Re: [PATCH 2/2] pci: Add PCIe driver for Rockchip Soc

From: Wenrui Li
Date: Fri May 27 2016 - 02:49:00 EST


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