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Message-ID: <6483ecb5a4526_e067a29490@dwillia2-xfh.jf.intel.com.notmuch>
Date: Fri, 9 Jun 2023 20:23:33 -0700
From: Dan Williams <dan.j.williams@...el.com>
To: Terry Bowman <terry.bowman@....com>, <alison.schofield@...el.com>,
<vishal.l.verma@...el.com>, <ira.weiny@...el.com>,
<bwidawsk@...nel.org>, <dan.j.williams@...el.com>,
<dave.jiang@...el.com>, <Jonathan.Cameron@...wei.com>,
<linux-cxl@...r.kernel.org>
CC: <terry.bowman@....com>, <rrichter@....com>,
<linux-kernel@...r.kernel.org>, <bhelgaas@...gle.com>
Subject: RE: [PATCH v5 22/26] cxl/pci: Map RCH downstream AER registers for
logging protocol errors
Terry Bowman wrote:
> The restricted CXL host (RCH) error handler will log protocol errors
> using AER and RAS status registers. The AER and RAS registers need
> to be virtually memory mapped before enabling interrupts. Update
> __devm_cxl_add_dport() to include RCH RAS and AER mapping.
>
> Add 'struct cxl_regs' to 'struct cxl_dport' for saving a unique copy of
> the RCH downstream port's mapped registers.
>
> Co-developed-by: Robert Richter <rrichter@....com>
> Signed-off-by: Robert Richter <rrichter@....com>
> Signed-off-by: Terry Bowman <terry.bowman@....com>
> ---
> drivers/cxl/core/port.c | 38 ++++++++++++++++++++++++++++++++++++++
> drivers/cxl/core/regs.c | 1 +
> drivers/cxl/cxl.h | 11 +++++++++++
> 3 files changed, 50 insertions(+)
>
> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> index 3111f754c740..bc5d0ee9da54 100644
> --- a/drivers/cxl/core/port.c
> +++ b/drivers/cxl/core/port.c
> @@ -8,6 +8,7 @@
> #include <linux/pci.h>
> #include <linux/slab.h>
> #include <linux/idr.h>
> +#include <linux/aer.h>
> #include <cxlmem.h>
> #include <cxlpci.h>
> #include <cxl.h>
> @@ -947,6 +948,39 @@ static void cxl_dport_unlink(void *data)
> sysfs_remove_link(&port->dev.kobj, link_name);
> }
>
> +static int cxl_dport_map_rch_aer(struct cxl_dport *dport)
> +{
> + struct cxl_rcrb_info *ri = &dport->rcrb;
> + resource_size_t aer_phys;
> + void __iomem *dport_aer;
> +
> + if (!dport->rch || !ri->aer_cap)
> + return -ENODEV;
> +
> + aer_phys = ri->aer_cap + ri->base;
> + dport_aer = devm_cxl_iomap_block(dport->dev, aer_phys,
> + sizeof(struct aer_capability_regs));
@dport->dev is not suitable to be the @host argument to
devm_cxl_iomap_block(). It needs to match the lifetime of the @dport
allocation which means @host needs to be set to @port->dev.
> + if (!dport_aer)
> + return -ENOMEM;
> +
> + dport->regs.dport_aer = dport_aer;
> +
> + return 0;
> +}
> +
> +static int cxl_dport_map_regs(struct cxl_dport *dport)
> +{
> + struct cxl_register_map *map = &dport->comp_map;
> +
> + if (!map->component_map.ras.valid)
> + dev_dbg(map->dev, "RAS registers not found\n");
> + else if (cxl_map_component_regs(map, &dport->regs.component,
> + BIT(CXL_CM_CAP_CAP_ID_RAS)))
> + dev_dbg(dport->dev, "Failed to map RAS capability.\n");
> +
> + return cxl_dport_map_rch_aer(dport);
> +}
> +
> static struct cxl_dport *
> __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
> int port_id, resource_size_t component_reg_phys,
> @@ -1000,6 +1034,10 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
> if (rc && rc != -ENODEV)
> return ERR_PTR(rc);
>
> + rc = cxl_dport_map_regs(dport);
> + if (rc && rc != -ENODEV)
> + return ERR_PTR(rc);
I'll repeat the previous comment about replacing:
if (rc && rc != -ENODEV)
...with an optional initialization at alloc time.
> +
> cond_cxl_root_lock(port);
> rc = add_dport(port, dport);
> cond_cxl_root_unlock(port);
> diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
> index dd6c3c898cff..26fb4f395365 100644
> --- a/drivers/cxl/core/regs.c
> +++ b/drivers/cxl/core/regs.c
> @@ -198,6 +198,7 @@ void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr,
>
> return ret_val;
> }
> +EXPORT_SYMBOL_NS_GPL(devm_cxl_iomap_block, CXL);
>
> int cxl_map_component_regs(struct cxl_register_map *map,
> struct cxl_component_regs *regs,
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 6134644b51f8..0e0bcbefefaf 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -209,6 +209,13 @@ struct cxl_regs {
> struct_group_tagged(cxl_device_regs, device_regs,
> void __iomem *status, *mbox, *memdev;
> );
> + /*
> + * RCH downstream port specific RAS register
> + * @aer: CXL 3.0 8.2.1.1 RCH Downstream Port RCRB
> + */
> + struct_group_tagged(cxl_rch_regs, rch_regs,
> + void __iomem *dport_aer;
> + );
> };
>
> struct cxl_reg_map {
> @@ -255,6 +262,8 @@ void cxl_probe_component_regs(struct device *dev, void __iomem *base,
> struct cxl_component_reg_map *map);
> void cxl_probe_device_regs(struct device *dev, void __iomem *base,
> struct cxl_device_reg_map *map);
> +void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr,
> + resource_size_t length);
> int cxl_map_component_regs(struct cxl_register_map *map,
> struct cxl_component_regs *regs,
> unsigned long map_mask);
> @@ -603,6 +612,7 @@ struct cxl_rcrb_info {
> * @port_id: unique hardware identifier for dport in decoder target list
> * @rch: Indicate whether this dport was enumerated in RCH or VH mode
> * @rcrb: Data about the Root Complex Register Block layout
> + * @regs: Dport parsed register blocks
> */
> struct cxl_dport {
> struct device *dev;
> @@ -611,6 +621,7 @@ struct cxl_dport {
> int port_id;
> bool rch;
> struct cxl_rcrb_info rcrb;
> + struct cxl_regs regs;
> };
>
> /**
> --
> 2.34.1
>
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