Re: [v3 5/6] PCI: rcar: Add support for rcar PCIe controller in endpoint mode

[Kishon Vijay Abraham I <kishon@ti.com>]

Hi,

On 08/01/20 9:52 PM, Lad Prabhakar wrote:
> This patch adds support for rcar PCIe controller to work in endpoint mode.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
>  drivers/pci/controller/Kconfig        |   7 +
>  drivers/pci/controller/Makefile       |   1 +
>  drivers/pci/controller/pcie-rcar-ep.c | 497 ++++++++++++++++++++++++++
>  drivers/pci/controller/pcie-rcar.h    |   6 +
>  4 files changed, 511 insertions(+)
>  create mode 100644 drivers/pci/controller/pcie-rcar-ep.c
> 
> diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
> index b022ac5678f7..69b1c778dad4 100644
> --- a/drivers/pci/controller/Kconfig
> +++ b/drivers/pci/controller/Kconfig
> @@ -61,6 +61,13 @@ config PCIE_RCAR_HOST
>  	help
>  	  Say Y here if you want PCIe controller support on R-Car SoCs in host mode.
>  
> +config PCIE_RCAR_EP
> +	bool "Renesas R-Car PCIe endpoint controller"
> +	depends on ARCH_RENESAS || COMPILE_TEST
> +	depends on PCI_ENDPOINT
> +	help
> +	  Say Y here if you want PCIe controller support on R-Car SoCs in endpoint mode.
> +
>  config PCI_HOST_COMMON
>  	bool
>  	select PCI_ECAM
> diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile
> index 69ba1dbf837b..61505b1fc66a 100644
> --- a/drivers/pci/controller/Makefile
> +++ b/drivers/pci/controller/Makefile
> @@ -8,6 +8,7 @@ obj-$(CONFIG_PCI_AARDVARK) += pci-aardvark.o
>  obj-$(CONFIG_PCI_TEGRA) += pci-tegra.o
>  obj-$(CONFIG_PCI_RCAR_GEN2) += pci-rcar-gen2.o
>  obj-$(CONFIG_PCIE_RCAR_HOST) += pcie-rcar.o pcie-rcar-host.o
> +obj-$(CONFIG_PCIE_RCAR_EP) += pcie-rcar.o pcie-rcar-ep.o
>  obj-$(CONFIG_PCI_HOST_COMMON) += pci-host-common.o
>  obj-$(CONFIG_PCI_HOST_GENERIC) += pci-host-generic.o
>  obj-$(CONFIG_PCIE_XILINX) += pcie-xilinx.o
> diff --git a/drivers/pci/controller/pcie-rcar-ep.c b/drivers/pci/controller/pcie-rcar-ep.c
> new file mode 100644
> index 000000000000..40cd2aad8c3c
> --- /dev/null
> +++ b/drivers/pci/controller/pcie-rcar-ep.c
> @@ -0,0 +1,497 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * PCIe endpoint driver for Renesas R-Car SoCs
> + *  Copyright (c) 2020 Renesas Electronics Europe GmbH
> + *
> + * Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_pci.h>
> +#include <linux/of_platform.h>
> +#include <linux/pci.h>
> +#include <linux/pci-epc.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +
> +#include "pcie-rcar.h"
> +
> +#define MAX_NR_INBOUND_MAPS	6
> +#define MAX_NR_OUTBOUND_MAPS	4
> +
> +/* Structure representing the PCIe interface */
> +struct rcar_pcie {
> +	phys_addr_t		*ob_addr;
> +	struct pci_epc_mem_window *ob_window;
> +	struct pci_epc		*epc;
> +	struct device		*dev;
> +	void __iomem		*base;
> +	u8			max_functions;
> +	unsigned int		bar_to_atu[MAX_NR_INBOUND_MAPS];
> +	unsigned long		*ib_window_map;
> +	u32			num_ib_windows;
> +	u32			num_ob_windows;
> +};
> +
> +static void rcar_pcie_ep_hw_init(struct rcar_pcie *pcie)
> +{
> +	u32 val;
> +
