diff options
Diffstat (limited to 'drivers/cxl/core/pci.c')
| -rw-r--r-- | drivers/cxl/core/pci.c | 49 |
1 files changed, 42 insertions, 7 deletions
diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c index eff20e83d0a6..6c9c8d92f8f7 100644 --- a/drivers/cxl/core/pci.c +++ b/drivers/cxl/core/pci.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0-only /* Copyright(c) 2021 Intel Corporation. All rights reserved. */ +#include <linux/units.h> #include <linux/io-64-nonatomic-lo-hi.h> #include <linux/device.h> #include <linux/delay.h> @@ -620,7 +621,7 @@ void read_cdat_data(struct cxl_port *port) struct pci_dev *pdev = NULL; struct cxl_memdev *cxlmd; size_t cdat_length; - void *cdat_table; + void *cdat_table, *cdat_buf; int rc; if (is_cxl_memdev(uport)) { @@ -651,16 +652,15 @@ void read_cdat_data(struct cxl_port *port) return; } - cdat_table = devm_kzalloc(dev, cdat_length + sizeof(__le32), - GFP_KERNEL); - if (!cdat_table) + cdat_buf = devm_kzalloc(dev, cdat_length + sizeof(__le32), GFP_KERNEL); + if (!cdat_buf) return; - rc = cxl_cdat_read_table(dev, cdat_doe, cdat_table, &cdat_length); + rc = cxl_cdat_read_table(dev, cdat_doe, cdat_buf, &cdat_length); if (rc) goto err; - cdat_table = cdat_table + sizeof(__le32); + cdat_table = cdat_buf + sizeof(__le32); if (cdat_checksum(cdat_table, cdat_length)) goto err; @@ -670,7 +670,7 @@ void read_cdat_data(struct cxl_port *port) err: /* Don't leave table data allocated on error */ - devm_kfree(dev, cdat_table); + devm_kfree(dev, cdat_buf); dev_err(dev, "Failed to read/validate CDAT.\n"); } EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL); @@ -980,3 +980,38 @@ pci_ers_result_t cxl_error_detected(struct pci_dev *pdev, return PCI_ERS_RESULT_NEED_RESET; } EXPORT_SYMBOL_NS_GPL(cxl_error_detected, CXL); + +static int cxl_flit_size(struct pci_dev *pdev) +{ + if (cxl_pci_flit_256(pdev)) + return 256; + + return 68; +} + +/** + * cxl_pci_get_latency - calculate the link latency for the PCIe link + * @pdev: PCI device + * + * return: calculated latency or 0 for no latency + * + * CXL Memory Device SW Guide v1.0 2.11.4 Link latency calculation + * Link latency = LinkPropagationLatency + FlitLatency + RetimerLatency + * LinkProgationLatency is negligible, so 0 will be used + * RetimerLatency is assumed to be negligible and 0 will be used + * FlitLatency = FlitSize / LinkBandwidth + * FlitSize is defined by spec. CXL rev3.0 4.2.1. + * 68B flit is used up to 32GT/s. >32GT/s, 256B flit size is used. + * The FlitLatency is converted to picoseconds. + */ +long cxl_pci_get_latency(struct pci_dev *pdev) +{ + long bw; + + bw = pcie_link_speed_mbps(pdev); + if (bw < 0) + return 0; + bw /= BITS_PER_BYTE; + + return cxl_flit_size(pdev) * MEGA / bw; +} |