| Message ID | 20201111054356.793390-3-ben.widawsky@intel.com (mailing list archive) |
|---|---|
| State | RFC, archived |
| Headers | show |
| Series | CXL 2.0 Support | expand |
On Tue, 10 Nov 2020 21:43:49 -0800 Ben Widawsky <ben.widawsky@intel.com> wrote: > From: Vishal Verma <vishal.l.verma@intel.com> > > Add support to advertise OS capabilities, and request OS control for CXL > features using the ACPI _OSC mechanism. Advertise support for all > possible CXL features, and attempt to request control too for all > possible features. > > Based on a patch by Sean Kelley. > > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> I guess unsurprisingly a lot of this is cut and paste from PCIe so can we share some of the code? Thanks, Jonathan > > --- > > This uses a non-standard UUID for CXL and is meant as a change proposal > to the CXL specification. The definition for _OSC intermixes PCIe and > CXL Dwords, which makes a clean separation of CXL capabilities > difficult, if not impossible. This is therefore subject to change. > > --- > drivers/cxl/acpi.c | 210 ++++++++++++++++++++++++++++++++++++++++++++- > drivers/cxl/acpi.h | 18 ++++ > 2 files changed, 226 insertions(+), 2 deletions(-) > > diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c > index 26e4f73838a7..c3e2f7f6ea02 100644 > --- a/drivers/cxl/acpi.c > +++ b/drivers/cxl/acpi.c > @@ -12,6 +12,16 @@ > #include <linux/pci.h> > #include "acpi.h" > > +/* > + * TODO: These are global for now to save the OSC state. > + * This works if OSC can be expected to be uniform for every ACPI0016 object. > + * If that is not the case, revisit this. These need to be saved because > + * relinquishing control of a previously granted capability is disallowed. > + */ > +static u32 cxl_osc_support_set; > +static u32 cxl_osc_control_set; > +static DEFINE_MUTEX(acpi_desc_lock); > + > static void acpi_cxl_desc_init(struct acpi_cxl_desc *acpi_desc, struct device *dev) > { > dev_set_drvdata(dev, acpi_desc); > @@ -74,6 +84,199 @@ static struct acpi_driver acpi_cxl_driver = { > }, > }; > > +struct pci_osc_bit_struct { > + u32 bit; > + char *desc; > +}; > + > +static struct pci_osc_bit_struct cxl_osc_support_bit[] = { > + { CXL_OSC_PORT_REG_ACCESS_SUPPORT, "CXLPortRegAccess" }, > + { CXL_OSC_PORT_DEV_REG_ACCESS_SUPPORT, "CXLPortDevRegAccess" }, > + { CXL_OSC_PER_SUPPORT, "CXLProtocolErrorReporting" }, > + { CXL_OSC_NATIVE_HP_SUPPORT, "CXLNativeHotPlug" }, > +}; > + > +static struct pci_osc_bit_struct cxl_osc_control_bit[] = { > + { CXL_OSC_MEM_ERROR_CONTROL, "CXLMemErrorReporting" }, > +}; > + > +/* > + * CXL 2.0 spec UUID - unusable as it PCI and CXL OSC are mixed > + * static u8 cxl_osc_uuid_str[] = "68F2D50B-C469-4d8A-BD3D-941A103FD3FC"; > + */ > +/* New, proposed UUID for CXL-only OSC */ > +static u8 cxl_osc_uuid_str[] = "A4D1629D-FF52-4888-BE96-E5CADE548DB1"; > + > +static void decode_osc_bits(struct device *dev, char *msg, u32 word, > + struct pci_osc_bit_struct *table, int size) > +{ > + char buf[80]; > + int i, len = 0; > + struct pci_osc_bit_struct *entry; > + > + buf[0] = '\0'; > + for (i = 0, entry = table; i < size; i++, entry++) > + if (word & entry->bit) > + len += scnprintf(buf + len, sizeof(buf) - len, "%s%s", > + len ? " " : "", entry->desc); > + > + dev_info(dev, "_OSC: %s [%s]\n", msg, buf); Can we look at sharing code with PCI? > +} > + > +static void decode_cxl_osc_support(struct device *dev, char *msg, u32 word) > +{ > + decode_osc_bits(dev, msg, word, cxl_osc_support_bit, > + ARRAY_SIZE(cxl_osc_support_bit)); > +} > + > +static void decode_cxl_osc_control(struct device *dev, char *msg, u32 word) > +{ > + decode_osc_bits(dev, msg, word, cxl_osc_control_bit, > + ARRAY_SIZE(cxl_osc_control_bit)); > +} > + > +static acpi_status acpi_cap_run_osc(acpi_handle handle, > + const u32 *capbuf, u8 *uuid_str, u32 *retval) > +{ > + struct acpi_osc_context context = { > + .uuid_str = uuid_str, > + .rev = 1, > + .cap.length = 20, > + .cap.pointer = (void *)capbuf, > + }; > + acpi_status status; > + > + status = acpi_run_osc(handle, &context); > + if (ACPI_SUCCESS(status)) { > + *retval = *((u32 *)(context.ret.pointer + 8)); > + kfree(context.ret.pointer); > + } > + return status; > +} > + > +static acpi_status cxl_query_osc(acpi_handle handle, u32 support, u32 *control) > +{ > + acpi_status status; > + u32 result, capbuf[5]; > + > + support &= CXL_OSC_SUPPORT_VALID_MASK; > + support |= cxl_osc_support_set; > + > + capbuf[OSC_QUERY_DWORD] = OSC_QUERY_ENABLE; > + capbuf[CXL_OSC_SUPPORT_DWORD] = support; > + if (control) { > + *control &= CXL_OSC_CONTROL_VALID_MASK; > + capbuf[CXL_OSC_CONTROL_DWORD] = *control | cxl_osc_control_set; > + } else { > + /* Run _OSC query only with existing controls. */ > + capbuf[CXL_OSC_CONTROL_DWORD] = cxl_osc_control_set; > + } > + > + status = acpi_cap_run_osc(handle, capbuf, cxl_osc_uuid_str, &result); > + if (ACPI_SUCCESS(status)) { > + cxl_osc_support_set = support; > + if (control) > + *control = result; > + } > + return status; > +} > + > +static acpi_status cxl_osc_advertise_support(acpi_handle handle, u32 flags) > +{ > + acpi_status status; > + > + mutex_lock(&acpi_desc_lock); > + status = cxl_query_osc(handle, flags, NULL); > + mutex_unlock(&acpi_desc_lock); > + return status; > +} > + > +/** > + * cxl_osc_request_control - Request control of CXL root _OSC features. > + * @adev: ACPI device for the PCI root bridge (or PCIe Root Complex). > + * @mask: Mask of _OSC bits to request control of, place to store control mask. > + * @req: Mask of _OSC bits the control of is essential to the caller. > + **/ > +static acpi_status cxl_osc_request_control(struct acpi_device *adev, u32 *mask, u32 req) > +{ > + acpi_handle handle = adev->handle; > + struct device *dev = &adev->dev; > + acpi_status status = AE_OK; > + u32 ctrl, capbuf[5]; > + > + if (!mask) > + return AE_BAD_PARAMETER; > + > + ctrl = *mask & CXL_OSC_MEM_ERROR_CONTROL; > + if ((ctrl & req) != req) > + return AE_TYPE; > + > + mutex_lock(&acpi_desc_lock); > + > + *mask = ctrl | cxl_osc_control_set; > + /* No need to evaluate _OSC if the control was already granted. */ > + if ((cxl_osc_control_set & ctrl) == ctrl) > + goto out; > + > + /* Need to check the available controls bits before requesting them. */ > + while (*mask) { > + status = cxl_query_osc(handle, cxl_osc_support_set, mask); > + if (ACPI_FAILURE(status)) > + goto out; > + if (ctrl == *mask) > + break; > + decode_cxl_osc_control(dev, "platform does not support", ctrl & ~(*mask)); > + ctrl = *mask; > + } > + > + if ((ctrl & req) != req) { > + decode_cxl_osc_control(dev, "not requesting control; platform does not support", > + req & ~(ctrl)); > + status = AE_SUPPORT; > + goto out; > + } > + > + capbuf[OSC_QUERY_DWORD] = 0; > + capbuf[CXL_OSC_SUPPORT_DWORD] = cxl_osc_support_set; > + capbuf[CXL_OSC_CONTROL_DWORD] = ctrl; > + status = acpi_cap_run_osc(handle, capbuf, cxl_osc_uuid_str, mask); > + if (ACPI_SUCCESS(status)) > + cxl_osc_control_set = *mask; > +out: > + mutex_unlock(&acpi_desc_lock); > + return status; > +} > + > +static int cxl_negotiate_osc(struct acpi_device *adev) > +{ > + u32 cxl_support, cxl_control, requested; > + acpi_handle handle = adev->handle; > + struct device *dev = &adev->dev; > + acpi_status status; > + > + /* Declare support for everything */ > + cxl_support = CXL_OSC_SUPPORT_VALID_MASK; > + decode_cxl_osc_support(dev, "OS supports", cxl_support); > + status = cxl_osc_advertise_support(handle, cxl_support); > + if (ACPI_FAILURE(status)) { > + dev_info(dev, "CXL_OSC failed (%s)\n", acpi_format_exception(status)); > + return -ENXIO; > + } > + > + /* Request control for everything */ > + cxl_control = CXL_OSC_CONTROL_VALID_MASK; > + requested = cxl_control; > + status = cxl_osc_request_control(adev, &cxl_control, CXL_OSC_MEM_ERROR_CONTROL); > + if (ACPI_SUCCESS(status)) { > + decode_cxl_osc_control(dev, "OS now controls", cxl_control); > + } else { > + decode_cxl_osc_control(dev, "OS requested", requested); > + decode_cxl_osc_control(dev, "platform willing to grant", cxl_control); > + dev_info(dev, "_OSC failed (%s)\n", acpi_format_exception(status)); > + } > + return 0; > +} > + > /* > * If/when CXL support is defined by other platform firmware the kernel > * will need a mechanism to select between the platform specific version > @@ -84,6 +287,7 @@ int cxl_bus_prepared(struct pci_dev *pdev) > struct acpi_device *adev; > struct pci_dev *root_port; > struct device *root; > + int rc; > > root_port = pcie_find_root_port(pdev); > if (!root_port) > @@ -97,9 +301,11 @@ int cxl_bus_prepared(struct pci_dev *pdev) > if (!adev) > return -ENXIO; > > - /* TODO: OSC enabling */ > + rc = cxl_negotiate_osc(adev); > + if (rc) > + dev_err(&pdev->dev, "Failed to negotiate OSC\n"); > > - return 0; > + return rc; > } > EXPORT_SYMBOL_GPL(cxl_bus_prepared); > > diff --git a/drivers/cxl/acpi.h b/drivers/cxl/acpi.h > index 011505475cc6..bf8d078e1b2a 100644 > --- a/drivers/cxl/acpi.h > +++ b/drivers/cxl/acpi.h > @@ -10,6 +10,24 @@ struct acpi_cxl_desc { > struct device *dev; > }; > > +/* Indexes into _OSC Capabilities Buffer */ > +#define CXL_OSC_SUPPORT_DWORD 1 /* DWORD 2 */ > +#define CXL_OSC_CONTROL_DWORD 2 /* DWORD 3 */ > + > +/* CXL Host Bridge _OSC: Capabilities DWORD 2: Support Field */ > +#define CXL_OSC_PORT_REG_ACCESS_SUPPORT 0x00000001 > +#define CXL_OSC_PORT_DEV_REG_ACCESS_SUPPORT 0x00000002 > +#define CXL_OSC_PER_SUPPORT 0x00000004 > +#define CXL_OSC_NATIVE_HP_SUPPORT 0x00000008 > +#define CXL_OSC_SUPPORT_VALID_MASK (CXL_OSC_PORT_REG_ACCESS_SUPPORT | \ > + CXL_OSC_PORT_DEV_REG_ACCESS_SUPPORT | \ > + CXL_OSC_PER_SUPPORT | \ > + CXL_OSC_NATIVE_HP_SUPPORT) > + > +/* CXL Host Bridge _OSC: Capabilities DWORD 3: Control Field */ > +#define CXL_OSC_MEM_ERROR_CONTROL 0x00000001 > +#define CXL_OSC_CONTROL_VALID_MASK (CXL_OSC_MEM_ERROR_CONTROL) > + > int cxl_bus_prepared(struct pci_dev *pci_dev); > > #endif /* __CXL_ACPI_H__ */
