On Fri, 7 Jan 2022 08:33:41 -0800
Ben Widawsky <ben.widawsky@xxxxxxxxx> wrote:
> On 22-01-07 16:18:12, Jonathan Cameron wrote:
> > On Thu, 6 Jan 2022 16:37:56 -0800
> > Ben Widawsky <ben.widawsky@xxxxxxxxx> wrote:
> >
> > > Do the HDM decoder programming for all endpoints and host bridges in a
> > > region. Switches are currently unimplemented.
> > >
> > > Signed-off-by: Ben Widawsky <ben.widawsky@xxxxxxxxx>
> > > ---
> > > drivers/cxl/core/hdm.c | 198 +++++++++++++++++++++++++++++++++++++++++
> > > drivers/cxl/cxl.h | 3 +
> > > drivers/cxl/region.c | 39 +++++++-
> > > 3 files changed, 237 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> > > index 44e48cea8cd4..c7293cbd8547 100644
> > > --- a/drivers/cxl/core/hdm.c
> > > +++ b/drivers/cxl/core/hdm.c
> > > @@ -242,3 +242,201 @@ int devm_cxl_enumerate_switch_decoders(struct cxl_port *port)
> > > return 0;
> > > }
> > > EXPORT_SYMBOL_NS_GPL(devm_cxl_enumerate_switch_decoders, CXL);
> > > +
> > > +#define COMMIT_TIMEOUT_MS 10
> > > +static int wait_for_commit(struct cxl_decoder *cxld)
> > > +{
> > > + struct cxl_port *port = to_cxl_port(cxld->dev.parent);
> > > + const unsigned long start = jiffies;
> > > + struct cxl_port_state *cxlps;
> > > + void __iomem *hdm_decoder;
> > > + unsigned long end = start;
> > > + u32 ctrl;
> > > +
> > > + cxlps = dev_get_drvdata(&port->dev);
> > > + hdm_decoder = cxlps->regs.hdm_decoder;
> > > +
> > > + do {
> > > + end = jiffies;
> > > + ctrl = readl(hdm_decoder +
> > > + CXL_HDM_DECODER0_CTRL_OFFSET(cxld->id));
> > > + if (FIELD_GET(CXL_HDM_DECODER0_CTRL_COMMITTED, ctrl))
> > > + break;
> > > +
> > > + if (time_after(end, start + COMMIT_TIMEOUT_MS)) {
> > > + dev_err(&cxld->dev, "HDM decoder commit timeout %x\n", ctrl);
> > > + return -ETIMEDOUT;
> > > + }
> > > + if ((ctrl & CXL_HDM_DECODER0_CTRL_COMMIT_ERROR) != 0) {
> > > + dev_err(&cxld->dev, "HDM decoder commit error %x\n", ctrl);
> > > + return -ENXIO;
> > > + }
> > > + } while (FIELD_GET(CXL_HDM_DECODER0_CTRL_COMMITTED, ctrl));
> >
> > Hi Ben,
> >
> > Thanks for posting this btw - it's very helpful indeed for hammering out bugs
> > in the qemu code and to identify what isn't there yet.
> >
> > Took me a while to work out how this seemed to succeed on QEMU with no
> > implementation of the commit for the host bridges (just adding that now ;)
> > Reason is this condition is inverse of what I think you intend.
> >
> > Given you have an exit condition above this could probably just be a while (1)
> > loop.
> >
> > Jonathan
>
> Quick response without looking at code. I thought I did implement this in QEMU,
> but you're correct that the logic is inverted. If you have a QEMU branch for me
> to use when I fix this, please let me know.
The branch I got from your gitlab has it specifically for the type3 device, but
not more generally.
Qemu wise will see if I can hammer something into a shape to share but might take
a little while to hammer out remaining bugs. I've made a few fiddly changes to
try and simplify the setup + avoid fixed PA address ranges anywhere.
Jonathan
>
> >
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +/**
> > > + * cxl_commit_decoder() - Program a configured cxl_decoder
> > > + * @cxld: The preconfigured cxl decoder.
> > > + *
> > > + * A cxl decoder that is to be committed should have been earmarked as enabled.
> > > + * This mechanism acts as a soft reservation on the decoder.
> > > + *
> > > + * Returns 0 if commit was successful, negative error code otherwise.
