dma: Add Synopsys eDMA IP PCIe glue-logic
RFC 4/6 dma: Add Synopsys eDMA IP PCIe glue-logic
Quoted 23 lines · Gustavo Pimentel
Synopsys eDMA IP is normally distributed along with Synopsys PCIe EndPoint IP (depends of the use and licensing agreement).
This IP requires some basic configurations, such as:
- eDMA registers BAR
- eDMA registers offset
- eDMA linked list BAR
- eDMA linked list offset
- eDMA linked list size
- eDMA version
- eDMA modeAs a working example, PCIe glue-logic will attach to a Synopsys PCIe EndPoint IP prototype kit (Vendor ID =
0x16c3, Device ID =0xedda), which has built-in an eDMA IP with this default configuration:
- eDMA registers BAR = 0
- eDMA registers offset =0x1000(4 Kbytes)
- eDMA linked list BAR = 2
- eDMA linked list offset =0x0(0 Kbytes)
- eDMA linked list size =0x20000(128 Kbytes)
- eDMA version = 0
- eDMA mode =EDMA_MODE_UNROLL
Quoted 5 lines
This driver can be compile as built-in or external module in kernel.
To enable this driver just select
DW_EDMA_PCIEoption in kernel configuration, however it requires and selects automaticallyDW_EDMAoption too.
It seems this driver somehow written as a copy-paste of existing pieces w/o good reasons to do such.
Review
Quoted 8 lines
(quoted diff) +8
-0+enum dw_edma_pcie_bar { + BAR_0, + BAR_1, + BAR_2, + BAR_3, + BAR_4, + BAR_5 +};
Why do you need this at all?
Review
Quoted 12 lines
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-0+static const struct dw_edma_pcie_data snps_edda_data = { + // eDMA registers location + .regs_bar = BAR_0, + .regs_off = 0x1000, // 4 KBytes + // eDMA memory linked list location + .ll_bar = BAR_2, + .ll_off = 0, // 0 KBytes + .ll_sz = 0x20000, // 128 KBytes + // Other + .version = 0, + .mode = EDMA_MODE_UNROLL, +};
Huh? Isn't this
Quoted 31 lines
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-0+ +static int dw_edma_pcie_probe(struct pci_dev *pdev, + const struct pci_device_id *pid) +{ + const struct dw_edma_pcie_data *pdata = (void *)pid->driver_data; + struct device *dev = &pdev->dev; + struct dw_edma_chip *chip; + struct dw_edma *dw; + void __iomem *reg; + int err, irq = -1; + u32 addr_hi, addr_lo; + u16 flags; + u8 cap_off; + + if (!pdata) { + dev_err(dev, "%s missing data struture\n", + pci_name(pdev)); + return -EFAULT; + } + + err = pcim_enable_device(pdev); + if (err) { + dev_err(dev, "%s enabling device failed\n", + pci_name(pdev)); + return err; + } + + err = pcim_iomap_regions(pdev, 1 << pdata->regs_bar, pci_name(pdev)); + if (err) { + dev_err(dev, "%s eDMA register BAR I/O memory remapping failed\n",
Review
Quoted 10 lines
(quoted diff) +10
-0+ pci_name(pdev)); + return err; + } + + err = pcim_iomap_regions(pdev, 1 << pdata->ll_bar, pci_name(pdev)); + if (err) { + dev_err(dev, "%s eDMA linked list BAR I/O remapping failed\n", + pci_name(pdev)); + return err; + }
This could be done in one call.
Review
Quoted 10 lines
(quoted diff) +9
-0+ + pci_set_master(pdev); + + err = pci_try_set_mwi(pdev); + if (err) { + dev_err(dev, "%s DMA memory write invalidate\n", + pci_name(pdev)); + return err; + }
Are you sure you need this?
Quoted 50 lines
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-0+ + err = pci_set_dma_mask(pdev, DMA_BIT_MASK(32)); + if (err) { + dev_err(dev, "%s DMA mask set failed\n", + pci_name(pdev)); + return err; + } + + err = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32)); + if (err) { + dev_err(dev, "%s consistent DMA mask set failed\n", + pci_name(pdev)); + return err; + } + + chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + dw = devm_kzalloc(&pdev->dev, sizeof(*dw), GFP_KERNEL); + if (!dw) + return -ENOMEM; + + irq = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI | PCI_IRQ_MSIX); + if (irq < 0) { + dev_err(dev, "%s failed to alloc IRQ vector\n", + pci_name(pdev)); + return -EPERM; + } + + chip->dw = dw; + chip->dev = dev; + chip->id = pdev->devfn; + chip->irq = pdev->irq; + + dw->regs = pcim_iomap_table(pdev)[pdata->regs_bar]; + dw->regs += pdata->regs_off; + + dw->va_ll = pcim_iomap_table(pdev)[pdata->ll_bar]; + dw->va_ll += pdata->ll_off; + dw->pa_ll = pdev->resource[pdata->ll_bar].start; + dw->pa_ll += pdata->ll_off; + dw->ll_sz = pdata->ll_sz; + + dw->msi_addr = 0; + dw->msi_data = 0; + + dw->version = pdata->version; + dw->mode = pdata->mode; +
Review
Quoted 10 lines
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-0+ dev_info(dev, "Version:\t%u\n", dw->version); + + dev_info(dev, "Mode:\t%s\n", + dw->mode == EDMA_MODE_LEGACY ? "Legacy" : "Unroll"); + + dev_info(dev, "Registers:\tBAR=%u, off=0x%.16llx B, addr=0x%.8lx\n", + pdata->regs_bar, pdata->regs_off, + (unsigned long) dw->regs);
Oh, no, don't do casting when printing something. In only rare cases it's needed, not here.
