Hi Joao,
This is getting pretty close. I have a few comments below. This is a
new driver, with no chance of breaking anything else, so I think we
can still get it in for v4.5.
Bjorn
On Thu, Jan 14, 2016 at 11:04:33AM +0000, Joao Pinto wrote:
> This patch adds a new driver that will be the reference platform driver
> for all PCI RC IP Protoyping Kits based on ARC SDP.
> This patch is composed by:
>
> -Changes to pcie-designware driver add a function that enables the
> feature of starting the LTSSM (Link Train Status State) used by the
> new driver
> -MAINTAINERS file was updated to include the new driver
> -Documentation/devicetree/bindings/pci was updated to include the new
> driver documentation
> -New driver called pcie-snpsdev
>
> Signed-off-by: Joao Pinto <jpinto@xxxxxxxxxxxx>
> ---
> Change v5 -> v6:
> - Nothing changed (just to keep up with patch set version).
> Change v4 -> v5:
> - Nothing changed (just to keep up with patch set version).
> Changes v3 -> v4 (Bjorn Helgaas):
> - ARCH dependencies were added to the drivers/pci/host/kconfig for the
> PCIE_SNPSDEV.
> Changes v2 -> v3 (Bjorn Helgaas):
> - link init stuff was moved to a snpsdev_pcie_establish_link() function in
> pcie-snpsdev
> - pcie-snpsdev driver declaration was changed to be more
> standard (Bjorn Helgaas)
> - pcie-designware' dw_pcie_link_retrain() now use standard registers from
> pci-regs.h (Bjorn Helgaas)
> - pcie-snpsdev.txt was complemented with more info (Mark Rutland)
> Changes v1 -> v2 (Bjorn Helgaas):
> - Fixups snpsdev_pcie_fixup_bridge() and snpsdev_pcie_fixup_res() were removed
> from the driver (these functions were for specific tests only and not usefull
> in mainline)
> - Driver' comments were reviewed (fix Typos and excessive comments removal)
> - Removed unnecessary definitions in the driver source (PCIE_PHY_CTRL and
> PCIE_PHY_STAT)
>
> .../devicetree/bindings/pci/pcie-snpsdev.txt | 33 +++
> MAINTAINERS | 7 +
> drivers/pci/host/Kconfig | 8 +
> drivers/pci/host/Makefile | 1 +
> drivers/pci/host/pcie-designware.c | 9 +
> drivers/pci/host/pcie-designware.h | 1 +
> drivers/pci/host/pcie-snpsdev.c | 286 +++++++++++++++++++++
> 7 files changed, 345 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/pci/pcie-snpsdev.txt
> create mode 100644 drivers/pci/host/pcie-snpsdev.c
>
> diff --git a/Documentation/devicetree/bindings/pci/pcie-snpsdev.txt b/Documentation/devicetree/bindings/pci/pcie-snpsdev.txt
> new file mode 100644
> index 0000000..cae548b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pci/pcie-snpsdev.txt
> @@ -0,0 +1,33 @@
> +Synopsys PCI RC IP Prototyping Kit
> +----------------------------------
> +
> +This is the reference platform driver to be used in the Synopsys PCI Root
> +Complex IP Prototyping Kit.
> +
> +Required properties:
> +- compatible: set to "snps,pcie-snpsdev";
> +- reg: base address and length of the pcie controller registers.
> +- #address-cells: set to <3>
> +- #size-cells: set to <2>
> +- device_type: set to "pci"
> +- ranges: ranges for the PCI memory and I/O regions.
> +- interrupts: one interrupt source for MSI interrupts, followed by interrupt
> + source for hardware related interrupts.
> +- #interrupt-cells: set to <1>
> +- num-lanes: set to <1>;
> +
> +Example configuration:
> +
> + pcie: pcie@0xdffff000 {
> + compatible = "snps,pcie-snpsdev";
> + reg = <0xdffff000 0x1000>;
> + #address-cells = <3>;
> + #size-cells = <2>;
> + device_type = "pci";
> + ranges = <0x00000800 0 0xd0000000 0xd0000000 0 0x00002000>,
> + <0x81000000 0 0x00000000 0xde000000 0 0x00010000>,
> + <0x82000000 0 0xd0400000 0xd0400000 0 0x0d000000>;
> + interrupts = <25>, <24>;
> + #interrupt-cells = <1>;
> + num-lanes = <1>;
> + };
Can we get an ack from the DT guys for this?
Is "snpsdev" an already-established abbreviation? The "dev" part
seems obvious and maybe could go without saying. This would look
nicer if we could just use "synopsis" everywhere you have "snpsdev" --
DT compatible string, filename, function names, etc.
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e9caa4b..d2e4506 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -8230,6 +8230,13 @@ S: Maintained
> F: Documentation/devicetree/bindings/pci/hisilicon-pcie.txt
> F: drivers/pci/host/pcie-hisi.c
>
> +PCI DRIVER FOR SYNOPSYS PROTOTYPING DEVICE
> +M: Joao Pinto <jpinto@xxxxxxxxxxxx>
> +L: linux-pci@xxxxxxxxxxxxxxx
> +S: Maintained
> +F: Documentation/devicetree/bindings/pci/pcie-snpsdev.txt
> +F: drivers/pci/host/pcie-snpsdev.c
> +
> PCMCIA SUBSYSTEM
> P: Linux PCMCIA Team
> L: linux-pcmcia@xxxxxxxxxxxxxxxxxxx
> diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
> index f131ba9..589bc15 100644
> --- a/drivers/pci/host/Kconfig
> +++ b/drivers/pci/host/Kconfig
> @@ -172,4 +172,12 @@ config PCI_HISI
> help
> Say Y here if you want PCIe controller support on HiSilicon HIP05 SoC
>
> +config PCIE_SNPSDEV
> + bool "Platform Driver for Synopsys Device"
> + depends on ARC && OF
> + select PCIEPORTBUS
> + select PCIE_DW
> + help
> + Say Y here if you want to enable PCIe controller support on the
> + Synopsys IP Prototyping Kits.
