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Re: [Qemu-block] [Qemu-devel] [PATCH 7/9] AHCI: Rework IRQ constants
From: |
John Snow |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH 7/9] AHCI: Rework IRQ constants |
Date: |
Mon, 28 Aug 2017 20:28:03 -0400 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 |
On 08/25/2017 10:00 AM, Philippe Mathieu-Daudé wrote:
> Hi John,
>
> On 08/08/2017 03:33 PM, John Snow wrote:
>> Create a new enum so that we can name the IRQ bits, which will make
>> debugging
>> them a little nicer if we can print them out. Not handled in this
>> patch, but
>> this will make it possible to get a nice debug printf detailing
>> exactly which
>> status bits are set, as it can be multiple at any given time.
>>
>> As a consequence of this patch, it is no longer possible to set
>> multiple IRQ
>> codes at once, but nothing was utilizing this ability anyway.
>>
>> Signed-off-by: John Snow <address@hidden>
>> ---
>> hw/ide/ahci.c | 49
>> ++++++++++++++++++++++++++++++++++++++-----------
>> hw/ide/ahci_internal.h | 44
>> +++++++++++++++++++++++++++++++++++---------
>> hw/ide/trace-events | 2 +-
>> 3 files changed, 74 insertions(+), 21 deletions(-)
>>
>> diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
>> index d5acceb..c5a9b69 100644
>> --- a/hw/ide/ahci.c
>> +++ b/hw/ide/ahci.c
>> @@ -56,6 +56,27 @@ static bool ahci_map_fis_address(AHCIDevice *ad);
>> static void ahci_unmap_clb_address(AHCIDevice *ad);
>> static void ahci_unmap_fis_address(AHCIDevice *ad);
>> +static const char *AHCIPortIRQ_lookup[AHCI_PORT_IRQ__END] = {
>> + [AHCI_PORT_IRQ_BIT_DHRS] = "DHRS",
>> + [AHCI_PORT_IRQ_BIT_PSS] = "PSS",
>> + [AHCI_PORT_IRQ_BIT_DSS] = "DSS",
>> + [AHCI_PORT_IRQ_BIT_SDBS] = "SDBS",
>> + [AHCI_PORT_IRQ_BIT_UFS] = "UFS",
>> + [AHCI_PORT_IRQ_BIT_DPS] = "DPS",
>> + [AHCI_PORT_IRQ_BIT_PCS] = "PCS",
>> + [AHCI_PORT_IRQ_BIT_DMPS] = "DMPS",
>> + [8 ... 21] = "RESERVED",
>> + [AHCI_PORT_IRQ_BIT_PRCS] = "PRCS",
>> + [AHCI_PORT_IRQ_BIT_IPMS] = "IPMS",
>> + [AHCI_PORT_IRQ_BIT_OFS] = "OFS",
>> + [25] = "RESERVED",
>> + [AHCI_PORT_IRQ_BIT_INFS] = "INFS",
>> + [AHCI_PORT_IRQ_BIT_IFS] = "IFS",
>> + [AHCI_PORT_IRQ_BIT_HBDS] = "HBDS",
>> + [AHCI_PORT_IRQ_BIT_HBFS] = "HBFS",
>> + [AHCI_PORT_IRQ_BIT_TFES] = "TFES",
>> + [AHCI_PORT_IRQ_BIT_CPDS] = "CPDS"
>> +};
>> static uint32_t ahci_port_read(AHCIState *s, int port, int offset)
>> {
>> @@ -170,12 +191,18 @@ static void ahci_check_irq(AHCIState *s)
>> }
>> static void ahci_trigger_irq(AHCIState *s, AHCIDevice *d,
>> - int irq_type)
>> + enum AHCIPortIRQ irqbit)
>> {
>> - DPRINTF(d->port_no, "trigger irq %#x -> %x\n",
>> - irq_type, d->port_regs.irq_mask & irq_type);
>> + g_assert(irqbit >= 0 && irqbit < 32);
>
> Since you now use an enum this check is no more necessary.
>
You can actually still pass in a wrong value if you wanted to. This is
to prevent old-style IRQ masks from getting passed in by accident.
> However ...
>
>> + uint32_t irq = 1U << irqbit;
>> + uint32_t irqstat = d->port_regs.irq_stat | irq;
>> - d->port_regs.irq_stat |= irq_type;
>> + trace_ahci_trigger_irq(s, d->port_no,
>> + AHCIPortIRQ_lookup[irqbit], irq,
>> + d->port_regs.irq_stat, irqstat,
>> + irqstat & d->port_regs.irq_mask);
>> +
>
> Why not keep using masked irqs, and iterate over AHCI_PORT_IRQ__END
> bits? Something like:
>
> if (TRACE_AHCI_IRQ_ENABLED) {
> int irqbit;
> for (irqbit = 0; irqbit < AHCI_PORT_IRQ__END; irqbit++) {
> if (irqmask & BIT(irqbit)) {
> trace_ahci_trigger_irq(s, d->port_no, ...
>
Would rather not iterate like that for the IRQ path. Generally no place
in the codebase needs to raise more than one IRQ type at a time, so why
bother allowing it?