Review
Quoted 6 lines
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-0+ + dev_info(dev, + "L. List:\tBAR=%u, off=0x%.16llx B, sz=0x%.8x B, vaddr=0x%.8lx, paddr=0x%.8lx", + pdata->ll_bar, pdata->ll_off, pdata->ll_sz, + (unsigned long) dw->va_ll, + (unsigned long) dw->pa_ll);
This is noise, either remove or move to dbg level.
Quoted 49 lines
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-0+ if (pdev->msi_cap && pdev->msi_enabled) { + cap_off = pdev->msi_cap + PCI_MSI_FLAGS; + pci_read_config_word(pdev, cap_off, &flags); + if (flags & PCI_MSI_FLAGS_ENABLE) { + cap_off = pdev->msi_cap + PCI_MSI_ADDRESS_LO; + pci_read_config_dword(pdev, cap_off, &addr_lo); + + if (flags & PCI_MSI_FLAGS_64BIT) { + cap_off = pdev->msi_cap + PCI_MSI_ADDRESS_HI; + pci_read_config_dword(pdev, cap_off, &addr_hi); + cap_off = pdev->msi_cap + PCI_MSI_DATA_64; + } else { + addr_hi = 0; + cap_off = pdev->msi_cap + PCI_MSI_DATA_32; + } + + dw->msi_addr = addr_hi; + dw->msi_addr <<= 32; + dw->msi_addr |= addr_lo; + + pci_read_config_dword(pdev, cap_off, &(dw->msi_data)); + dw->msi_data &= 0xffff; + + dev_info(dev, + "MSI:\t\taddr=0x%.16llx, data=0x%.8x, nr=%d\n", + dw->msi_addr, dw->msi_data, pdev->irq); + } + } + + if (pdev->msix_cap && pdev->msix_enabled) { + u32 offset; + u8 bir; + + cap_off = pdev->msix_cap + PCI_MSIX_FLAGS; + pci_read_config_word(pdev, cap_off, &flags); + + if (flags & PCI_MSIX_FLAGS_ENABLE) { + cap_off = pdev->msix_cap + PCI_MSIX_TABLE; + pci_read_config_dword(pdev, cap_off, &offset); + + bir = offset & PCI_MSIX_TABLE_BIR; + offset &= PCI_MSIX_TABLE_OFFSET; + + reg = pcim_iomap_table(pdev)[bir]; + reg += offset; + + addr_lo = readl(reg + PCI_MSIX_ENTRY_LOWER_ADDR); + addr_hi = readl(reg + PCI_MSIX_ENTRY_UPPER_ADDR); + dw->msi_addr = addr_hi;
Review
Quoted 10 lines
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-0+ dw->msi_addr <<= 32; + dw->msi_addr |= addr_lo; + + dw->msi_data = readl(reg + PCI_MSIX_ENTRY_DATA); + + dev_info(dev, + "MSI-X:\taddr=0x%.16llx, data=0x%.8x, nr=%d\n", + dw->msi_addr, dw->msi_data, pdev->irq); + } + }
What is this? Why?
Review
Quoted 2 lines
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-0+ + if (!pdev->msi_enabled && !pdev->msix_enabled) {
There is a helper from PCI core for this.
Quoted 19 lines
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-0+ dev_err(dev, "%s enable interrupt failed\n", + pci_name(pdev)); + return -EPERM; + } + + err = dw_edma_probe(chip); + if (err) { + dev_err(dev, "%s eDMA probe failed\n", + pci_name(pdev)); + return err; + } + + pci_set_drvdata(pdev, chip); + + dev_info(dev, "DesignWare eDMA PCIe driver loaded completely\n"); + + return 0; +} +
Review
Quoted 10 lines
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-0+static void dw_edma_pcie_remove(struct pci_dev *pdev) +{ + struct dw_edma_chip *chip = pci_get_drvdata(pdev); + struct device *dev = &pdev->dev; + int err; + + err = dw_edma_remove(chip); + if (err) { + dev_warn(dev, "%s can't remove device properly: %d\n", + pci_name(pdev), err);
dev_warn + dev_name ?! Have you tried to see what would be the output?
Review
Quoted 9 lines
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-0+ } + + pci_free_irq_vectors(pdev); + + dev_info(dev, "DesignWare eDMA PCIe driver unloaded completely\n"); +} + +#ifdef CONFIG_PM_SLEEP
You can use __maybe_unused instead of this.
Quoted 1 line
+#endif /*
CONFIG_PM_SLEEP*/