatically freed when the NTB device is torn down.
*
* If an IRQ allocated with this function needs to be freed
* separately, ntbm_free_irq() must be used.
*
* Return: IRQ number assigned on success, otherwise a negative error number.
*/
int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb, irq_handler_t handler,
irq_handler_t thread_fn,
const char *name, void *dev_id,
struct ntb_msi_desc *msi_desc)
{
struct device *dev = &ntb->pdev->dev;
struct msi_desc *entry;
int ret;
if (!ntb->msi)
return -EINVAL;
msi_lock_descs(dev);
msi_for_each_desc(entry, dev, MSI_DESC_ASSOCIATED) {
if (irq_has_action(entry->irq))
continue;
ret = devm_request_threaded_irq(&ntb->dev, entry->irq, handler,
thread_fn, 0, name, dev_id);
if (ret)
continue;
if (ntb_msi_set_desc(ntb, entry, msi_desc)) {
devm_free_irq(&ntb->dev, entry->irq, dev_id);
continue;
}
ret = ntbm_msi_setup_callback(ntb, entry, msi_desc);
if (ret) {
devm_free_irq(&ntb->dev, entry->irq, dev_id);
goto unlock;
}
ret = entry->irq;
goto unlock;
}
ret = -ENODEV;
unlock:
msi_unlock_descs(dev);
return ret;
}
EXPORT_SYMBOL(ntbm_msi_request_threaded_irq);
static int ntbm_msi_callback_match(struct device *dev, void *res, void *data)
{
struct ntb_dev *ntb = dev_ntb(dev);
struct ntb_msi_devres *dr = res;
return dr->ntb == ntb && dr->entry == data;
}
/**
* ntbm_msi_free_irq() - free an interrupt
* @ntb: NTB device context
* @irq: Interrupt line to free
* @dev_id: Device identity to free
*
* This function should be used to manually free IRQs allocated with
* ntbm_request_[threaded_]irq().
*/
void ntbm_msi_free_irq(struct ntb_dev *ntb, unsigned int irq, void *dev_id)
{
struct msi_desc *entry = irq_get_msi_desc(irq);
entry->write_msi_msg = NULL;
entry->write_msi_msg_data = NULL;
WARN_ON(devres_destroy(&ntb->dev, ntbm_msi_callback_release,
ntbm_msi_callback_match, entry));
devm_free_irq(&ntb->dev, irq, dev_id);
}
EXPORT_SYMBOL(ntbm_msi_free_irq);
/**
* ntb_msi_peer_trigger() - Trigger an interrupt handler on a peer
* @ntb: NTB device context
* @peer: Peer index
* @desc: MSI descriptor data which triggers the interrupt
*
* This function triggers an interrupt on a peer. It requires
* the descriptor structure to have been passed from that peer
* by some other means.
*
* Return: Zero on success, otherwise a negative error number.
*/
int ntb_msi_peer_trigger(struct ntb_dev *ntb, int peer,
struct ntb_msi_desc *desc)
{
int idx;
if (!ntb->msi)
return -EINVAL;
idx = desc->addr_offset / sizeof(*ntb->msi->peer_mws[peer]);
iowrite32(desc->data, &ntb->msi->peer_mws[peer][idx]);
return 0;
}
EXPORT_SYMBOL(ntb_msi_peer_trigger);
/**
* ntb_msi_peer_addr() - Get the DMA address to trigger a peer's MSI interrupt
* @ntb: NTB device context
* @peer: Peer index
* @desc: MSI descriptor data which triggers the interrupt
* @msi_addr: Physical address to trigger the interrupt
*
* This function allows using DMA engines to trigger an interrupt
* (for example, trigger an interrupt to process the data after
* sending it). To trigger the interrupt, write @desc.data to the address
* returned in @msi_addr
*
* Return: Zero on success, otherwise a negative error number.
*/
int ntb_msi_peer_addr(struct ntb_dev *ntb, int peer,
struct ntb_msi_desc *desc,
phys_addr_t *msi_addr)
{
int peer_widx = ntb_peer_mw_count(ntb) - 1 - peer;
phys_addr_t mw_phys_addr;
int ret;
ret = ntb_peer_mw_get_addr(ntb, peer_widx, &mw_phys_addr, NULL);
if (ret)
return ret;
if (msi_addr)
*msi_addr = mw_phys_addr + desc->addr_offset;
return 0;
}
EXPORT_SYMBOL(ntb_msi_peer_addr);