On Mon, Nov 16, 2020 at 10:00 AM Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote: > > On Tue, 10 Nov 2020 21:43:49 -0800 > Ben Widawsky <ben.widawsky@intel.com> wrote: > > > From: Vishal Verma <vishal.l.verma@intel.com> > > > > Add support to advertise OS capabilities, and request OS control for CXL > > features using the ACPI _OSC mechanism. Advertise support for all > > possible CXL features, and attempt to request control too for all > > possible features. > > > > Based on a patch by Sean Kelley. > > > > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> > > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> > > I guess unsurprisingly a lot of this is cut and paste from PCIe > so can we share some of the code? > I do not see a refactoring effort for these bit being all that fruitful. The backport pressure for this driver stack I expect will be higher than most, so I'm sensitive to avoiding unnecessary core entanglements.
On Tue, Nov 17, 2020 at 12:26 AM Dan Williams <dan.j.williams@intel.com> wrote: > > On Mon, Nov 16, 2020 at 10:00 AM Jonathan Cameron > <Jonathan.Cameron@huawei.com> wrote: > > > > On Tue, 10 Nov 2020 21:43:49 -0800 > > Ben Widawsky <ben.widawsky@intel.com> wrote: > > > > > From: Vishal Verma <vishal.l.verma@intel.com> > > > > > > Add support to advertise OS capabilities, and request OS control for CXL > > > features using the ACPI _OSC mechanism. Advertise support for all > > > possible CXL features, and attempt to request control too for all > > > possible features. > > > > > > Based on a patch by Sean Kelley. > > > > > > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> > > > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> > > > > I guess unsurprisingly a lot of this is cut and paste from PCIe > > so can we share some of the code? > > > > I do not see a refactoring effort for these bit being all that > fruitful. Well, that depends on how much code duplication could be avoided this way. > The backport pressure for this driver stack I expect will be > higher than most, so I'm sensitive to avoiding unnecessary core > entanglements. If two pieces of code are based on the same underlying common code, it is immediately clear to the reader how similar to each other they are. Otherwise, they need to be carefully compared with each other to find out what the differences are and whether or not they are arbitrary or vitally important. That is essential both from the revirem perspective today and to anyone wanting to understand the given code in the future (possibly in order to modify it without breaking it). It outweighs the convenience by far IMV, with all due respect. Recall how much effort it took to combine x86 with x86_64 and why it turned out to be necessary to do that work, for one example.