> +	rcar_pci_write_reg(pcie->base, 0, PCIETCTLR);
> +
> +	/* Set endpoint mode */
> +	rcar_pci_write_reg(pcie->base, 0, PCIEMSR);
> +
> +	/* Initialize default capabilities. */
> +	rcar_rmw32(pcie->base, REXPCAP(0), 0xff, PCI_CAP_ID_EXP);
> +	rcar_rmw32(pcie->base, REXPCAP(PCI_EXP_FLAGS),
> +		   PCI_EXP_FLAGS_TYPE, PCI_EXP_TYPE_ENDPOINT << 4);
> +	rcar_rmw32(pcie->base, RCONF(PCI_HEADER_TYPE), 0x7f,
> +		   PCI_HEADER_TYPE_NORMAL);
> +
> +	/* Write out the physical slot number = 0 */
> +	rcar_rmw32(pcie->base, REXPCAP(PCI_EXP_SLTCAP), PCI_EXP_SLTCAP_PSN, 0);
> +
> +	val = rcar_pci_read_reg(pcie->base, EXPCAP(1));
> +	/* device supports fixed 128 bytes MPSS */
> +	val &= ~GENMASK(2, 0);
> +	/* L1 to L0 transition latency no time limit */
> +	val |= GENMASK(11, 9);
> +	/* L0s to L0 transistion no time limit */
> +	val |= GENMASK(8, 6);
> +	rcar_pci_write_reg(pcie->base, val, EXPCAP(1));
> +
> +	val = rcar_pci_read_reg(pcie->base, EXPCAP(2));
> +	/* read requests size 128 bytes */
> +	val &= ~GENMASK(14, 12);
> +	/* payload size 128 bytes */
> +	val &= ~GENMASK(7, 5);
> +	/* disable relaxed ordering transaction */
> +	val &= ~BIT(4);
> +	rcar_pci_write_reg(pcie->base, val, EXPCAP(2));
> +
> +	val = rcar_pci_read_reg(pcie->base, EXPCAP(4));
> +	/* disable ASPM control */
> +	val &= ~GENMASK(1, 0);
> +	rcar_pci_write_reg(pcie->base, val, EXPCAP(4));
> +
> +	/* Set target link speed to 5.0 GT/s */
> +	rcar_rmw32(pcie->base, EXPCAP(12), PCI_EXP_LNKSTA_CLS,
> +		   PCI_EXP_LNKSTA_CLS_5_0GB);
> +
> +	/* Set the completion timer timeout to the maximum 50ms. */
> +	rcar_rmw32(pcie->base, TLCTLR + 1, 0x3f, 50);
> +
> +	/* Terminate list of capabilities (Next Capability Offset=0) */
> +	rcar_rmw32(pcie->base, RVCCAP(0), 0xfff00000, 0);
> +
> +	/* flush modifications */
> +	wmb();
> +}
> +
> +static int rcar_pcie_parse_outbound_ranges(struct rcar_pcie *pcie,
> +					   struct platform_device *pdev)
> +{
> +	char outbound_name[10];
> +	struct resource *res;
> +	unsigned int i = 0;
> +
> +	pcie->num_ob_windows = 0;
> +	for (i = 0; i < MAX_NR_OUTBOUND_MAPS; i++) {
> +		sprintf(outbound_name, "memory%u", i);
> +		res = platform_get_resource_byname(pdev,
> +						   IORESOURCE_MEM,
> +						   outbound_name);
> +		if (!res) {
> +			dev_err(pcie->dev, "missing outbound window %u\n", i);
> +			return -EINVAL;
> +		}
> +		if (!devm_request_mem_region(&pdev->dev, res->start,
> +					     resource_size(res),
> +					     outbound_name)) {
> +			dev_err(pcie->dev, "Cannot request memory region %s.\n",
> +				outbound_name);
> +			return -EIO;
> +		}
> +
> +		pcie->ob_window[i].phys_base = res->start;
> +		pcie->ob_window[i].size = resource_size(res);
> +		/* controller doesn't support multiple allocation
> +		 * from same window, so set page_size to window size
> +		 */
> +		pcie->ob_window[i].page_size = resource_size(res);

I would prefer the page_size comes from device tree. I'm also thinking
if we should add a standard binding for specifying the outbound memory
regions. Rob, what do you think?

Thanks
Kishon