在最新的kennel 5.12.5终于看到对NVMe 1.4协议的CMB支持了，喜大普奔！散花散花！
NVMe 1.4协议的CMB功能变化太大了，增加了CMBS，CRE，CMBMSC，CMBSTS。看起来终于像一个像样的功能了。
这次驱动更新终于更新到这一块了，不枉我天天在我的dnvme驱动上修修补补。。。
PMR也抓紧跟上。。。
static void nvme_map_cmb(struct nvme_dev *dev)
{
u64 size, offset;
resource_size_t bar_size;
struct pci_dev *pdev = to_pci_dev(dev->dev);
int bar;
if (dev->cmb_size)
return;
if (NVME_CAP_CMBS(dev->ctrl.cap))
writel(NVME_CMBMSC_CRE, dev->bar + NVME_REG_CMBMSC);
dev->cmbsz = readl(dev->bar + NVME_REG_CMBSZ);
if (!dev->cmbsz)
return;
dev->cmbloc = readl(dev->bar + NVME_REG_CMBLOC);
size = nvme_cmb_size_unit(dev) * nvme_cmb_size(dev);
offset = nvme_cmb_size_unit(dev) * NVME_CMB_OFST(dev->cmbloc);
bar = NVME_CMB_BIR(dev->cmbloc);
bar_size = pci_resource_len(pdev, bar);
if (offset > bar_size)
return;
/*
* Tell the controller about the host side address mapping the CMB,
* and enable CMB decoding for the NVMe 1.4+ scheme:
*/
if (NVME_CAP_CMBS(dev->ctrl.cap)) {
hi_lo_writeq(NVME_CMBMSC_CRE | NVME_CMBMSC_CMSE |
(pci_bus_address(pdev, bar) + offset),
dev->bar + NVME_REG_CMBMSC);
}
/*
* Controllers may support a CMB size larger than their BAR,
* for example, due to being behind a bridge. Reduce the CMB to
* the reported size of the BAR
*/
if (size > bar_size - offset)
size = bar_size - offset;
if (pci_p2pdma_add_resource(pdev, bar, size, offset)) {
dev_warn(dev->ctrl.device,
"failed to register the CMB\n");
return;
}
dev->cmb_size = size;
dev->cmb_use_sqes = use_cmb_sqes && (dev->cmbsz & NVME_CMBSZ_SQS);
if ((dev->cmbsz & (NVME_CMBSZ_WDS | NVME_CMBSZ_RDS)) ==
(NVME_CMBSZ_WDS | NVME_CMBSZ_RDS))
pci_p2pmem_publish(pdev, true);
if (sysfs_add_file_to_group(&dev->ctrl.device->kobj,
&dev_attr_cmb.attr, NULL))
dev_warn(dev->ctrl.device,
"failed to add sysfs attribute for CMB\n");
}