> > > + */
> > > +int cxl_commit_decoder(struct cxl_decoder *cxld)
> > > +{
> > > + u32 ctrl, tl_lo, tl_hi, base_lo, base_hi, size_lo, size_hi;
> > > + struct cxl_port *port = to_cxl_port(cxld->dev.parent);
> > > + struct cxl_port_state *cxlps;
> > > + void __iomem *hdm_decoder;
> > > + int rc;
> > > +
> > > + /*
> > > + * Decoder flags are entirely software controlled and therefore this
> > > + * case is purely a driver bug.
> > > + */
> > > + if (dev_WARN_ONCE(&port->dev, (cxld->flags & CXL_DECODER_F_ENABLE) != 0,
> > > + "Invalid %s enable state\n", dev_name(&cxld->dev)))
> > > + return -ENXIO;
> > > +
> > > + cxlps = dev_get_drvdata(&port->dev);
> > > + hdm_decoder = cxlps->regs.hdm_decoder;
> > > + ctrl = readl(hdm_decoder + CXL_HDM_DECODER0_CTRL_OFFSET(cxld->id));
> > > +
> > > + /*
> > > + * A decoder that's currently active cannot be changed without the
> > > + * system being quiesced. While the driver should prevent against this,
> > > + * for a variety of reasons the hardware might not be in sync with the
> > > + * hardware and so, do not splat on error.
> > > + */
> > > + size_hi = readl(hdm_decoder +
> > > + CXL_HDM_DECODER0_SIZE_HIGH_OFFSET(cxld->id));
> > > + size_lo =
> > > + readl(hdm_decoder + CXL_HDM_DECODER0_SIZE_LOW_OFFSET(cxld->id));
> > > + if (FIELD_GET(CXL_HDM_DECODER0_CTRL_COMMITTED, ctrl) &&
> > > + (size_lo + size_hi)) {
> > > + dev_err(&port->dev, "Tried to change an active decoder (%s)\n",
> > > + dev_name(&cxld->dev));
> > > + return -EBUSY;
> > > + }
> > > +
> > > + u32p_replace_bits(&ctrl, 8 - ilog2(cxld->interleave_granularity),
> > > + CXL_HDM_DECODER0_CTRL_IG_MASK);
> > > + u32p_replace_bits(&ctrl, ilog2(cxld->interleave_ways),
> > > + CXL_HDM_DECODER0_CTRL_IW_MASK);
> > > + u32p_replace_bits(&ctrl, 1, CXL_HDM_DECODER0_CTRL_COMMIT);
> > > +
> > > + /* TODO: set based on type */
> > > + u32p_replace_bits(&ctrl, 1, CXL_HDM_DECODER0_CTRL_TYPE);
> > > +
> > > + base_lo = FIELD_PREP(GENMASK(31, 28),
> > > + (u32)(cxld->decoder_range.start & 0xffffffff));
> > > + base_hi = FIELD_PREP(~0, (u32)(cxld->decoder_range.start >> 32));
> > > +
> > > + size_lo = (u32)(range_len(&cxld->decoder_range)) & GENMASK(31, 28);
> > > + size_hi = (u32)((range_len(&cxld->decoder_range) >> 32));
> > > +
> > > + if (cxld->nr_targets > 0) {
> > > + tl_lo |= FIELD_PREP(GENMASK(7, 0), cxld->target[0]->port_id);
> > > + if (cxld->interleave_ways > 1)
> > > + tl_lo |= FIELD_PREP(GENMASK(15, 8),
> > > + cxld->target[1]->port_id);
> > > + if (cxld->interleave_ways > 2)
> > > + tl_lo |= FIELD_PREP(GENMASK(23, 16),
> > > + cxld->target[2]->port_id);
> > > + if (cxld->interleave_ways > 3)
> > > + tl_lo |= FIELD_PREP(GENMASK(31, 24),
> > > + cxld->target[3]->port_id);
> > > + if (cxld->interleave_ways > 4)
> > > + tl_hi |= FIELD_PREP(GENMASK(7, 0),
> > > + cxld->target[4]->port_id);
> > > + if (cxld->interleave_ways > 5)
> > > + tl_hi |= FIELD_PREP(GENMASK(15, 8),
> > > + cxld->target[5]->port_id);
> > > + if (cxld->interleave_ways > 6)
> > > + tl_hi |= FIELD_PREP(GENMASK(23, 16),
> > > + cxld->target[6]->port_id);
> > > + if (cxld->interleave_ways > 7)
> > > + tl_hi |= FIELD_PREP(GENMASK(31, 24),
