| Message ID | 20211120000250.1663391-18-ben.widawsky@intel.com |
|---|---|
| State | New |
| Headers | show |
| Series | Add drivers for CXL ports and mem devices | expand |
Hi Ben,
I love your patch! Perhaps something to improve:
[auto build test WARNING on 53989fad1286e652ea3655ae3367ba698da8d2ff]
url: https://github.com/0day-ci/linux/commits/Ben-Widawsky/Add-drivers-for-CXL-ports-and-mem-devices/20211120-080513
base: 53989fad1286e652ea3655ae3367ba698da8d2ff
config: riscv-buildonly-randconfig-r001-20211119 (attached as .config)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install riscv cross compiling tool for clang build
# apt-get install binutils-riscv64-linux-gnu
# https://github.com/0day-ci/linux/commit/cfdf51e15fc8229a494ee59d05bc7459ab5eecd8
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Ben-Widawsky/Add-drivers-for-CXL-ports-and-mem-devices/20211120-080513
git checkout cfdf51e15fc8229a494ee59d05bc7459ab5eecd8
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=riscv
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
>> drivers/cxl/pci.c:469:7: warning: variable 'size' set but not used [-Wunused-but-set-variable]
u64 size;
^
1 warning generated.
vim +/size +469 drivers/cxl/pci.c
454
455 #define CDPD(cxlds, which) \
456 cxlds->device_dvsec + CXL_DVSEC_PCIE_DEVICE_##which##_OFFSET
457
458 #define CDPDR(cxlds, which, sorb, lohi) \
459 cxlds->device_dvsec + \
460 CXL_DVSEC_PCIE_DEVICE_RANGE_##sorb##_##lohi##_OFFSET(which)
461
462 static int wait_for_valid(struct cxl_dev_state *cxlds)
463 {
464 struct pci_dev *pdev = to_pci_dev(cxlds->dev);
465 const unsigned long timeout = jiffies + HZ;
466 bool valid;
467
468 do {
> 469 u64 size;
470 u32 temp;
471 int rc;
472
473 rc = pci_read_config_dword(pdev, CDPDR(cxlds, 0, SIZE, HIGH),
474 &temp);
475 if (rc)
476 return -ENXIO;
477 size = (u64)temp << 32;
478
479 rc = pci_read_config_dword(pdev, CDPDR(cxlds, 0, SIZE, LOW),
480 &temp);
481 if (rc)
482 return -ENXIO;
483 size |= temp & CXL_DVSEC_PCIE_DEVICE_MEM_SIZE_LOW_MASK;
484
485 /*
486 * Memory_Info_Valid: When set, indicates that the CXL Range 1
487 * Size high and Size Low registers are valid. Must be set
488 * within 1 second of deassertion of reset to CXL device.
489 */
490 valid = FIELD_GET(CXL_DVSEC_PCIE_DEVICE_MEM_INFO_VALID, temp);
491 if (valid)
492 break;
493 cpu_relax();
494 } while (!time_after(jiffies, timeout));
495
496 return valid ? 0 : -ETIMEDOUT;
497 }
498
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
On Fri, 19 Nov 2021 16:02:44 -0800 Ben Widawsky <ben.widawsky@intel.com> wrote: > CXL 1.1 specification provided a mechanism for mapping an address space > of a CXL device. That functionality is known as a "range" and can be > programmed through PCIe DVSEC. In addition to this, the specification > defines an active bit which a device will expose through the same DVSEC > to notify system software that memory is initialized and ready. > > While CXL 2.0 introduces a more powerful mechanism called HDM decoders > that are controlled by MMIO behind a PCIe BAR, the spec does allow the > 1.1 style mapping to still be present. In such a case, when the CXL > driver takes over, if it were to enable HDM decoding and there was an > actively used range, things would likely blow up, in particular if it > wasn't an identical mapping. > > This patch caches the relevant information which the cxl_mem driver will > need to make the proper decision and passes it along. > > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> 