On Wed, Nov 18, 2020 at 4:26 AM Rafael J. Wysocki <rafael@kernel.org> wrote: > > On Tue, Nov 17, 2020 at 12:26 AM Dan Williams <dan.j.williams@intel.com> wrote: > > > > On Mon, Nov 16, 2020 at 10:00 AM Jonathan Cameron > > <Jonathan.Cameron@huawei.com> wrote: > > > > > > On Tue, 10 Nov 2020 21:43:49 -0800 > > > Ben Widawsky <ben.widawsky@intel.com> wrote: > > > > > > > From: Vishal Verma <vishal.l.verma@intel.com> > > > > > > > > Add support to advertise OS capabilities, and request OS control for CXL > > > > features using the ACPI _OSC mechanism. Advertise support for all > > > > possible CXL features, and attempt to request control too for all > > > > possible features. > > > > > > > > Based on a patch by Sean Kelley. > > > > > > > > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> > > > > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> > > > > > > I guess unsurprisingly a lot of this is cut and paste from PCIe > > > so can we share some of the code? > > > > > > > I do not see a refactoring effort for these bit being all that > > fruitful. > > Well, that depends on how much code duplication could be avoided this way. > > > The backport pressure for this driver stack I expect will be > > higher than most, so I'm sensitive to avoiding unnecessary core > > entanglements. > > If two pieces of code are based on the same underlying common code, it > is immediately clear to the reader how similar to each other they are. > Otherwise, they need to be carefully compared with each other to find > out what the differences are and whether or not they are arbitrary or > vitally important. That is essential both from the revirem > perspective today and to anyone wanting to understand the given code > in the future (possibly in order to modify it without breaking it). > It outweighs the convenience by far IMV, with all due respect. > > Recall how much effort it took to combine x86 with x86_64 and why it > turned out to be necessary to do that work, for one example. I agree with above, but the degree of potential code sharing and refactoring for CXL is nowhere near approaching the x86_64 situation. There's also the counter example in ext3 and ext4 where a split is maintained for good reason. All I'm saying is that let's judge patches and not theory when it comes to refactoring CXL, my expectation is that those opportunities will be few and far between. CXL is a superset of PCIE functionality so it should not put much pressure on common core PCIE code to change vs incremental CXL extensions.
diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c index 26e4f73838a7..c3e2f7f6ea02 100644 --- a/drivers/cxl/acpi.c +++ b/drivers/cxl/acpi.c @@ -12,6 +12,16 @@ #include <linux/pci.h> #include "acpi.h" +/* + * TODO: These are global for now to save the OSC state. + * This works if OSC can be expected to be uniform for every ACPI0016 object. + * If that is not the case, revisit this. These need to be saved because + * relinquishing control of a previously granted capability is disallowed. + */ +static u32 cxl_osc_support_set; +static u32 cxl_osc_control_set; +static DEFINE_MUTEX(acpi_desc_lock); + static void acpi_cxl_desc_init(struct acpi_cxl_desc *acpi_desc, struct device *dev) { dev_set_drvdata(dev, acpi_desc); @@ -74,6 +84,199 @@ static struct acpi_driver acpi_cxl_driver = { }, }; +struct pci_osc_bit_struct { + u32 bit; + char *desc; +}; + +static struct pci_osc_bit_struct