> > > + cxld->target[7]->port_id);
> > > +
> > > + writel(tl_hi, hdm_decoder + CXL_HDM_DECODER0_TL_HIGH(cxld->id));
> > > + writel(tl_lo, hdm_decoder + CXL_HDM_DECODER0_TL_LOW(cxld->id));
> > > + }
> > > +
> > > + writel(size_hi,
> > > + hdm_decoder + CXL_HDM_DECODER0_SIZE_HIGH_OFFSET(cxld->id));
> > > + writel(size_lo,
> > > + hdm_decoder + CXL_HDM_DECODER0_SIZE_LOW_OFFSET(cxld->id));
> > > + writel(base_hi,
> > > + hdm_decoder + CXL_HDM_DECODER0_BASE_HIGH_OFFSET(cxld->id));
> > > + writel(base_lo,
> > > + hdm_decoder + CXL_HDM_DECODER0_BASE_LOW_OFFSET(cxld->id));
> > > + writel(ctrl, hdm_decoder + CXL_HDM_DECODER0_CTRL_OFFSET(cxld->id));
> > > +
> > > + rc = wait_for_commit(cxld);
> > > + if (rc)
> > > + return rc;
> > > +
> > > + cxld->flags |= CXL_DECODER_F_ENABLE;
> > > +
> > > +#define DPORT_TL_STR "%d %d %d %d %d %d %d %d"
> > > +#define DPORT(i) \
> > > + (cxld->nr_targets && cxld->interleave_ways > (i)) ? \
> > > + cxld->target[(i)]->port_id : \
> > > + -1
> > > +#define DPORT_TL \
> > > + DPORT(0), DPORT(1), DPORT(2), DPORT(3), DPORT(4), DPORT(5), DPORT(6), \
> > > + DPORT(7)
> > > +
> > > + dev_dbg(&port->dev,
> > > + "%s\n\tBase %pa\n\tSize %llu\n\tIG %u\n\tIW %u\n\tTargetList: " DPORT_TL_STR,
> > > + dev_name(&cxld->dev), &cxld->decoder_range.start,
> > > + range_len(&cxld->decoder_range), cxld->interleave_granularity,
> > > + cxld->interleave_ways, DPORT_TL);
> > > +#undef DPORT_TL
> > > +#undef DPORT
> > > +#undef DPORT_TL_STR
> > > + return 0;
> > > +}
> > > +EXPORT_SYMBOL_GPL(cxl_commit_decoder);
> > > +
> > > +/**
> > > + * cxl_disable_decoder() - Disables a decoder
> > > + * @cxld: The active cxl decoder.
> > > + *
> > > + * CXL decoders (as of 2.0 spec) have no way to deactivate them other than to
> > > + * set the size of the HDM to 0. This function will clear all registers, and if
> > > + * the decoder is active, commit the 0'd out registers.
> > > + */
> > > +void cxl_disable_decoder(struct cxl_decoder *cxld)
> > > +{
> > > + struct cxl_port *port = to_cxl_port(cxld->dev.parent);
> > > + struct cxl_port_state *cxlps;
> > > + void __iomem *hdm_decoder;
> > > + u32 ctrl;
> > > +
> > > + cxlps = dev_get_drvdata(&port->dev);
> > > + hdm_decoder = cxlps->regs.hdm_decoder;
> > > + ctrl = readl(hdm_decoder + CXL_HDM_DECODER0_CTRL_OFFSET(cxld->id));
> > > +
> > > + if (dev_WARN_ONCE(&port->dev, (cxld->flags & CXL_DECODER_F_ENABLE) == 0,
> > > + "Invalid decoder enable state\n"))
> > > + return;
> > > +
> > > + /* There's no way to "uncommit" a committed decoder, only 0 size it */
> > > + writel(0, hdm_decoder + CXL_HDM_DECODER0_TL_HIGH(cxld->id));
> > > + writel(0, hdm_decoder + CXL_HDM_DECODER0_TL_LOW(cxld->id));
> > > + writel(0, hdm_decoder + CXL_HDM_DECODER0_SIZE_HIGH_OFFSET(cxld->id));
> > > + writel(0, hdm_decoder + CXL_HDM_DECODER0_SIZE_LOW_OFFSET(cxld->id));
> > > + writel(0, hdm_decoder + CXL_HDM_DECODER0_BASE_HIGH_OFFSET(cxld->id));
> > > + writel(0, hdm_decoder + CXL_HDM_DECODER0_BASE_LOW_OFFSET(cxld->id));
> > > +
> > > + /* If the device isn't actually active, just zero out all the fields */
> > > + if (FIELD_GET(CXL_HDM_DECODER0_CTRL_COMMITTED, ctrl))