0-day spotted issues in same code as me. See below. This is another case where I'd treat failure as fatal. Anything that fails is either dead, or non spec compliant so don't bother loading the driver if that happens. Fewer paths to test etc... > --- > drivers/cxl/cxlmem.h | 19 +++++++ > drivers/cxl/pci.c | 126 +++++++++++++++++++++++++++++++++++++++++++ > drivers/cxl/pci.h | 13 +++++ > 3 files changed, 158 insertions(+) > > diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h > index 3ef3c652599e..eac5528ccaae 100644 > --- a/drivers/cxl/cxlmem.h > +++ b/drivers/cxl/cxlmem.h > @@ -89,6 +89,22 @@ struct cxl_mbox_cmd { > */ > #define CXL_CAPACITY_MULTIPLIER SZ_256M > > +/** > + * struct cxl_endpoint_dvsec_info - Cached DVSEC info > + * @mem_enabled: cached value of mem_enabled in the DVSEC, PCIE_DEVICE > + * @ranges: Number of HDM ranges this device contains. > + * @range.base: cached value of the range base in the DVSEC, PCIE_DEVICE > + * @range.size: cached value of the range size in the DVSEC, PCIE_DEVICE > + */ > +struct cxl_endpoint_dvsec_info { > + bool mem_enabled; > + int ranges; > + struct { > + u64 base; > + u64 size; > + } range[2]; > +}; > + > /** > * struct cxl_dev_state - The driver device state > * > @@ -117,6 +133,7 @@ struct cxl_mbox_cmd { > * @active_persistent_bytes: sum of hard + soft persistent > * @next_volatile_bytes: volatile capacity change pending device reset > * @next_persistent_bytes: persistent capacity change pending device reset > + * @info: Cached DVSEC information about the device. > * @mbox_send: @dev specific transport for transmitting mailbox commands > * > * See section 8.2.9.5.2 Capacity Configuration and Label Storage for > @@ -147,6 +164,8 @@ struct cxl_dev_state { > u64 next_volatile_bytes; > u64 next_persistent_bytes; > > + struct cxl_endpoint_dvsec_info *info; > + > int (*mbox_send)(struct cxl_dev_state *cxlds, struct cxl_mbox_cmd *cmd); > }; > > diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c > index f3872cbee7f8..b3f46045bf3e 100644 > --- a/drivers/cxl/pci.c > +++ b/drivers/cxl/pci.c > @@ -452,8 +452,126 @@ static int cxl_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type, > return rc; > } > > +#define CDPD(cxlds, which) \ > + cxlds->device_dvsec + CXL_DVSEC_PCIE_DEVICE_##which##_OFFSET My usual grumble :) I personally find macros like this a bit of a pain when reviewing. I'd really like to see things spelled out in the code so I can immediately see what register we are dealing with even if it does seem rather repetitive in the code. > + > +#define CDPDR(cxlds, which, sorb, lohi) \ > + cxlds->device_dvsec + \ > + CXL_DVSEC_PCIE_DEVICE_RANGE_##sorb##_##lohi##_OFFSET(which) > + > +static int wait_for_valid(struct cxl_dev_state *cxlds) > +{ > + struct pci_dev *pdev = to_pci_dev(cxlds->dev); > + const unsigned long timeout = jiffies + HZ; > + bool valid; > + > + do { > + u64 size; > + u32 temp; > + int rc; > + > + rc = pci_read_config_dword(pdev, CDPDR(cxlds, 0, SIZE, HIGH), > + &temp); > + if (rc) > + return -ENXIO; > + size = (u64)temp << 32; > + > + rc = pci_read_config_dword(pdev, CDPDR(cxlds, 0, SIZE, LOW), > + &temp); > + if (rc) > + return -ENXIO; > + size |= temp & CXL_DVSEC_PCIE_DEVICE_MEM_SIZE_LOW_MASK; > + > + /* > + * Memory_Info_Valid: When set, indicates that the CXL Range 1 > + * Size high and Size Low registers are valid. Must be set > + * within 1 second of deassertion of reset to CXL device. > + */ > + valid = FIELD_GET(CXL_DVSEC_PCIE_DEVICE_MEM_INFO_VALID, temp); > + if (valid) > + break; I think there is a race here. What if you read the high part, get garbage and then read the low part which is now valid... Swap this around so you read this one first and it will be fine. However given as 0-day pointed out, size isn't used, this is fine anyway (subject to removing the pointless code). > + cpu_relax(); > + } while (!time_after(jiffies, timeout)); > + > + return valid ? 