cxl_osc_support_bit[] = { + { CXL_OSC_PORT_REG_ACCESS_SUPPORT, "CXLPortRegAccess" }, + { CXL_OSC_PORT_DEV_REG_ACCESS_SUPPORT, "CXLPortDevRegAccess" }, + { CXL_OSC_PER_SUPPORT, "CXLProtocolErrorReporting" }, + { CXL_OSC_NATIVE_HP_SUPPORT, "CXLNativeHotPlug" }, +}; + +static struct pci_osc_bit_struct cxl_osc_control_bit[] = { + { CXL_OSC_MEM_ERROR_CONTROL, "CXLMemErrorReporting" }, +}; + +/* + * CXL 2.0 spec UUID - unusable as it PCI and CXL OSC are mixed + * static u8 cxl_osc_uuid_str[] = "68F2D50B-C469-4d8A-BD3D-941A103FD3FC"; + */ +/* New, proposed UUID for CXL-only OSC */ +static u8 cxl_osc_uuid_str[] = "A4D1629D-FF52-4888-BE96-E5CADE548DB1"; + +static void decode_osc_bits(struct device *dev, char *msg, u32 word, + struct pci_osc_bit_struct *table, int size) +{ + char buf[80]; + int i, len = 0; + struct pci_osc_bit_struct *entry; + + buf[0] = '\0'; + for (i = 0, entry = table; i < size; i++, entry++) + if (word & entry->bit) + len += scnprintf(buf + len, sizeof(buf) - len, "%s%s", + len ? " " : "", entry->desc); + + dev_info(dev, "_OSC: %s [%s]\n", msg, buf); +} + +static void decode_cxl_osc_support(struct device *dev, char *msg, u32 word) +{ + decode_osc_bits(dev, msg, word, cxl_osc_support_bit, + ARRAY_SIZE(cxl_osc_support_bit)); +} + +static void decode_cxl_osc_control(struct device *dev, char *msg, u32 word) +{ + decode_osc_bits(dev, msg, word, cxl_osc_control_bit, + ARRAY_SIZE(cxl_osc_control_bit)); +} + +static acpi_status acpi_cap_run_osc(acpi_handle handle, + const u32 *capbuf, u8 *uuid_str, u32 *retval) +{ + struct acpi_osc_context context = { + .uuid_str = uuid_str, + .rev = 1, + .cap.length = 20, + .cap.pointer = (void *)capbuf, + }; + acpi_status status; + + status = acpi_run_osc(handle, &context); + if (ACPI_SUCCESS(status)) { + *retval = *((u32 *)(context.ret.pointer + 8)); + kfree(context.ret.pointer); + } + return status; +} + +static acpi_status cxl_query_osc(acpi_handle handle, u32 support, u32 *control) +{ + acpi_status status; + u32 result, capbuf[5]; + + support &= CXL_OSC_SUPPORT_VALID_MASK; + support |= cxl_osc_support_set; + + capbuf[OSC_QUERY_DWORD] = OSC_QUERY_ENABLE; + capbuf[CXL_OSC_SUPPORT_DWORD] = support; + if (control) { + *control &= CXL_OSC_CONTROL_VALID_MASK; + capbuf[CXL_OSC_CONTROL_DWORD] = *control | cxl_osc_control_set; + } else { + /* Run _OSC query only with existing controls. */ + capbuf[CXL_OSC_CONTROL_DWORD] = cxl_osc_control_set; + } + + status = acpi_cap_run_osc(handle, capbuf, cxl_osc_uuid_str, &result); + if (ACPI_SUCCESS(status)) { + cxl_osc_support_set = support; + if (control) + *control = result; + } + return status; +} + +static acpi_status cxl_osc_advertise_support(acpi_handle handle, u32 flags) +{ + acpi_status status; + + mutex_lock(&acpi_desc_lock); + status = cxl_query_osc(handle, flags, NULL); + mutex_unlock(&acpi_desc_lock); + return status; +} + +/** + * cxl_osc_request_control - Request control of CXL root _OSC features. + * @adev: ACPI device for the PCI root bridge (or PCIe Root Complex). + * @mask: Mask of _OSC bits to request control of, place to store control mask. + * @req: Mask of _OSC bits the control of is essential to the caller. + **/ +static acpi_status cxl_osc_request_control(struct acpi_device *adev, u32 *mask, u32 req) +{ + acpi_handle handle = adev->handle; + struct device *dev = &adev->dev; + acpi_status status = AE_OK; + u32 ctrl, capbuf[5]; + + if (!mask) + return AE_BAD_PARAMETER; + + ctrl = *mask & CXL_OSC_MEM_ERROR_CONTROL; + if ((ctrl & req) != req) + return AE_TYPE; + + mutex_lock(&acpi_desc_lock); + + *mask = ctrl | cxl_osc_control_set; + /* No need to evaluate _OSC if the control was already granted. */ + if ((cxl_osc_control_set & ctrl) == ctrl) + goto out; + + /* Need to check the available controls bits before requesting them. */ + while (*mask) { + status = cxl_query_osc(handle, cxl_osc_support_set, mask); + if (ACPI_FAILURE(status)) + goto out; + if (ctrl == *mask) + break; + decode_cxl_osc_control(dev, "platform does not support", ctrl & ~(*mask)); + ctrl = *mask; + } + + if ((ctrl & req) != req) { + decode_cxl_osc_control(dev, "not requesting control; platform does not support", + req & ~(ctrl)); + status = AE_SUPPORT; + goto out; + } + + capbuf[OSC_QUERY_DWORD] = 0; + capbuf[CXL_OSC_SUPPORT_DWORD] = cxl_osc_support_set; + capbuf[CXL_OSC_CONTROL_DWORD] = ctrl; + status = acpi_cap_run_osc(handle, capbuf, cxl_osc_uuid_str, mask); + if (ACPI_SUCCESS(status)) + cxl_osc_control_set = *mask; +out: + mutex_unlock(&acpi_desc_lock); + return status; +} + +static int cxl_negotiate_osc(struct acpi_device *adev) +{ + u32 cxl_support, cxl_control, requested; + acpi_handle handle = adev->handle; + struct device *dev = &adev->dev; + acpi_status status; + + /* Declare support for everything */ + cxl_support = CXL_OSC_SUPPORT_VALID_MASK; + decode_cxl_osc_support(dev, "OS supports", cxl_support); + status = cxl_osc_advertise_support(handle, cxl_support); + if (ACPI_FAILURE(status)) { + dev_info(dev, "CXL_OSC failed (%s)\n", acpi_format_exception(status)); + return -ENXIO; + } + + /* Request control for everything */ + cxl_control = CXL_OSC_CONTROL_VALID_MASK; + requested = cxl_control; + status = cxl_osc_request_control(adev, &cxl_control, CXL_OSC_MEM_ERROR_CONTROL); + if (ACPI_SUCCESS(status)) { + decode_cxl_osc_control(dev, "OS now controls", cxl_control); + } else { + decode_cxl_osc_control(dev, "OS requested", requested); + decode_cxl_osc_control(dev, "platform willing to grant", cxl_control); + dev_info(dev, "_OSC failed (%s)\n", acpi_format_exception(status)); + } + return 0; +} + /* * If/when CXL support is defined by other platform firmware the kernel * will need a mechanism to select between the platform specific version @@ -84,6 +287,7 @@ int cxl_bus_prepared(struct pci_dev *pdev) struct acpi_device *adev; struct pci_dev *root_port; struct device *root; + int rc; root_port = pcie_find_root_port(pdev); if (!root_port) @@ -97,9 +301,11 @@ int cxl_bus_prepared(struct pci_dev *pdev) if (!adev) return -ENXIO; - /* TODO: OSC enabling */ + rc = cxl_negotiate_osc(adev); + if (rc) + dev_err(&pdev->dev, "Failed to negotiate OSC\n"); - return 0; + return rc; } EXPORT_SYMBOL_GPL(cxl_bus_prepared); diff --git a/drivers/cxl/acpi.h b/drivers/cxl/acpi.h index 011505475cc6..bf8d078e1b2a 100644 --- a/drivers/cxl/acpi.h +++ b/drivers/cxl/acpi.h @@ -10,6 +10,24 @@ struct acpi_cxl_desc { struct device *dev; }; +/* Indexes into _OSC Capabilities Buffer */ +#define CXL_OSC_SUPPORT_DWORD 1 /* DWORD 2 */ +#define CXL_OSC_CONTROL_DWORD 2 /* DWORD 3 */ + +/* CXL Host Bridge _OSC: Capabilities DWORD 2: Support Field */ +#define CXL_OSC_PORT_REG_ACCESS_SUPPORT 0x00000001 +#define CXL_OSC_PORT_DEV_REG_ACCESS_SUPPORT 0x00000002 +#define CXL_OSC_PER_SUPPORT 0x00000004 +#define CXL_OSC_NATIVE_HP_SUPPORT 0x00000008 +#define CXL_OSC_SUPPORT_VALID_MASK (CXL_OSC_PORT_REG_ACCESS_SUPPORT | \ + CXL_OSC_PORT_DEV_REG_ACCESS_SUPPORT | \ + CXL_OSC_PER_SUPPORT | \ + CXL_OSC_NATIVE_HP_SUPPORT) + +/* CXL Host Bridge _OSC: Capabilities DWORD 3: Control Field */ +#define CXL_OSC_MEM_ERROR_CONTROL 0x00000001 +#define CXL_OSC_CONTROL_VALID_MASK (CXL_OSC_MEM_ERROR_CONTROL) + int cxl_bus_prepared(struct pci_dev *pci_dev); #endif /* __CXL_ACPI_H__ */