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Date: Thu, 1 Dec 2022 09:23:33 -0800 From: Ira Weiny <ira.weiny@...el.com> To: Jonathan Cameron <Jonathan.Cameron@...wei.com> CC: Dan Williams <dan.j.williams@...el.com>, Alison Schofield <alison.schofield@...el.com>, Vishal Verma <vishal.l.verma@...el.com>, "Ben Widawsky" <bwidawsk@...nel.org>, Steven Rostedt <rostedt@...dmis.org>, Davidlohr Bueso <dave@...olabs.net>, Dave Jiang <dave.jiang@...el.com>, <linux-kernel@...r.kernel.org>, <linux-cxl@...r.kernel.org> Subject: Re: [PATCH V2 08/11] cxl/mem: Wire up event interrupts On Thu, Dec 01, 2022 at 02:21:18PM +0000, Jonathan Cameron wrote: > On Wed, 30 Nov 2022 16:27:16 -0800 > ira.weiny@...el.com wrote: > > > From: Ira Weiny <ira.weiny@...el.com> > > > > CXL device events are signaled via interrupts. Each event log may have > > a different interrupt message number. These message numbers are > > reported in the Get Event Interrupt Policy mailbox command. > > > > Add interrupt support for event logs. Interrupts are allocated as > > shared interrupts. Therefore, all or some event logs can share the same > > message number. > > > > Signed-off-by: Ira Weiny <ira.weiny@...el.com> > > A few trivial comments, but only superficially code style stuff which you > can ignore if you feel strongly about current style or it matches existing > file style etc... Thanks I'm leaving this one I think. > > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com> > > > > > --- > > Changes from V1: > > Remove unneeded evt_int_policy from struct cxl_dev_state > > defer Dynamic Capacity support > > Dave Jiang > > s/irq/rc > > use IRQ_NONE to signal the irq was not for us. > > Jonathan > > use msi_enabled rather than nr_irq_vec > > On failure explicitly set CXL_INT_NONE > > Add comment for Get Event Interrupt Policy > > use devm_request_threaded_irq() > > Use individual handler/thread functions for each of the > > logs rather than struct cxl_event_irq_id. > > > > Changes from RFC v2 > > Adjust to new irq 16 vector allocation > > Jonathan > > Remove CXL_INT_RES > > Use irq threads to ensure mailbox commands are executed outside irq context > > Adjust for optional Dynamic Capacity log > > --- > > drivers/cxl/core/mbox.c | 44 +++++++++++- > > drivers/cxl/cxlmem.h | 30 ++++++++ > > drivers/cxl/pci.c | 130 +++++++++++++++++++++++++++++++++++ > > include/uapi/linux/cxl_mem.h | 2 + > > 4 files changed, 204 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h > > index 450b410f29f6..2d384b0fc2b3 100644 > > --- a/drivers/cxl/cxlmem.h > > +++ b/drivers/cxl/cxlmem.h > > @@ -179,6 +179,30 @@ struct cxl_endpoint_dvsec_info { > > struct range dvsec_range[2]; > > }; > > > > +/** > > + * Event Interrupt Policy > > + * > > + * CXL rev 3.0 section 8.2.9.2.4; Table 8-52 > > + */ > > +enum cxl_event_int_mode { > > + CXL_INT_NONE = 0x00, > > + CXL_INT_MSI_MSIX = 0x01, > > + CXL_INT_FW = 0x02 > > +}; > > +#define CXL_EVENT_INT_MODE_MASK 0x3 > > +#define CXL_EVENT_INT_MSGNUM(setting) (((setting) & 0xf0) >> 4) > > +struct cxl_event_interrupt_policy { > > + u8 info_settings; > > + u8 warn_settings; > > + u8 failure_settings; > > + u8 fatal_settings; > > +} __packed; > > + > > +static inline bool cxl_evt_int_is_msi(u8 setting) > > +{ > > + return CXL_INT_MSI_MSIX == (setting & CXL_EVENT_INT_MODE_MASK); > > Maybe a case for FIELD_GET() though given the defines are all local > it is already obvious what this is doing so fine if you prefer to > keep it as is. > > > +} > ... > > > diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c > > index 11e95a95195a..3c0b9199f11a 100644 > > --- a/drivers/cxl/pci.c > > +++ b/drivers/cxl/pci.c > > @@ -449,6 +449,134 @@ static void cxl_pci_alloc_irq_vectors(struct cxl_dev_state *cxlds) > > cxlds->msi_enabled = true; > > } > > > > +static irqreturn_t cxl_event_info_thread(int irq, void *id) > > +{ > > + struct cxl_dev_state *cxlds = id; > > + > > + cxl_mem_get_records_log(cxlds, CXL_EVENT_TYPE_INFO); > > + return IRQ_HANDLED; > > +} > > I'm not a great fan of macros, but maybe this is a case for them. Nor am I. I particularly don't like when functions are defined with macros as it makes git grep and cscope harder to use on the code. > > > + > > +static irqreturn_t cxl_event_info_handler(int irq, void *id) > > +{ > > + struct cxl_dev_state *cxlds = id; > > + u32 status = readl(cxlds->regs.status + CXLDEV_DEV_EVENT_STATUS_OFFSET); > > Superficial and this is guaranteed to work (8.2.8 allow all sizes of read up > to 64 bytes), but maybe should treat this as a 64 bit register as that aligns > better with spec? I suppose it does. When I looked at that I only noticed the 32bit field and thought the register was 32bits. But most of our reads are to u32 fields. I think it is fine for now. > > > + > > + if (CXLDEV_EVENT_STATUS_INFO & status) > > Another maybe FIELD_GET() case? Are we using field get for individual bits? I see we are for some things. :-( I was thinking the 'field' is 'Event Status' and the 32 bit read of the register already got that. > > > + return IRQ_WAKE_THREAD; > > + return IRQ_NONE; > > +} > > + > > +static irqreturn_t cxl_event_warn_thread(int irq, void *id) > > +{ > > + struct cxl_dev_state *cxlds = id; > > Why id? Shortened from 'dev_id' from the devm_request_threaded_irq() function signature. > I'd call it what it is (maybe _cxlsd) and not bother with > the local variable in this case as it is only used once and doesn't > need the type. > > static irqreturn_t cxl_event_warn_thread(int irq, void *cxlds) > { > cxl_mem_get_records_log(cxlds, CXL_EVENT_TYPE_WARN); Yea in this case it is pretty clear but I hate having to look at function signatures to figure out what a (void *) callback type is supposed to be. This ... > > +static irqreturn_t cxl_event_warn_thread(int irq, void *id) > > +{ > > + struct cxl_dev_state *cxlds = id; ... helps to self document cxl_event_warn_thread() IMO, and the compiler will optimize. Thanks for looking! Ira > > return IRQ_HANDLED; > } > > > > + > > + cxl_mem_get_records_log(cxlds, CXL_EVENT_TYPE_WARN); > > + return IRQ_HANDLED; > > +} > > + > > ... > > >
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