0 : -ETIMEDOUT; > +} > + > +static struct cxl_endpoint_dvsec_info *dvsec_ranges(struct cxl_dev_state *cxlds) > +{ > + struct pci_dev *pdev = to_pci_dev(cxlds->dev); > + struct cxl_endpoint_dvsec_info *info; > + int hdm_count, rc, i; > + u16 cap, ctrl; > + > + rc = pci_read_config_word(pdev, CDPD(cxlds, CAP), &cap); > + if (rc) > + return ERR_PTR(-ENXIO); > + rc = pci_read_config_word(pdev, CDPD(cxlds, CTRL), &ctrl); > + if (rc) > + return ERR_PTR(-ENXIO); > + > + if (!(cap & CXL_DVSEC_PCIE_DEVICE_MEM_CAPABLE)) > + return ERR_PTR(-ENODEV); > + > + /* > + * It is not allowed by spec for MEM.capable to be set and have 0 HDM > + * decoders. Therefore, the device is not considered CXL.mem capable. > + */ > + hdm_count = FIELD_GET(CXL_DVSEC_PCIE_DEVICE_HDM_COUNT_MASK, cap); > + if (!hdm_count || hdm_count > 2) > + return ERR_PTR(-EINVAL); > + > + rc = wait_for_valid(cxlds); > + if (rc) > + return ERR_PTR(rc); > + > + info = devm_kzalloc(cxlds->dev, sizeof(*info), GFP_KERNEL); > + if (!info) > + return ERR_PTR(-ENOMEM); > + > + info->mem_enabled = FIELD_GET(CXL_DVSEC_PCIE_DEVICE_MEM_ENABLE, ctrl); > + > + for (i = 0; i < hdm_count; i++) { > + u64 base, size; > + u32 temp; > + > + rc = pci_read_config_dword(pdev, CDPDR(cxlds, i, SIZE, HIGH), > + &temp); > + if (rc) > + continue; > + size = (u64)temp << 32; > + > + rc = pci_read_config_dword(pdev, CDPDR(cxlds, i, SIZE, LOW), > + &temp); > + if (rc) > + continue; > + size |= temp & CXL_DVSEC_PCIE_DEVICE_MEM_SIZE_LOW_MASK; > + > + rc = pci_read_config_dword(pdev, CDPDR(cxlds, i, BASE, HIGH), > + &temp); > + if (rc) > + continue; > + base = (u64)temp << 32; > + > + rc = pci_read_config_dword(pdev, CDPDR(cxlds, i, BASE, LOW), > + &temp); > + if (rc) > + continue; > + base |= temp & CXL_DVSEC_PCIE_DEVICE_MEM_BASE_LOW_MASK; > + > + info->range[i].base = base; > + info->range[i].size = size; > + info->ranges++; > + } > + > + return info; > +} > + > +#undef CDPDR > + > static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > { > + struct cxl_endpoint_dvsec_info *info; > struct cxl_register_map map; > struct cxl_memdev *cxlmd; > struct cxl_dev_state *cxlds; > @@ -505,6 +623,14 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > if (rc) > return rc; > > + info = dvsec_ranges(cxlds); > + if (IS_ERR(info)) > + dev_err(&pdev->dev, > + "Failed to get DVSEC range information (%ld)\n", > + PTR_ERR(info)); > + else > + cxlds->info = info; > + > cxlmd = devm_cxl_add_memdev(cxlds); > if (IS_ERR(cxlmd)) > return PTR_ERR(cxlmd);
On 21-11-22 17:00:56, Jonathan Cameron wrote: > On Fri, 19 Nov 2021 16:02:44 -0800 > Ben Widawsky <ben.widawsky@intel.com> wrote: > > > CXL 1.1 specification provided a mechanism for mapping an address space > > of a CXL device. That functionality is known as a "range" and can be > > programmed through PCIe DVSEC. In addition to this, the specification > > defines an active bit which a device will expose through the same DVSEC > > to notify system software that memory is initialized and ready. > > > > While CXL 2.0 introduces a more powerful mechanism called HDM decoders > > that are