@@ -71,24 +71,31 @@ static void ring_interrupt_active(struct tb_ring *ring, bool active)
u32 step, shift, ivr, misc;
void __iomem *ivr_base;
int index;
+ int bit;
if (ring->is_tx)
index = ring->hop;
else
index = ring->hop + ring->nhi->hop_count;
- if (ring->nhi->quirks & QUIRK_AUTO_CLEAR_INT) {
- /*
- * Ask the hardware to clear interrupt status
- * bits automatically since we already know
- * which interrupt was triggered.
- */
- misc = ioread32(ring->nhi->iobase + REG_DMA_MISC);
- if (!(misc & REG_DMA_MISC_INT_AUTO_CLEAR)) {
- misc |= REG_DMA_MISC_INT_AUTO_CLEAR;
- iowrite32(misc, ring->nhi->iobase + REG_DMA_MISC);
- }
- }
+ /*
+ * Intel routers support a bit that isn't part of
+ * the USB4 spec to ask the hardware to clear
+ * interrupt status bits automatically since
+ * we already know which interrupt was triggered.
+ *
+ * Other routers explicitly disable auto-clear
+ * to prevent conditions that may occur where two
+ * MSIX interrupts are simultaneously active and
+ * reading the register clears both of them.
+ */
+ misc = ioread32(ring->nhi->iobase + REG_DMA_MISC);
+ if (ring->nhi->quirks & QUIRK_AUTO_CLEAR_INT)
+ bit = REG_DMA_MISC_INT_AUTO_CLEAR;
+ else
+ bit = REG_DMA_MISC_DISABLE_AUTO_CLEAR;
+ if (!(misc & bit))
+ iowrite32(misc | bit, ring->nhi->iobase + REG_DMA_MISC);
ivr_base = ring->nhi->iobase + REG_INT_VEC_ALLOC_BASE;
step = index / REG_INT_VEC_ALLOC_REGS * REG_INT_VEC_ALLOC_BITS;
@@ -393,14 +400,17 @@ EXPORT_SYMBOL_GPL(tb_ring_poll_complete);
static void ring_clear_msix(const struct tb_ring *ring)
{
+ int bit;
+
if (ring->nhi->quirks & QUIRK_AUTO_CLEAR_INT)
return;
+ bit = ring_interrupt_index(ring) & 31;
if (ring->is_tx)
- ioread32(ring->nhi->iobase + REG_RING_NOTIFY_BASE);
+ iowrite32(BIT(bit), ring->nhi->iobase + REG_RING_INT_CLEAR);
else
- ioread32(ring->nhi->iobase + REG_RING_NOTIFY_BASE +
- 4 * (ring->nhi->hop_count / 32));
+ iowrite32(BIT(bit), ring->nhi->iobase + REG_RING_INT_CLEAR +
+ 4 * (ring->nhi->hop_count / 32));
}
static irqreturn_t ring_msix(int irq, void *data)
@@ -77,12 +77,13 @@ struct ring_desc {
/*
* three bitfields: tx, rx, rx overflow
- * Every bitfield contains one bit for every hop (REG_HOP_COUNT). Registers are
- * cleared on read. New interrupts are fired only after ALL registers have been
+ * Every bitfield contains one bit for every hop (REG_HOP_COUNT).
+ * New interrupts are fired only after ALL registers have been
* read (even those containing only disabled rings).
*/
#define REG_RING_NOTIFY_BASE 0x37800
#define RING_NOTIFY_REG_COUNT(nhi) ((31 + 3 * nhi->hop_count) / 32)
+#define REG_RING_INT_CLEAR 0x37808
/*
* two bitfields: rx, tx
@@ -105,6 +106,7 @@ struct ring_desc {
#define REG_DMA_MISC 0x39864
#define REG_DMA_MISC_INT_AUTO_CLEAR BIT(2)
+#define REG_DMA_MISC_DISABLE_AUTO_CLEAR BIT(17)
#define REG_INMAIL_DATA 0x39900
When interrupt auto clear is programmed, any read to the interrupt status register will clear all interrupts. If two interrupts have come in before one can be serviced then this will cause lost interrupts. On AMD USB4 routers this has manifested in odd problems particularly with long strings of control tranfers such as reading the DROM via bit banging. Instead of clearing interrupts automatically, clear the bit corresponding to the given ring's interrupt in the ISR. Fixes: 7a1808f82a37 ("thunderbolt: Handle ring interrupt by reading interrupt status register") Cc: Sanju Mehta <Sanju.Mehta@amd.com> Tested-by: Anson Tsao <anson.tsao@amd.com> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> --- drivers/thunderbolt/nhi.c | 40 +++++++++++++++++++++------------- drivers/thunderbolt/nhi_regs.h | 6 +++-- 2 files changed, 29 insertions(+), 17 deletions(-)