Re: [PATCH 3/6] pci:host: Add Altera PCIe host controller driver

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On Tue, Jul 28, 2015 at 5:45 AM, Ley Foon Tan <lftan@xxxxxxxxxx> wrote:
> This patch adds the Altera PCIe host controller driver.
>
> Signed-off-by: Ley Foon Tan <lftan@xxxxxxxxxx>
> ---
>  drivers/pci/host/Kconfig       |   9 +
>  drivers/pci/host/Makefile      |   1 +
>  drivers/pci/host/pcie-altera.c | 576 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 586 insertions(+)
>  create mode 100644 drivers/pci/host/pcie-altera.c
>
> diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
> index 675c2d1..af19039 100644
> --- a/drivers/pci/host/Kconfig
> +++ b/drivers/pci/host/Kconfig
> @@ -145,4 +145,13 @@ config PCIE_IPROC_BCMA
>           Say Y here if you want to use the Broadcom iProc PCIe controller
>           through the BCMA bus interface
>
> +config PCIE_ALTERA
> +       bool "Altera PCIe controller"
> +       depends on ARCH_SOCFPGA
> +       depends on OF
> +       select PCI_MSI_IRQ_DOMAIN if PCI_MSI
> +       help
> +         Say Y here if you want to enable PCIe controller support for Altera
> +         SoCFPGA family of SoCs.
> +
>  endmenu
> diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
> index 140d66f..6954f76 100644
> --- a/drivers/pci/host/Makefile
> +++ b/drivers/pci/host/Makefile
> @@ -17,3 +17,4 @@ obj-$(CONFIG_PCI_VERSATILE) += pci-versatile.o
>  obj-$(CONFIG_PCIE_IPROC) += pcie-iproc.o
>  obj-$(CONFIG_PCIE_IPROC_PLATFORM) += pcie-iproc-platform.o
>  obj-$(CONFIG_PCIE_IPROC_BCMA) += pcie-iproc-bcma.o
> +obj-$(CONFIG_PCIE_ALTERA) += pcie-altera.o
> diff --git a/drivers/pci/host/pcie-altera.c b/drivers/pci/host/pcie-altera.c
> new file mode 100644
> index 0000000..afa64e9
> --- /dev/null
> +++ b/drivers/pci/host/pcie-altera.c
> @@ -0,0 +1,576 @@
> +/*
> + * Copyright Altera Corporation (C) 2013-2015. All rights reserved
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_pci.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#define A2P_ADDR_MAP_LO0               0x1000
> +#define A2P_ADDR_MAP_HI0               0x1004
> +#define RP_TX_REG0                     0x2000
> +#define RP_TX_REG1                     0x2004
> +#define RP_TX_CNTRL                    0x2008
> +#define RP_TX_EOP                      0x2
> +#define RP_TX_SOP                      0x1
> +#define RP_RXCPL_STATUS                0x2010
> +#define RP_RXCPL_EOP                   0x2
> +#define RP_RXCPL_SOP                   0x1
> +#define RP_RXCPL_REG0                  0x2014
> +#define RP_RXCPL_REG1                  0x2018
> +#define P2A_INT_STATUS                 0x3060
> +#define P2A_INT_STS_ALL                        0xF
> +#define P2A_INT_ENABLE                 0x3070
> +#define P2A_INT_ENA_ALL                        0xF
> +#define RP_LTSSM                       0x3C64
> +#define LTSSM_L0                       0xF
> +
> +/* TLP configuration type 0 and 1 */
> +#define TLP_FMTTYPE_CFGRD0             0x04    /* Configuration Read Type 0 */
> +#define TLP_FMTTYPE_CFGWR0             0x44    /* Configuration Write Type 0 */
> +#define TLP_FMTTYPE_CFGRD1             0x05    /* Configuration Read Type 1 */
> +#define TLP_FMTTYPE_CFGWR1             0x45    /* Configuration Write Type 1 */
> +#define TLP_PAYLOAD_SIZE               0x01
> +#define TLP_READ_TAG                   0x1D
> +#define TLP_WRITE_TAG                  0x10
> +#define TLP_CFG_DW0(fmttype)           (((fmttype) << 24) | TLP_PAYLOAD_SIZE)
> +#define TLP_CFG_DW1(reqid, tag)                (((reqid) << 16) | (tag << 8) | 0xF)
> +#define TLP_CFG_DW2(bus, devfn, offset)        \
> +                               (((bus) << 24) | ((devfn) << 16) | (offset))
> +#define TLP_REQ_ID(bus, devfn)         (((bus) << 8) | (devfn))
> +#define TLP_COMPL_STATUS(hdr)          (((hdr) & 0xE0) >> 13)
> +#define TLP_HDR_SIZE                   3
> +#define TLP_LOOP                       10
> +
> +#define INTX_NUM               4
> +
> +/* Address translation table entry size */
> +#define ATT_ENTRY_SIZE         8
> +
> +#define DWORD_MASK             3
> +
> +struct altera_pcie {
> +       struct platform_device  *pdev;
> +       struct resource         *txs;
> +       void __iomem            *cra_base;
> +       int                     hwirq;