controlled by MMIO behind a PCIe BAR, the spec does allow the > > 1.1 style mapping to still be present. In such a case, when the CXL > > driver takes over, if it were to enable HDM decoding and there was an > > actively used range, things would likely blow up, in particular if it > > wasn't an identical mapping. > > > > This patch caches the relevant information which the cxl_mem driver will > > need to make the proper decision and passes it along. > > > > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> > > 0-day spotted issues in same code as me. See below. > > This is another case where I'd treat failure as fatal. Anything that fails > is either dead, or non spec compliant so don't bother loading the driver > if that happens. Fewer paths to test etc... I disagree about treating failure as fatal. The failure here only forbids using the memory on the device. I can envision firmware bugs or the like where these things might fail, but the mailbox interfaces still work perfectly fine, or at least fine enough to upgrade the firmware and try again. Dan and I had talked about a modparam (or perhaps sysfs on some higher level, like CXL bus) to control the length of the timeout, so that one doesn't have to wait forever to deal with this usage. Figured we'd cross that bridge when we came to it. > > > --- > > drivers/cxl/cxlmem.h | 19 +++++++ > > drivers/cxl/pci.c | 126 +++++++++++++++++++++++++++++++++++++++++++ > > drivers/cxl/pci.h | 13 +++++ > > 3 files changed, 158 insertions(+) > > > > diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h > > index 3ef3c652599e..eac5528ccaae 100644 > > --- a/drivers/cxl/cxlmem.h > > +++ b/drivers/cxl/cxlmem.h > > @@ -89,6 +89,22 @@ struct cxl_mbox_cmd { > > */ > > #define CXL_CAPACITY_MULTIPLIER SZ_256M > > > > +/** > > + * struct cxl_endpoint_dvsec_info - Cached DVSEC info > > + * @mem_enabled: cached value of mem_enabled in the DVSEC, PCIE_DEVICE > > + * @ranges: Number of HDM ranges this device contains. > > + * @range.base: cached value of the range base in the DVSEC, PCIE_DEVICE > > + * @range.size: cached value of the range size in the DVSEC, PCIE_DEVICE > > + */ > > +struct cxl_endpoint_dvsec_info { > > + bool mem_enabled; > > + int ranges; > > + struct { > > + u64 base; > > + u64 size; > > + } range[2]; > > +}; > > + > > /** > > * struct cxl_dev_state - The driver device state > > * > > @@ -117,6 +133,7 @@ struct cxl_mbox_cmd { > > * @active_persistent_bytes: sum of hard + soft persistent > > * @next_volatile_bytes: volatile capacity change pending device reset > > * @next_persistent_bytes: persistent capacity change pending device reset > > + * @info: Cached DVSEC information about the device. > > * @mbox_send: @dev specific transport for transmitting mailbox commands > > * > > * See section 8.2.9.5.2 Capacity Configuration and Label Storage for > > @@ -147,6 +164,8 @@ struct cxl_dev_state { > > u64 next_volatile_bytes; > > u64 next_persistent_bytes; > > > > + struct cxl_endpoint_dvsec_info *info; > > + > > int (*mbox_send)(struct cxl_dev_state *cxlds, struct cxl_mbox_cmd *cmd); > > }; > > > > diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c > > index f3872cbee7f8..b3f46045bf3e 100644 > > --- a/drivers/cxl/pci.c > > +++ b/drivers/cxl/pci.c > > @@ -452,8 +452,126 @@ static int cxl_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type, > > return rc; > > } > > > > +#define CDPD(cxlds, which) \ > > + cxlds->device_dvsec + CXL_DVSEC_PCIE_DEVICE_##which##_OFFSET > > My usual grumble :) I