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Simple VME FMC Carrier SVEC - Software
Commit c600af76 authored by Tomasz Wlostowski's avatar Tomasz Wlostowski
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kernel: fix edge emulation timeout & check for subsequent VIC IRQs before… 

kernel: fix edge emulation timeout & check for subsequent VIC IRQs before returning from the handler.

The latter keeps handling VIC irqs in a loop until none of the IRQ lines is active anymore. This prevents
situations when two or more IRQs come almost simultaneously (e.g. reading sychronized sample buffers) and the one with
lower priority gets starved.
parent 531f2d45
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Showing with 20 additions and 12 deletions
kernel/svec-vic.c
View file @ c600af76
......@@ -87,10 +87,10 @@ static int svec_vic_init(struct svec_dev *svec, struct fmc_device *fmc)
vic->vectors[i].saved_id =
vic_readl(vic, VIC_IVT_RAM_BASE + 4 * i);
/* configure the VIC output: active high, edge sensitive, pulse widhth = 1 tick (16 ns) */
/* configure the VIC output: active high, edge sensitive, pulse width = 1 tick (16 ns) */
vic_writel(vic,
VIC_CTL_ENABLE | VIC_CTL_POL | VIC_CTL_EMU_EDGE |
VIC_CTL_EMU_LEN_W(1), VIC_REG_CTL);
VIC_CTL_EMU_LEN_W(40000), VIC_REG_CTL); /* 160 us IRQ retry timer */
vic->initialized = 1;
svec->vic = vic;
......@@ -116,20 +116,28 @@ irqreturn_t svec_vic_irq_dispatch(struct svec_dev * svec)
int index, rv;
struct vector *vec;
/* Our parent IRQ handler: read the index value from the Vector Address Register,
and find matching handler */
index = vic_readl(vic, VIC_REG_VAR) & 0xff;
do {
/* Our parent IRQ handler: read the index value from the Vector Address Register,
and find matching handler */
index = vic_readl(vic, VIC_REG_VAR) & 0xff;
if (index >= VIC_MAX_VECTORS)
goto fail;
if (index >= VIC_MAX_VECTORS)
goto fail;
vec = &vic->vectors[index];
if (!vec->handler)
goto fail;
vec = &vic->vectors[index];
if (!vec->handler)
goto fail;
rv = vec->handler(vec->saved_id, vec->requestor);
rv = vec->handler(vec->saved_id, vec->requestor);
vic_writel(vic, 0, VIC_REG_EOIR); /* ack the irq */
vic_writel(vic, 0, VIC_REG_EOIR); /* ack the irq */
if(rv < 0)
break;
/* check if any IRQ is still pending */
} while (vic_readl(vic, VIC_REG_RISR));
return rv;
fail:
......
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