> +       u8                      root_bus_nr;
> +       struct irq_domain               *irq_domain;
> +       struct resource         bus_range;
> +       struct list_head                resources;
> +};
> +
> +struct tlp_rp_regpair_t {
> +       u32 ctrl;
> +       u32 reg0;
> +       u32 reg1;
> +};
> +
> +static inline struct altera_pcie *sys_to_pcie(struct pci_sys_data *sys)
> +{
> +       return sys->private_data;
> +}
> +
> +static void altera_pcie_retrain(struct pci_dev *dev)
> +{
> +       u16 linkcap, linkstat;
> +
> +       /*
> +        * Set the retrain bit if the PCIe rootport support > 2.5GB/s, but
> +        * current speed is 2.5 GB/s.
> +        */
> +       pcie_capability_read_word(dev, PCI_EXP_LNKCAP, &linkcap);
> +
> +       if ((linkcap & PCI_EXP_LNKCAP_SLS) <= PCI_EXP_LNKCAP_SLS_2_5GB)
> +               return;
> +
> +       pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &linkstat);
> +       if ((linkstat & PCI_EXP_LNKSTA_CLS) == PCI_EXP_LNKSTA_CLS_2_5GB)
> +               pcie_capability_set_word(dev, PCI_EXP_LNKCTL,
> +                                       PCI_EXP_LNKCTL_RL);
> +
> +}
> +DECLARE_PCI_FIXUP_EARLY(PCI_ANY_ID, PCI_ANY_ID, altera_pcie_retrain);
> +
> +static inline void cra_writel(struct altera_pcie *pcie, u32 value, u32 reg)
> +{
> +       writel(value, pcie->cra_base + reg);
> +}
> +
> +static inline u32 cra_readl(struct altera_pcie *pcie, u32 reg)
> +{
> +       return readl(pcie->cra_base + reg);
> +}
> +
> +static void tlp_read_rx(struct altera_pcie *pcie,
> +                       struct tlp_rp_regpair_t *tlp_rp_regdata)
> +{
> +       tlp_rp_regdata->ctrl = cra_readl(pcie, RP_RXCPL_STATUS);
> +       tlp_rp_regdata->reg0 = cra_readl(pcie, RP_RXCPL_REG0);
> +       tlp_rp_regdata->reg1 = cra_readl(pcie, RP_RXCPL_REG1);
> +}
> +
> +static void tlp_write_tx(struct altera_pcie *pcie,
> +                       struct tlp_rp_regpair_t *tlp_rp_regdata)
> +{
> +       cra_writel(pcie, tlp_rp_regdata->reg0, RP_TX_REG0);
> +       cra_writel(pcie, tlp_rp_regdata->reg1, RP_TX_REG1);
> +       cra_writel(pcie, tlp_rp_regdata->ctrl, RP_TX_CNTRL);
> +}
> +
> +static bool altera_pcie_link_is_up(struct altera_pcie *pcie)
> +{
> +       return !!(cra_readl(pcie, RP_LTSSM) & LTSSM_L0);
> +}
> +
> +static bool altera_pcie_valid_config(struct altera_pcie *pcie,
> +                               struct pci_bus *bus, int dev)
> +{
> +       /* If there is no link, then there is no device */
> +       if (bus->number != pcie->root_bus_nr) {
> +               if (!altera_pcie_link_is_up(pcie))
> +                       return false;
> +       }
> +
> +       /* access only one slot on each root port */
> +       if (bus->number == pcie->root_bus_nr && dev > 0)
> +               return false;
> +
> +       /*
> +        * Do not read more than one device on the bus directly attached
> +        * to RC.
> +        */
> +       if (bus->primary == pcie->root_bus_nr && dev > 0)
> +               return false;
> +
> +        return true;
> +}
> +
> +static int tlp_read_packet(struct altera_pcie *pcie, u32 *value)
> +{
> +       u8 loop;
> +       struct tlp_rp_regpair_t tlp_rp_regdata;
> +
> +       for (loop = TLP_LOOP; loop > 0; loop--) {
> +
> +               tlp_read_rx(pcie, &tlp_rp_regdata);
> +
> +               if (tlp_rp_regdata.ctrl & RP_RXCPL_EOP) {
> +
> +                       if (value)
> +                               *value = tlp_rp_regdata.reg0;
> +
> +                       return PCIBIOS_SUCCESSFUL;
> +               }
> +       }
> +
> +       return -ENOENT;
> +}
> +
> +static void tlp_write_packet(struct altera_pcie *pcie, u32 *headers, u32 data)
> +{
> +       struct tlp_rp_regpair_t tlp_rp_regdata;
> +
> +       tlp_rp_regdata.reg0 = headers[0];
> +       tlp_rp_regdata.reg1 = headers[1];
> +       tlp_rp_regdata.ctrl = RP_TX_SOP;
> +       tlp_write_tx(pcie, &tlp_rp_regdata);
> +
> +       tlp_rp_regdata.reg0 = headers[2];
> +       tlp_rp_regdata.reg1 = data;
> +       tlp_rp_regdata.ctrl = RP_TX_EOP;
> +       tlp_write_tx(pcie, &tlp_rp_regdata);
> +}
> +
> +static int tlp_cfg_dword_read(struct altera_pcie *pcie, u8 bus, u32 devfn,
> +                             int where, u32 *value)
> +{
> +       int ret;
> +       u32 headers[TLP_HDR_SIZE];