personally find macros like this a bit of a pain when > reviewing. I'd really like to see things spelled out in the code so I > can immediately see what register we are dealing with even if it does > seem rather repetitive in the code. I understand. It's this or have every line look strange because of character limits. I agree that whomever writes this stuff can reason it out better, and that makes it harder on reviewers. I don't mind changing it back, I'd like hear any other opinions before I do though. > > > + > > +#define CDPDR(cxlds, which, sorb, lohi) \ > > + cxlds->device_dvsec + \ > > + CXL_DVSEC_PCIE_DEVICE_RANGE_##sorb##_##lohi##_OFFSET(which) > > + > > +static int wait_for_valid(struct cxl_dev_state *cxlds) > > +{ > > + struct pci_dev *pdev = to_pci_dev(cxlds->dev); > > + const unsigned long timeout = jiffies + HZ; > > + bool valid; > > + > > + do { > > + u64 size; > > + u32 temp; > > + int rc; > > + > > + rc = pci_read_config_dword(pdev, CDPDR(cxlds, 0, SIZE, HIGH), > > + &temp); > > + if (rc) > > + return -ENXIO; > > + size = (u64)temp << 32; > > + > > + rc = pci_read_config_dword(pdev, CDPDR(cxlds, 0, SIZE, LOW), > > + &temp); > > + if (rc) > > + return -ENXIO; > > + size |= temp & CXL_DVSEC_PCIE_DEVICE_MEM_SIZE_LOW_MASK; > > + > > + /* > > + * Memory_Info_Valid: When set, indicates that the CXL Range 1 > > + * Size high and Size Low registers are valid. Must be set > > + * within 1 second of deassertion of reset to CXL device. > > + */ > > + valid = FIELD_GET(CXL_DVSEC_PCIE_DEVICE_MEM_INFO_VALID, temp); > > + if (valid) > > + break; > > I think there is a race here. What if you read the high part, get garbage and then > read the low part which is now valid... > > Swap this around so you read this one first and it will be fine. > > However given as 0-day pointed out, size isn't used, this is fine anyway > (subject to removing the pointless code). > Yes. I've fixed that. And you're right, size is potentially invalid in this case even if it found the valid bit. > > + cpu_relax(); > > + } while (!time_after(jiffies, timeout)); > > + > > + return valid ? 0 : -ETIMEDOUT; > > +} > > + > > +static struct cxl_endpoint_dvsec_info *dvsec_ranges(struct cxl_dev_state *cxlds) > > +{ > > + struct pci_dev *pdev = to_pci_dev(cxlds->dev); > > + struct cxl_endpoint_dvsec_info *info; > > + int hdm_count, rc, i; > > + u16 cap, ctrl; > > + > > + rc = pci_read_config_word(pdev, CDPD(cxlds, CAP), &cap); > > + if (rc) > > + return ERR_PTR(-ENXIO); > > + rc = pci_read_config_word(pdev, CDPD(cxlds, CTRL), &ctrl); > > + if (rc) > > + return ERR_PTR(-ENXIO); > > + > > + if (!(cap & CXL_DVSEC_PCIE_DEVICE_MEM_CAPABLE)) > > + return ERR_PTR(-ENODEV); > > + > > + /* > > + * It is not allowed by spec for MEM.capable to be set and have 0 HDM > > + * decoders. Therefore, the device is not considered CXL.mem capable. > > + */ > > + hdm_count = FIELD_GET(CXL_DVSEC_PCIE_DEVICE_HDM_COUNT_MASK, cap); > > + if (!hdm_count || hdm_count > 2) > > + return ERR_PTR(-EINVAL); > > + > > + rc = wait_for_valid(cxlds); > > + if (rc) > > + return ERR_PTR(rc); > > + > > + info = devm_kzalloc(cxlds->dev, sizeof(*info), GFP_KERNEL); > > + if (!info) > > + return ERR_PTR(-ENOMEM); > > + > > + info->mem_enabled = FIELD_GET(CXL_DVSEC_PCIE_DEVICE_MEM_ENABLE, ctrl); > > + > > + for (i = 0; i < hdm_count; i++) { > > + u64 base, size; > > + u32 temp; > > + > > + rc = pci_read_config_dword(pdev, CDPDR(cxlds, i, SIZE, HIGH), > > + &temp); > > + if (rc) > > + continue; > > + size = (u64)temp << 