> > > + writel(CXL_HDM_DECODER0_CTRL_COMMIT,
> > > + hdm_decoder + CXL_HDM_DECODER0_CTRL_OFFSET(cxld->id));
> > > +}
> > > +EXPORT_SYMBOL_GPL(cxl_disable_decoder);
> > > diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> > > index 79bca9a8246c..587b75f7fa53 100644
> > > --- a/drivers/cxl/cxl.h
> > > +++ b/drivers/cxl/cxl.h
> > > @@ -54,6 +54,7 @@
> > > #define CXL_HDM_DECODER0_CTRL_IW_MASK GENMASK(7, 4)
> > > #define CXL_HDM_DECODER0_CTRL_COMMIT BIT(9)
> > > #define CXL_HDM_DECODER0_CTRL_COMMITTED BIT(10)
> > > +#define CXL_HDM_DECODER0_CTRL_COMMIT_ERROR BIT(11)
> > > #define CXL_HDM_DECODER0_CTRL_TYPE BIT(12)
> > > #define CXL_HDM_DECODER0_TL_LOW(i) (0x20 * (i) + 0x24)
> > > #define CXL_HDM_DECODER0_TL_HIGH(i) (0x20 * (i) + 0x28)
> > > @@ -364,6 +365,8 @@ int devm_cxl_add_dport(struct cxl_port *port, struct device *dport, int port_id,
> > > struct cxl_dport *cxl_find_dport_by_dev(struct cxl_port *port,
> > > const struct device *dev);
> > > struct cxl_port *ep_find_cxl_port(struct cxl_memdev *cxlmd, unsigned int depth);
> > > +int cxl_commit_decoder(struct cxl_decoder *cxld);
> > > +void cxl_disable_decoder(struct cxl_decoder *cxld);
> > >
> > > struct cxl_decoder *to_cxl_decoder(struct device *dev);
> > > bool is_cxl_decoder(struct device *dev);
> > > diff --git a/drivers/cxl/region.c b/drivers/cxl/region.c
> > > index 3120b65b0bc5..fd82d37ba573 100644
> > > --- a/drivers/cxl/region.c
> > > +++ b/drivers/cxl/region.c
> > > @@ -580,10 +580,30 @@ static void cleanup_staged_decoders(struct cxl_region *region)
> > > }
> > > }
> > >
> > > -static int bind_region(const struct cxl_region *region)
> > > +static int bind_region(struct cxl_region *region)
> > > {
> > > - /* TODO: */
> > > - return 0;
> > > + struct cxl_decoder *cxld, *d;
> > > + int rc;
> > > +
> > > + list_for_each_entry_safe(cxld, d, ®ion->staged_list, region_link) {
> > > + rc = cxl_commit_decoder(cxld);
> > > + if (!rc)
> > > + list_move_tail(&cxld->region_link, ®ion->commit_list);
> > > + else
> > > + break;
> > > + }
> > > +
> > > + list_for_each_entry_safe(cxld, d, ®ion->commit_list, region_link) {
> > > + if (rc)
> > > + cxl_disable_decoder(cxld);
> > > + list_del(&cxld->region_link);
> > > + }
> > > +
> > > + if (rc)
> > > + cleanup_staged_decoders((struct cxl_region *)region);
> > > +
> > > + BUG_ON(!list_empty(®ion->staged_list));
> > > + return rc;
> > > }
> > >
> > > static int cxl_region_probe(struct device *dev)
> > > @@ -650,9 +670,22 @@ static int cxl_region_probe(struct device *dev)
> > > return ret;
> > > }
> > >
> > > +static void cxl_region_remove(struct device *dev)
> > > +{
> > > + struct cxl_region *region = to_cxl_region(dev);
> > > + struct cxl_decoder *cxld, *d;
> > > +
> > > + list_for_each_entry_safe(cxld, d, ®ion->commit_list, region_link) {
> > > + cxl_disable_decoder(cxld);
> > > + list_del(&cxld->region_link);
> > > + cxl_put_decoder(cxld);
> > > + }
> > > +}
> > > +
> > > static struct cxl_driver cxl_region_driver = {
> > > .name = "cxl_region",
> > > .probe = cxl_region_probe,
> > > + .remove = cxl_region_remove,
> > > .id = CXL_DEVICE_REGION,
> > > };
> > > module_cxl_driver(cxl_region_driver);
> >