> +
> +       if (bus == pcie->root_bus_nr)
> +               headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGRD0);
> +       else
> +               headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGRD1);
> +
> +       headers[1] = TLP_CFG_DW1(TLP_REQ_ID(pcie->root_bus_nr, devfn),
> +                                       TLP_READ_TAG);
> +       headers[2] = TLP_CFG_DW2(bus, devfn, where);
> +
> +       tlp_write_packet(pcie, headers, 0);
> +
> +       ret = tlp_read_packet(pcie, value);
> +       if (ret)
> +               *value = ~0UL;  /* return 0xFFFFFFFF if error */
> +
> +       return ret;
> +}
> +
> +static int tlp_cfg_dword_write(struct altera_pcie *pcie, u8 bus, u32 devfn,
> +                              int where, u32 value)
> +{
> +       u32 headers[TLP_HDR_SIZE];
> +
> +       if (bus == pcie->root_bus_nr)
> +               headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGWR0);
> +       else
> +               headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGWR1);
> +
> +       headers[1] = TLP_CFG_DW1(TLP_REQ_ID(pcie->root_bus_nr, devfn),
> +                                       TLP_WRITE_TAG);
> +       headers[2] = TLP_CFG_DW2(bus, devfn, where);
> +
> +       tlp_write_packet(pcie, headers, value);
> +
> +       tlp_read_packet(pcie, NULL);
> +
> +       /* Keep an eye out for changes to the root bus number */
> +       if ((bus == pcie->root_bus_nr) && (where == PCI_PRIMARY_BUS))
> +               pcie->root_bus_nr = (u8)(value);
> +
> +       return PCIBIOS_SUCCESSFUL;
> +}
> +
> +static int altera_pcie_cfg_read(struct pci_bus *bus, unsigned int devfn,
> +                              int where, int size, u32 *value)
> +{
> +       struct altera_pcie *pcie = sys_to_pcie(bus->sysdata);
> +       int ret;
> +
> +       if (!altera_pcie_valid_config(pcie, bus, PCI_SLOT(devfn))) {
> +               *value = ~0UL;
> +               return PCIBIOS_DEVICE_NOT_FOUND;
> +       }
> +
> +       ret = tlp_cfg_dword_read(pcie, bus->number, devfn,
> +               (where & ~DWORD_MASK), value);
> +       if (ret != PCIBIOS_SUCCESSFUL)
> +               return ret;
> +
> +       if (size == 1)
> +               *value = (*value >> (8 * (where & 0x3))) & 0xff;
> +       else if (size == 2)
> +               *value = (*value >> (8 * (where & 0x2))) & 0xffff;
> +
> +       return PCIBIOS_SUCCESSFUL;
> +}
> +
> +static int altera_pcie_cfg_write(struct pci_bus *bus, unsigned int devfn,
> +                               int where, int size, u32 value)
> +{
> +       struct altera_pcie *pcie = sys_to_pcie(bus->sysdata);
> +       u32 data32 = value;
> +       u32 shift = 8 * (where & 3);
> +       int ret;
> +
> +       if (!altera_pcie_valid_config(pcie, bus, PCI_SLOT(devfn)))
> +               return PCIBIOS_DEVICE_NOT_FOUND;
> +
> +       /* write partial */
> +       if (size != sizeof(u32)) {
> +               ret = tlp_cfg_dword_read(pcie, bus->number, devfn,
> +                       where & ~DWORD_MASK, &data32);
> +               if (ret)
> +                       return ret;
> +
> +               if (size == 2)
> +                       data32 = (data32 & ~(0xffff << shift)) |
> +                                       ((value & 0xffff) << shift);
> +                else if (size == 1)
> +                       data32 = (data32 & ~(0xff << shift)) |
> +                                       ((value & 0xff) << shift);
> +       }
> +
> +       return tlp_cfg_dword_write(pcie, bus->number, devfn,
> +               (where & ~DWORD_MASK), data32);
> +}
> +
> +static struct pci_ops altera_pcie_ops = {
> +       .read = altera_pcie_cfg_read,
> +       .write = altera_pcie_cfg_write,
> +};
> +
> +static int altera_pcie_setup(int nr, struct pci_sys_data *sys)
> +{
> +       struct altera_pcie *pcie = sys->private_data;
> +
> +       list_splice_init(&pcie->resources, &sys->resources);
> +
> +       return 1;
> +}
> +
> +static int altera_pcie_map_irq(const struct pci_dev *pdev, u8 slot, u8 pin)
> +{
> +       struct altera_pcie *pcie = sys_to_pcie(pdev->bus->sysdata);
> +       int irq;
> +
> +       irq = of_irq_parse_and_map_pci(pdev, slot, pin);
> +
> +       if (!irq)
> +               irq = pcie->hwirq;
> +
> +       return irq;
> +}

