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SubjectRe: [PATCH 2/2] pci: Add PCIe driver for Rockchip Soc
From
Date
Hi,

On 2016/5/24 21:03, Arnd Bergmann wrote:
> On Friday, May 20, 2016 6:29:16 PM CEST Shawn Lin wrote:
>
>> +static int rockchip_pcie_wr_own_conf(struct rockchip_pcie_port *pp,
>> + int where, int size, u32 val)
>> +{
>> + u32 tmp;
>> + int offset;
>> +
>> + offset = (where & (~0x3));
>> + tmp = readl(pp->apb_base + PCIE_RC_CONFIG_BASE + offset);
>> + if (size == 4) {
>> + writel(val, pp->apb_base + PCIE_RC_CONFIG_BASE + where);
>> + } else if (size == 2) {
>> + if (where & 0x2)
>> + tmp = ((tmp & 0xffff) | (val << 16));
>> + else
>> + tmp = ((tmp & 0xffff0000) | val);
>> +
>> + writel(tmp, pp->apb_base + PCIE_RC_CONFIG_BASE + offset);
>> + } else if (size == 1) {
>> + if ((where & 0x3) == 0)
>> + tmp = ((tmp & (~0xff)) | val);
>> + else if ((where & 0x3) == 1)
>> + tmp = ((tmp & (~0xff00)) | (val << 8));
>> + else if ((where & 0x3) == 2)
>> + tmp = ((tmp & (~0xff0000)) | (val << 16));
>> + else if ((where & 0x3) == 3)
>> + tmp = ((tmp & (~0xff000000)) | (val << 24));
>> +
>> + writel(tmp, pp->apb_base + PCIE_RC_CONFIG_BASE + offset);
>> + } else {
>> + return PCIBIOS_BAD_REGISTER_NUMBER;
>> + }
>> + return PCIBIOS_SUCCESSFUL;
>> +}
>
> Why can't you access the individual sub-word registers here?

Our soc not support byte and word write in these region. so we have to
use writel() to write these registers.

>
>> +
>> +static int rockchip_pcie_rd_other_conf(struct rockchip_pcie_port *pp,
>> + struct pci_bus *bus, u32 devfn,
>> + int where, int size, u32 *val)
>> +{
>> + u32 busdev;
>> +
>> + busdev = PCIE_ECAM_ADDR(bus->number, PCI_SLOT(devfn),
>> + PCI_FUNC(devfn), where);
>> +
>> + if (busdev & (size - 1)) {
>> + *val = 0;
>> + return PCIBIOS_BAD_REGISTER_NUMBER;
>> + }
>> +
>> + if (size == 4) {
>> + *val = readl(pp->reg_base + busdev);
>> + } else if (size == 2) {
>> + *val = readw(pp->reg_base + busdev);
>> + } else if (size == 1) {
>> + *val = readb(pp->reg_base + busdev);
>> + } else {
>> + *val = 0;
>> + return PCIBIOS_BAD_REGISTER_NUMBER;
>> + }
>> + return PCIBIOS_SUCCESSFUL;
>> +}
>> +
>
> This looks like the normal ECAM operations, you could just call those.

I read ECAM reference code, I found it not support ioremap config space
for each bus individually on 64-bit systems. Our soc is 64-bit system,
and bus0 config space base address is 0xfda00000, bus1 base address is
0xf8100000. So I think it is not normal ECAM operations, I do not know
if I have understood correctly?

>
>> + while (time_before(jiffies, timeout)) {
>> + regmap_read(port->grf, port->pcie_status, &status);
>> + if ((status & (1 << 9))) {
>> + dev_info(port->dev, "pll locked!\n");
>> + err = 0;
>> + break;
>> + }
>> + }
>
> Maybe add an msleep(1) here to avoid busy-looping?

Yeah, its a good suggestion.

>
>
>> + for (reg_no = 0; reg_no < (port->mem_size >> 20); reg_no++) {
>> + err = rockchip_pcie_prog_ob_atu(port, reg_no + 1,
>> + AXI_WRAPPER_MEM_WRITE,
>> + 20 - 1,
>> + port->mem_bus_addr +
>> + (reg_no << 20),
>> + 0);
>> + if (err) {
>> + dev_err(dev, "Program RC outbound atu failed\n");
>> + return err;
>> + }
>> + }
>
> What if there is more than one outbound memory window, e.g. prefetchable
> and non-prefetchable?
>
> Where do you set the I/O window?


Yeah, our soc support these outbound windows, we will support these
windows next patch.

>
>> + err = rockchip_pcie_prog_ib_atu(port, 2, 32 - 1, 0x0, 0);
>> + if (err) {
>> + dev_err(dev, "Program RC inbound atu failed\n");
>> + return err;
>> + }
>
> And this doesn't seem to reflect the DMA ranges.

Our soc support all the ram region use as DMA zone. SO I set all the 32
bits bypass for the inbound ATS.

>
>> +
>> + port->root_bus_nr = port->busn->start;
>> + if (IS_ENABLED(CONFIG_PCI_MSI)) {
>> + bus = pci_scan_root_bus_msi(port->dev, port->root_bus_nr,
>> + &rockchip_pcie_ops, port, &res,
>> + port->msi);
>> + } else {
>> + bus = pci_scan_root_bus(&pdev->dev, 0,
>> + &rockchip_pcie_ops, port, &res);
>
>
> PCI_MSI is selected unconditionally from Kconfig for this driver, so no
> need for the compile-time check here.

Yeah, we will delete the compile-time check in next patch.

>
>> +
>> +static int rockchip_pcie_remove(struct platform_device *pdev)
>> +{
>> + struct rockchip_pcie_port *port = platform_get_drvdata(pdev);
>> +
>> + clk_disable_unprepare(port->hclk_pcie);
>> + clk_disable_unprepare(port->aclk_perf_pcie);
>> + clk_disable_unprepare(port->aclk_pcie);
>> + clk_disable_unprepare(port->clk_pciephy_ref);
>> +
>> + return 0;
>> +}
>
> You don't seem to remove the child devices here. Have you tried unloading the module?
>

I don't seem the remove function in other pcie host driver. I think this
function could be deleted.

> Arnd
>
>
>
>
>

Best Regards
Wenrui Li

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