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// SPDX-License-Identifier: GPL-2.0
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdomain.h>
#include <linux/pci-ecam.h>
#include <linux/delay.h>
#include <linux/msi.h>
#include <linux/of_address.h>
#define MSI_MAX 256
#define SMP8759_MUX 0x48
#define SMP8759_TEST_OUT 0x74
#define SMP8759_DOORBELL 0x7c
#define SMP8759_STATUS 0x80
#define SMP8759_ENABLE 0xa0
struct tango_pcie {
DECLARE_BITMAP(used_msi, MSI_MAX);
u64 msi_doorbell;
spinlock_t used_msi_lock;
void __iomem *base;
struct irq_domain *dom;
};
static void tango_msi_isr(struct irq_desc *desc)
{
struct irq_chip *chip = irq_desc_get_chip(desc);
struct tango_pcie *pcie = irq_desc_get_handler_data(desc);
unsigned long status, base, virq, idx, pos = 0;
chained_irq_enter(chip, desc);
spin_lock(&pcie->used_msi_lock);
while ((pos = find_next_bit(pcie->used_msi, MSI_MAX, pos)) < MSI_MAX) {
base = round_down(pos, 32);
status = readl_relaxed(pcie->base + SMP8759_STATUS + base / 8);
for_each_set_bit(idx, &status, 32) {
virq = irq_find_mapping(pcie->dom, base + idx);
generic_handle_irq(virq);
}
pos = base + 32;
}
spin_unlock(&pcie->used_msi_lock);
chained_irq_exit(chip, desc);
}
static void tango_ack(struct irq_data *d)
{
struct tango_pcie *pcie = d->chip_data;
u32 offset = (d->hwirq / 32) * 4;
u32 bit = BIT(d->hwirq % 32);
writel_relaxed(bit, pcie->base + SMP8759_STATUS + offset);
}
static void update_msi_enable(struct irq_data *d, bool unmask)
{
unsigned long flags;
struct tango_pcie *pcie = d->chip_data;
u32 offset = (d->hwirq / 32) * 4;
u32 bit = BIT(d->hwirq % 32);
u32 val;
spin_lock_irqsave(&pcie->used_msi_lock, flags);
val = readl_relaxed(pcie->base + SMP8759_ENABLE + offset);
val = unmask ? val | bit : val & ~bit;
writel_relaxed(val, pcie->base + SMP8759_ENABLE + offset);
spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
}
static void tango_mask(struct irq_data *d)
{
update_msi_enable(d, false);
}
static void tango_unmask(struct irq_data *d)
{
update_msi_enable(d, true);
}
static int tango_set_affinity(struct irq_data *d, const struct cpumask *mask,
bool force)
{
return -EINVAL;
}
static void tango_compose_msi_msg(struct irq_data *d, struct msi_msg *msg)
{
struct tango_pcie *pcie = d->chip_data;
msg->address_lo = lower_32_bits(pcie->msi_doorbell);
msg->address_hi = upper_32_bits(pcie->msi_doorbell);
msg->data = d->hwirq;
}
static struct irq_chip tango_chip = {
.irq_ack = tango_ack,
.irq_mask = tango_mask,
.irq_unmask = tango_unmask,
.irq_set_affinity = tango_set_affinity,
.irq_compose_msi_msg = tango_compose_msi_msg,
};
static void msi_ack(struct irq_data *d)
{
irq_chip_ack_parent(d);
}
static void msi_mask(struct irq_data *d)
{
pci_msi_mask_irq(d);
irq_chip_mask_parent(d);
}
static void msi_unmask(struct irq_data *d)
{
pci_msi_unmask_irq(d);
irq_chip_unmask_parent(d);
}
static struct irq_chip msi_chip = {
.name = "MSI",
.irq_ack = msi_ack,
.irq_mask = msi_mask,
.irq_unmask = msi_unmask,
};
static struct msi_domain_info msi_dom_info = {
.flags = MSI_FLAG_PCI_MSIX
| MSI_FLAG_USE_DEF_DOM_OPS
| MSI_FLAG_USE_DEF_CHIP_OPS,
.chip = &msi_chip,
};
static int tango_irq_domain_alloc(struct irq_domain *dom, unsigned int virq,
unsigned int nr_irqs, void *args)
{
struct tango_pcie *pcie = dom->host_data;
unsigned long flags;
int pos;
spin_lock_irqsave(&pcie->used_msi_lock, flags);
pos = find_first_zero_bit(pcie->used_msi, MSI_MAX);
if (pos >= MSI_MAX) {
spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
return -ENOSPC;
}
__set_bit(pos, pcie->used_msi);
spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
irq_domain_set_info(dom, virq, pos, &tango_chip,
pcie, handle_edge_irq, NULL, NULL);
return 0;
}
static void tango_irq_domain_free(struct irq_domain *dom, unsigned int virq,
unsigned int nr_irqs)
{
unsigned long flags;
struct irq_data *d = irq_domain_get_irq_data(dom, virq);
struct tango_pcie *pcie = d->chip_data;
spin_lock_irqsave(&pcie->used_msi_lock, flags);
__clear_bit(d->hwirq, pcie->used_msi);
spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
}
static const struct irq_domain_ops dom_ops = {
.alloc = tango_irq_domain_alloc,
.free = tango_irq_domain_free,
};
static int smp8759_config_read(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 *val)
{
struct pci_config_window *cfg = bus->sysdata;
struct tango_pcie *pcie = dev_get_drvdata(cfg->parent);
int ret;
/* Reads in configuration space outside devfn 0 return garbage */
if (devfn != 0)
return PCIBIOS_FUNC_NOT_SUPPORTED;
/*
* PCI config and MMIO accesses are muxed. Linux doesn't have a
* mutual exclusion mechanism for config vs. MMIO accesses, so
* concurrent accesses may cause corruption.
*/
writel_relaxed(1, pcie->base + SMP8759_MUX);
ret = pci_generic_config_read(bus, devfn, where, size, val);
writel_relaxed(0, pcie->base + SMP8759_MUX);
return ret;
}
static int smp8759_config_write(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 val)
{
struct pci_config_window *cfg = bus->sysdata;
struct tango_pcie *pcie = dev_get_drvdata(cfg->parent);
int ret;
writel_relaxed(1, pcie->base + SMP8759_MUX);
ret = pci_generic_config_write(bus, devfn, where, size, val);
writel_relaxed(0, pcie->base + SMP8759_MUX);
return ret;
}
static struct pci_ecam_ops smp8759_ecam_ops = {
.bus_shift = 20,
.pci_ops = {
.map_bus = pci_ecam_map_bus,
.read = smp8759_config_read,
.write = smp8759_config_write,
}
};
static int tango_pcie_link_up(struct tango_pcie *pcie)
{
void __iomem *test_out = pcie->base + SMP8759_TEST_OUT;
int i;
writel_relaxed(16, test_out);
for (i = 0; i < 10; ++i) {
u32 ltssm_state = readl_relaxed(test_out) >> 8;
if ((ltssm_state & 0x1f) == 0xf) /* L0 */
return 1;
usleep_range(3000, 4000);
}
return 0;
}
static int tango_pcie_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct tango_pcie *pcie;
struct resource *res;
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