This should not be needed as the core code should take care of this.

> +
> +static struct pci_bus *altera_pcie_scan_bus(int nr, struct pci_sys_data *sys)
> +{
> +       struct altera_pcie *pcie = sys_to_pcie(sys);
> +       struct pci_bus *bus;
> +
> +       pcie->root_bus_nr = sys->busnr;
> +       bus = pci_scan_root_bus(&pcie->pdev->dev, sys->busnr, &altera_pcie_ops,
> +                               sys, &sys->resources);
> +
> +       return bus;
> +}
> +
> +static struct hw_pci altera_pcie_hw __initdata = {
> +#ifdef CONFIG_PCI_DOMAINS
> +       .domain                 = 0,
> +#endif
> +       .nr_controllers         = 1,
> +       .ops                    = &altera_pcie_ops,
> +       .setup                  = altera_pcie_setup,
> +       .map_irq                        = altera_pcie_map_irq,
> +       .scan                   = altera_pcie_scan_bus,

You should be able to only have an empty hw_pci struct now.

> +};
> +
> +static int altera_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
> +                               irq_hw_number_t hwirq)
> +{
> +       irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
> +       irq_set_chip_data(irq, domain->host_data);
> +       set_irq_flags(irq, IRQF_VALID);
> +
> +       return 0;
> +}
> +
> +static const struct irq_domain_ops intx_domain_ops = {
> +       .map = altera_pcie_intx_map,
> +};
> +
> +static irqreturn_t altera_pcie_isr(int irq, void *arg)
> +{
> +       struct altera_pcie *pcie = arg;
> +       u32 status, i;
> +
> +       status = cra_readl(pcie, P2A_INT_STATUS) & P2A_INT_STS_ALL;
> +
> +       /* clear interrupts */
> +       cra_writel(pcie, status, P2A_INT_STATUS);
> +
> +       for (i = 0; i < INTX_NUM; i++) {
> +               if (status & (1 << i))
> +                       generic_handle_irq(irq_find_mapping(pcie->irq_domain,
> +                                                       i + 1));
> +       }
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static void altera_pcie_release_of_pci_ranges(struct altera_pcie *pcie)
> +{
> +       pci_free_resource_list(&pcie->resources);
> +}
> +
> +static int altera_pcie_parse_request_of_pci_ranges(struct altera_pcie *pcie)
> +{
> +       int err, res_valid = 0;
> +       struct device *dev = &pcie->pdev->dev;
> +       struct device_node *np = dev->of_node;
> +       resource_size_t iobase;
> +       struct resource_entry *win;
> +       int offset = 0;
> +
> +       err = of_pci_get_host_bridge_resources(np, 0, 0xff, &pcie->resources,
> +                                              &iobase);
> +       if (err)
> +               return err;
> +
> +       resource_list_for_each_entry(win, &pcie->resources) {
> +               struct resource *parent, *res = win->res;
> +
> +               switch (resource_type(res)) {
> +               case IORESOURCE_MEM:
> +                       parent = &iomem_resource;
> +                       res_valid |= !(res->flags & IORESOURCE_PREFETCH);
> +                       cra_writel(pcie, res->start,
> +                               A2P_ADDR_MAP_LO0 + offset);
> +                       cra_writel(pcie, 0,
> +                               A2P_ADDR_MAP_HI0 + offset);
> +                       offset += ATT_ENTRY_SIZE;
> +                       break;
> +               default:
> +                       continue;
> +               }
> +
> +               err = devm_request_resource(dev, parent, res);
> +               if (err)
> +                       goto out_release_res;
> +       }
> +
> +       if (!res_valid) {
> +               dev_err(dev, "non-prefetchable memory resource required\n");