32; > > + > > + rc = pci_read_config_dword(pdev, CDPDR(cxlds, i, SIZE, LOW), > > + &temp); > > + if (rc) > > + continue; > > + size |= temp & CXL_DVSEC_PCIE_DEVICE_MEM_SIZE_LOW_MASK; > > + > > + rc = pci_read_config_dword(pdev, CDPDR(cxlds, i, BASE, HIGH), > > + &temp); > > + if (rc) > > + continue; > > + base = (u64)temp << 32; > > + > > + rc = pci_read_config_dword(pdev, CDPDR(cxlds, i, BASE, LOW), > > + &temp); > > + if (rc) > > + continue; > > + base |= temp & CXL_DVSEC_PCIE_DEVICE_MEM_BASE_LOW_MASK; > > + > > + info->range[i].base = base; > > + info->range[i].size = size; > > + info->ranges++; > > + } > > + > > + return info; > > +} > > + > > +#undef CDPDR > > + > > static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > > { > > + struct cxl_endpoint_dvsec_info *info; > > struct cxl_register_map map; > > struct cxl_memdev *cxlmd; > > struct cxl_dev_state *cxlds; > > @@ -505,6 +623,14 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > > if (rc) > > return rc; > > > > + info = dvsec_ranges(cxlds); > > + if (IS_ERR(info)) > > + dev_err(&pdev->dev, > > + "Failed to get DVSEC range information (%ld)\n", > > + PTR_ERR(info)); > > + else > > + cxlds->info = info; > > + > > cxlmd = devm_cxl_add_memdev(cxlds); > > if (IS_ERR(cxlmd)) > > return PTR_ERR(cxlmd); > >
On Fri, 19 Nov 2021 16:02:44 -0800 Ben Widawsky <ben.widawsky@intel.com> wrote: > CXL 1.1 specification provided a mechanism for mapping an address space > of a CXL device. That functionality is known as a "range" and can be > programmed through PCIe DVSEC. In addition to this, the specification > defines an active bit which a device will expose through the same DVSEC > to notify system software that memory is initialized and ready. > > While CXL 2.0 introduces a more powerful mechanism called HDM decoders > that are controlled by MMIO behind a PCIe BAR, the spec does allow the > 1.1 style mapping to still be present. In such a case, when the CXL > driver takes over, if it were to enable HDM decoding and there was an > actively used range, things would likely blow up, in particular if it > wasn't an identical mapping. > > This patch caches the relevant information which the cxl_mem driver will > need to make the proper decision and passes it along. > > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> > --- > drivers/cxl/cxlmem.h | 19 +++++++ > drivers/cxl/pci.c | 126 +++++++++++++++++++++++++++++++++++++++++++ > drivers/cxl/pci.h | 13 +++++ > 3 files changed, 158 insertions(+) > > diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h > index 3ef3c652599e..eac5528ccaae 100644 > --- a/drivers/cxl/cxlmem.h > +++ b/drivers/cxl/cxlmem.h > @@ -89,6 +89,22 @@ struct cxl_mbox_cmd { > */ > #define CXL_CAPACITY_MULTIPLIER SZ_256M > > +/** > + * struct cxl_endpoint_dvsec_info - Cached DVSEC info > + * @mem_enabled: cached value of mem_enabled in the DVSEC, PCIE_DEVICE > + * @ranges: Number of HDM ranges this device contains. > + * @range.base: cached value of the range base in the DVSEC, PCIE_DEVICE > + * @range.size: cached value of the range size in the DVSEC, PCIE_DEVICE > + */ > +struct cxl_endpoint_dvsec_info { > + bool mem_enabled; > + int ranges; > + struct { > + u64 base; > + u64 size; > + } range[2]; kernel-doc wants documentation for range as well. > +};
