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Message-ID: <55C4C1E2.7080205@arm.com>
Date: Fri, 07 Aug 2015 15:34:10 +0100
From: Marc Zyngier <marc.zyngier@....com>
To: Ley Foon Tan <lftan@...era.com>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Russell King <linux@....linux.org.uk>
CC: Arnd Bergmann <arnd@...db.de>,
Dinh Nguyen <dinguyen@...nsource.altera.com>,
"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"lftan.linux@...il.com" <lftan.linux@...il.com>,
Rob Herring <robh+dt@...nel.org>
Subject: Re: [PATCH v3 2/5] pci:host: Add Altera PCIe host controller driver
On 07/08/15 08:42, Ley Foon Tan wrote:
> This patch adds the Altera PCIe host controller driver.
>
> Signed-off-by: Ley Foon Tan <lftan@...era.com>
> ---
> drivers/pci/host/Kconfig | 7 +
> drivers/pci/host/Makefile | 1 +
> drivers/pci/host/pcie-altera.c | 532 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 540 insertions(+)
> create mode 100644 drivers/pci/host/pcie-altera.c
>
> diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
> index 675c2d1..4b4754a 100644
> --- a/drivers/pci/host/Kconfig
> +++ b/drivers/pci/host/Kconfig
> @@ -145,4 +145,11 @@ 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
> + tristate "Altera PCIe controller"
> + depends on ARCH_SOCFPGA
> + 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..37bed81
> --- /dev/null
> +++ b/drivers/pci/host/pcie-altera.c
> @@ -0,0 +1,532 @@
> +/*
> + * 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/irqchip/chained_irq.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 irq;
> + 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 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_relaxed(value, pcie->cra_base + reg);
> +}
> +
> +static inline u32 cra_readl(struct altera_pcie *pcie, u32 reg)
> +{
> + return readl_relaxed(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--) {
I'd prefer to see the more common idiom:
for (loop = 0; loop < TLP_LOOP; 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;
> + }
Don't you need some form of relaxation here? A delay of some sort?
Repeatedly polling the HW is usually not helping it to recover...
> + }
> +
> + 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 = 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 = 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_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 void altera_pcie_isr(unsigned int irq, struct irq_desc *desc)
> +{
> + struct irq_chip *chip = irq_desc_get_chip(desc);
> + struct altera_pcie *pcie;
> + unsigned long status;
> + u32 bit;
> + u32 virq;
> +
> + chained_irq_enter(chip, desc);
> + pcie = irq_desc_get_handler_data(desc);
> +
> + do {
> + status = cra_readl(pcie, P2A_INT_STATUS) & P2A_INT_STS_ALL;
> + if (!status)
> + break;
> +
> + do {
> + bit = find_first_bit(&status, INTX_NUM);
> + /* clear interrupts */
> + cra_writel(pcie, 1 << bit, P2A_INT_STATUS);
> +
> + virq = irq_find_mapping(pcie->irq_domain, bit + 1);
> + if (virq)
> + generic_handle_irq(virq);
> + else
> + dev_info(&pcie->pdev->dev, "unexpected IRQ\n");
> +
> + /* Clear the bit from status and repeat without reading
> + * again status register. */
> + __clear_bit(bit, &status);
> + } while (status);
> + } while (1);
> +
> + chained_irq_exit(chip, desc);
> +}
> +
> +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;
> +
> + 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);
> + 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);
Err, no. irq_domain_add returns NULL on error, so PTR_ERR(NULL) is still
going to be zero.
> + }
> +
> + return 0;
> +}
> +
> +static int altera_pcie_parse_dt(struct altera_pcie *pcie)
> +{
> + struct resource *cra;
> + struct platform_device *pdev = pcie->pdev;
> +
> + cra = platform_get_resource_byname(pdev, IORESOURCE_MEM, "Cra");
Probably worth checking that this hasn't failed.
> + 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->irq = platform_get_irq(pdev, 0);
> + if (pcie->irq <= 0) {
> + dev_err(&pdev->dev, "failed to get IRQ: %d\n", pcie->irq);
> + return -EINVAL;
> + }
> +
> + irq_set_chained_handler_and_data(pcie->irq, altera_pcie_isr, pcie);
> +
> + return 0;
> +}
> +
> +static int altera_pcie_probe(struct platform_device *pdev)
> +{
> + struct altera_pcie *pcie;
> + struct pci_bus *bus;
> + 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);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed creating IRQ Domain\n");
> + return ret;
> + }
> +
> + pcie->root_bus_nr = 0;
> +
> + /* 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);
> +
> + bus = pci_scan_root_bus(&pdev->dev, pcie->root_bus_nr, &altera_pcie_ops,
> + pcie, &pcie->resources);
> + if (!bus)
> + return -ENOMEM;
> +
> + pci_fixup_irqs(pci_common_swizzle, of_irq_parse_and_map_pci);
> + pci_assign_unassigned_bus_resources(bus);
> + pci_bus_add_devices(bus);
> +
> + platform_set_drvdata(pdev, pcie);
> + return ret;
> +}
> +
> +static int __exit altera_pcie_remove(struct platform_device *pdev)
> +{
> + struct altera_pcie *pcie = platform_get_drvdata(pdev);
> +
> + altera_pcie_free_irq_domain(pcie);
> + platform_set_drvdata(pdev, NULL);
> + return 0;
> +}
> +
> +static const struct of_device_id altera_pcie_of_match[] = {
> + { .compatible = "altr,pcie-root-port-1.0", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, altera_pcie_of_match);
> +
> +static struct platform_driver altera_pcie_driver = {
> + .probe = altera_pcie_probe,
> + .remove = altera_pcie_remove,
> + .driver = {
> + .name = "altera-pcie",
> + .of_match_table = altera_pcie_of_match,
> + },
> +};
> +
> +module_platform_driver(altera_pcie_driver);
> +
> +MODULE_AUTHOR("Ley Foon Tan <lftan@...era.com>");
> +MODULE_DESCRIPTION("Altera PCIe host controller driver");
> +MODULE_LICENSE("GPL v2");
> --
> 1.8.2.1
>
This is starting to look better. You should get someone to review the DT
parts though.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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