> +               err = -EINVAL;
> +               goto out_release_res;
> +       }
> +
> +       return 0;
> +
> +out_release_res:
> +       altera_pcie_release_of_pci_ranges(pcie);
> +       return err;
> +}
> +
> +static void altera_pcie_free_irq_domain(struct altera_pcie *pcie)
> +{
> +       int i;
> +       u32 irq;
> +
> +       for (i = 0; i < INTX_NUM; i++) {
> +               irq = irq_find_mapping(pcie->irq_domain, i);
> +               if (irq > 0)
> +                       irq_dispose_mapping(irq);
> +       }
> +
> +       irq_domain_remove(pcie->irq_domain);
> +}
> +
> +static int altera_pcie_init_irq_domain(struct altera_pcie *pcie)
> +{
> +       struct device *dev = &pcie->pdev->dev;
> +       struct device_node *node = dev->of_node;
> +
> +       /* Setup INTx */
> +       pcie->irq_domain = irq_domain_add_linear(node, INTX_NUM,
> +                                       &intx_domain_ops, pcie);
> +       if (!pcie->irq_domain) {
> +               dev_err(dev, "Failed to get a INTx IRQ domain\n");
> +               return PTR_ERR(pcie->irq_domain);
> +       }
> +
> +       return 0;
> +}
> +
> +static int altera_pcie_parse_dt(struct altera_pcie *pcie)
> +{
> +       struct resource *cra;
> +       int ret;
> +       struct platform_device *pdev = pcie->pdev;
> +
> +       cra = platform_get_resource_byname(pdev, IORESOURCE_MEM, "Cra");
> +       pcie->cra_base = devm_ioremap_resource(&pdev->dev, cra);
> +       if (IS_ERR(pcie->cra_base)) {
> +               dev_err(&pdev->dev, "get Cra resource failed\n");
> +               return PTR_ERR(pcie->cra_base);
> +       }
> +
> +       /* setup IRQ */
> +       pcie->hwirq = platform_get_irq(pdev, 0);
> +       if (pcie->hwirq <= 0) {
> +               dev_err(&pdev->dev, "failed to get IRQ: %d\n", pcie->hwirq);
> +               return -EINVAL;
> +       }
> +       ret = devm_request_irq(&pdev->dev, pcie->hwirq, altera_pcie_isr,
> +                       IRQF_SHARED, pdev->name, pcie);
> +
> +       if (ret) {
> +               dev_err(&pdev->dev, "failed to request irq %d\n", pcie->hwirq);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int altera_pcie_probe(struct platform_device *pdev)
> +{
> +       struct altera_pcie *pcie;
> +       int ret;
> +
> +       pcie = devm_kzalloc(&pdev->dev, sizeof(*pcie), GFP_KERNEL);
> +       if (!pcie)
> +               return -ENOMEM;
> +
> +       pcie->pdev = pdev;
> +
> +       ret = altera_pcie_parse_dt(pcie);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Parsing DT failed\n");
> +               return ret;
> +       }
> +
> +       INIT_LIST_HEAD(&pcie->resources);
> +
> +       ret = altera_pcie_parse_request_of_pci_ranges(pcie);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Failed add resources\n");
> +               return ret;
> +       }
> +
> +       ret = altera_pcie_init_irq_domain(pcie);

I don't think you need an irq domain here.

> +       if (ret) {
> +               dev_err(&pdev->dev, "Failed creating IRQ Domain\n");
> +               return ret;
> +       }
> +
> +       pcie->root_bus_nr = -1;
> +
> +       /* clear all interrupts */
> +       cra_writel(pcie, P2A_INT_STS_ALL, P2A_INT_STATUS);
> +       /* enable all interrupts */
> +       cra_writel(pcie, P2A_INT_ENA_ALL, P2A_INT_ENABLE);
> +
> +       altera_pcie_hw.private_data = (void **)&pcie;
> +
> +       pci_common_init_dev(&pdev->dev, &altera_pcie_hw);

You should not call this, but call pci_scan_root_bus directly. See
pci-host-generic.c or pci-versatile.c for examples.

Rob
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