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h index 3ef3c652599e..eac5528ccaae 100644 --- a/drivers/cxl/cxlmem.h +++ b/drivers/cxl/cxlmem.h @@ -89,6 +89,22 @@ struct cxl_mbox_cmd { */ #define CXL_CAPACITY_MULTIPLIER SZ_256M +/** + * struct cxl_endpoint_dvsec_info - Cached DVSEC info + * @mem_enabled: cached value of mem_enabled in the DVSEC, PCIE_DEVICE + * @ranges: Number of HDM ranges this device contains. + * @range.base: cached value of the range base in the DVSEC, PCIE_DEVICE + * @range.size: cached value of the range size in the DVSEC, PCIE_DEVICE + */ +struct cxl_endpoint_dvsec_info { + bool mem_enabled; + int ranges; + struct { + u64 base; + u64 size; + } range[2]; +}; + /** * struct cxl_dev_state - The driver device state * @@ -117,6 +133,7 @@ struct cxl_mbox_cmd { * @active_persistent_bytes: sum of hard + soft persistent * @next_volatile_bytes: volatile capacity change pending device reset * @next_persistent_bytes: persistent capacity change pending device reset + * @info: Cached DVSEC information about the device. * @mbox_send: @dev specific transport for transmitting mailbox commands * * See section 8.2.9.5.2 Capacity Configuration and Label Storage for @@ -147,6 +164,8 @@ struct cxl_dev_state { u64 next_volatile_bytes; u64 next_persistent_bytes; + struct cxl_endpoint_dvsec_info *info; + int (*mbox_send)(struct cxl_dev_state *cxlds, struct cxl_mbox_cmd *cmd); }; diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c index f3872cbee7f8..b3f46045bf3e 100644 --- a/drivers/cxl/pci.c +++ b/drivers/cxl/pci.c @@ -452,8 +452,126 @@ static int cxl_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type, return rc; } +#define CDPD(cxlds, which) \ + cxlds->device_dvsec + CXL_DVSEC_PCIE_DEVICE_##which##_OFFSET + +#define CDPDR(cxlds, which, sorb, lohi) \ + cxlds->device_dvsec + \ + CXL_DVSEC_PCIE_DEVICE_RANGE_##sorb##_##lohi##_OFFSET(which) + +static int wait_for_valid(struct cxl_dev_state *cxlds) +{ + struct pci_dev *pdev = to_pci_dev(cxlds->dev); + const unsigned long timeout = jiffies + HZ; + bool valid; + + do { + u64 size; + u32 temp; + int rc; + + rc = pci_read_config_dword(pdev, CDPDR(cxlds, 0, SIZE, HIGH), + &temp); + if (rc) + return -ENXIO; + size = (u64)temp << 32; + + rc = pci_read_config_dword(pdev, CDPDR(cxlds, 0, SIZE, LOW), + &temp); + if (rc) + return -ENXIO; + size |= temp & CXL_DVSEC_PCIE_DEVICE_MEM_SIZE_LOW_MASK; + + /* + * Memory_Info_Valid: When set, indicates that the CXL Range 1 + * Size high and Size Low registers are valid. Must be set + * within 1 second of deassertion of reset to CXL device. + */ + valid = FIELD_GET(CXL_DVSEC_PCIE_DEVICE_MEM_INFO_VALID, temp); + if (valid) + break; + cpu_relax(); + } while (!time_after(jiffies, timeout)); + + return valid ? 0 : -ETIMEDOUT; +} + +static struct cxl_endpoint_dvsec_info *dvsec_ranges(struct cxl_dev_state *cxlds) +{ + struct pci_dev *pdev = to_pci_dev(cxlds->dev); + struct cxl_endpoint_dvsec_info *info; + int hdm_count, rc, i; + u16 cap, ctrl; + + rc = pci_read_config_word(pdev, CDPD(cxlds, CAP), &cap); + if (rc) + return ERR_PTR(-ENXIO); + rc = pci_read_config_word(pdev, CDPD(cxlds, CTRL), &ctrl); + if (rc) + return ERR_PTR(-ENXIO); + + if (!(cap & CXL_DVSEC_PCIE_DEVICE_MEM_CAPABLE)) + return ERR_PTR(-ENODEV); + + /* + * It is not allowed by spec for MEM.capable to be set and have 0 HDM + * decoders. Therefore, the device is not considered CXL.mem capable. + */ + hdm_count = FIELD_GET(CXL_DVSEC_PCIE_DEVICE_HDM_COUNT_MASK, cap); + if (!hdm_count || hdm_count > 2) + return ERR_PTR(-EINVAL); + + rc = wait_for_valid(cxlds); + if (rc) + return ERR_PTR(rc); + + info = devm_kzalloc(cxlds->dev, sizeof(*info), GFP_KERNEL); + if (!info) + return ERR_PTR(-ENOMEM); + + info->mem_enabled = FIELD_GET(CXL_DVSEC_PCIE_DEVICE_MEM_ENABLE, ctrl); + + for (i = 0; i < hdm_count; i++) { + u64 base, size; + u32 temp; + + rc = pci_read_config_dword(pdev, CDPDR(cxlds, i, SIZE, HIGH), + &temp); + if (rc) + continue; + size = (u64)temp << 32; + + rc = pci_read_config_dword(pdev, CDPDR(cxlds, i, SIZE, LOW), + &temp); + if (rc) + continue; + size |= temp & CXL_DVSEC_PCIE_DEVICE_MEM_SIZE_LOW_MASK; + + rc = pci_read_config_dword(pdev, CDPDR(cxlds, i, BASE, HIGH), + &temp); + if (rc) + continue; + base = (u64)temp << 32; + + rc = pci_read_config_dword(pdev, CDPDR(cxlds, i, BASE, LOW), + &temp); + if (rc) + continue; + base |= temp & CXL_DVSEC_PCIE_DEVICE_MEM_BASE_LOW_MASK; + + info->range[i].base = base; + info->range[i].size = size; + info->ranges++; + } + + return info; +} + +#undef CDPDR + static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) { + struct cxl_endpoint_dvsec_info *info; struct cxl_register_map map; struct cxl_memdev *cxlmd; struct cxl_dev_state *cxlds; @@ -505,6 +623,14 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) if (rc) return rc; + info = dvsec_ranges(cxlds); + if (IS_ERR(info)) + dev_err(&pdev->dev, + "Failed to get DVSEC range information (%ld)\n", + PTR_ERR(info)); + else + cxlds->info = info; + cxlmd = devm_cxl_add_memdev(cxlds); if (IS_ERR(cxlmd)) return PTR_ERR(cxlmd); diff --git a/drivers/cxl/pci.h b/drivers/cxl/pci.h index a4b506bb37d1..2a48cd65bf59 100644 --- a/drivers/cxl/pci.h +++ b/drivers/cxl/pci.h @@ -15,6 +15,19 @@ /* CXL 2.0 8.1.3: PCIe DVSEC for CXL Device */ #define CXL_DVSEC_PCIE_DEVICE 0 +#define CXL_DVSEC_PCIE_DEVICE_CAP_OFFSET 0xA +#define CXL_DVSEC_PCIE_DEVICE_MEM_CAPABLE BIT(2) +#define CXL_DVSEC_PCIE_DEVICE_HDM_COUNT_MASK GENMASK(5, 4) +#define CXL_DVSEC_PCIE_DEVICE_CTRL_OFFSET 0xC +#define CXL_DVSEC_PCIE_DEVICE_MEM_ENABLE BIT(2) +#define CXL_DVSEC_PCIE_DEVICE_RANGE_SIZE_HIGH_OFFSET(i) 0x18 + (i * 0x10) +#define CXL_DVSEC_PCIE_DEVICE_RANGE_SIZE_LOW_OFFSET(i) 0x1C + (i * 0x10) +#define CXL_DVSEC_PCIE_DEVICE_MEM_INFO_VALID BIT(0) +#define CXL_DVSEC_PCIE_DEVICE_MEM_ACTIVE BIT(1) +#define CXL_DVSEC_PCIE_DEVICE_MEM_SIZE_LOW_MASK GENMASK(31, 28) +#define CXL_DVSEC_PCIE_DEVICE_RANGE_BASE_HIGH_OFFSET(i) 0x20 + (i * 0x10) +#define CXL_DVSEC_PCIE_DEVICE_RANGE_BASE_LOW_OFFSET(i) 0x24 + (i * 0x10) +#define CXL_DVSEC_PCIE_DEVICE_MEM_BASE_LOW_MASK GENMASK(31, 28) /* CXL 2.0 8.1.4: Non-CXL Function Map DVSEC */ #define CXL_DVSEC_FUNCTION_MAP 2
CXL 1.1 specification provided a mechanism for mapping an address space of a CXL device. That functionality is known as a "range" and can be programmed through PCIe DVSEC. In addition to this, the specification defines an active bit which a device will expose through the same DVSEC to notify system software that memory is initialized and ready. While CXL 2.0 introduces a more powerful mechanism called HDM decoders that are controlled by MMIO behind a PCIe BAR, the spec does allow the 1.1 style mapping to still be present. In such a case, when the CXL driver takes over, if it were to enable HDM decoding and there was an actively used range, things would likely blow up, in particular if it wasn't an identical mapping. This patch caches the relevant information which the cxl_mem driver will need to make the proper decision and passes it along. Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> --- drivers/cxl/cxlmem.h | 19 +++++++ drivers/cxl/pci.c | 126 +++++++++++++++++++++++++++++++++++++++++++ drivers/cxl/pci.h | 13 +++++ 3 files changed, 158 insertions(+)