> endmenu
> diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
> index 9d4d3c6..e422f65 100644
> --- a/drivers/pci/host/Makefile
> +++ b/drivers/pci/host/Makefile
> @@ -20,3 +20,4 @@ obj-$(CONFIG_PCIE_IPROC_BCMA) += pcie-iproc-bcma.o
> obj-$(CONFIG_PCIE_ALTERA) += pcie-altera.o
> obj-$(CONFIG_PCIE_ALTERA_MSI) += pcie-altera-msi.o
> obj-$(CONFIG_PCI_HISI) += pcie-hisi.o
> +obj-$(CONFIG_PCIE_SNPSDEV) += pcie-snpsdev.o
> diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
> index 540f077..f73a3cf 100644
> --- a/drivers/pci/host/pcie-designware.c
> +++ b/drivers/pci/host/pcie-designware.c
> @@ -706,6 +706,15 @@ static struct pci_ops dw_pcie_ops = {
> .write = dw_pcie_wr_conf,
> };
>
> +void dw_pcie_link_retrain(struct pcie_port *pp)
> +{
> + u32 val = 0;
> +
> + dw_pcie_readl_rc(pp, PCI_EXP_LNKCTL+0x70, &val);
> + val = val | PCI_EXP_LNKCTL_RL;
> + dw_pcie_writel_rc(pp, val, PCI_EXP_LNKCTL+0x70);
> +}
It seems odd that you need to add this. Please split it into a
separate patch and we can get the DW guys to ack it.
> +
> void dw_pcie_setup_rc(struct pcie_port *pp)
> {
> u32 val;
> diff --git a/drivers/pci/host/pcie-designware.h b/drivers/pci/host/pcie-designware.h
> index 2356d29..249b631 100644
> --- a/drivers/pci/host/pcie-designware.h
> +++ b/drivers/pci/host/pcie-designware.h
> @@ -79,5 +79,6 @@ void dw_pcie_msi_init(struct pcie_port *pp);
> int dw_pcie_link_up(struct pcie_port *pp);
> void dw_pcie_setup_rc(struct pcie_port *pp);
> int dw_pcie_host_init(struct pcie_port *pp);
> +void dw_pcie_link_retrain(struct pcie_port *pp);
>
> #endif /* _PCIE_DESIGNWARE_H */
> diff --git a/drivers/pci/host/pcie-snpsdev.c b/drivers/pci/host/pcie-snpsdev.c
> new file mode 100644
> index 0000000..4ca7ec5
> --- /dev/null
> +++ b/drivers/pci/host/pcie-snpsdev.c
> @@ -0,0 +1,286 @@
> +/*
> + * PCIe RC driver for Synopsys Designware Core
> + *
> + * Copyright (C) 2015-2016 Synopsys, Inc. (www.synopsys.com)
> + *
> + * Authors: Manjunath Bettegowda <manjumb@xxxxxxxxxxxx>,
> + * Jie Deng <jiedeng@xxxxxxxxxxxx>
> + * Joao Pinto <jpinto@xxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/gpio.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_gpio.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/resource.h>
> +#include <linux/signal.h>
> +#include <linux/types.h>
> +
> +#include "pcie-designware.h"
> +
> +#define to_snpsdev_pcie(x) container_of(x, struct snpsdev_pcie, pp)
> +
> +struct snpsdev_pcie {
> + void __iomem *mem_base; /* Memory Base to access Core's [RC]
> + * Config Space Layout
> + */
> + struct pcie_port pp; /* RC Root Port specific structure -
> + * DWC_PCIE_RC stuff
> + */
> +};
> +
> +#define PCI_EQUAL_CONTROL_PHY 0x00000707
> +
> +/* PCIe Port Logic registers (memory-mapped) */
> +#define PLR_OFFSET 0x700
> +#define PCIE_PHY_DEBUG_R0 (PLR_OFFSET + 0x28) /* 0x728 */
> +#define PCIE_PHY_DEBUG_R1 (PLR_OFFSET + 0x2c) /* 0x72c */
> +
> +/* This handler was created for future work */
> +static irqreturn_t snpsdev_pcie_irq_handler(int irq, void *arg)
> +{
> + return IRQ_NONE;
> +}
> +
> +static irqreturn_t snpsdev_pcie_msi_irq_handler(int irq, void *arg)
> +{
> + struct pcie_port *pp = arg;
> +
> + dw_handle_msi_irq(pp);
> +
> + return IRQ_HANDLED;
I think this should be
return dw_handle_msi_irq(pp);
as it is in other DW-based drivers (or there should be a comment about
why this needs to be different).
> +}
> +
> +static void snpsdev_pcie_init_phy(struct pcie_port *pp)
> +{
> + /* write Lane 0 Equalization Control fields register */
> + writel(PCI_EQUAL_CONTROL_PHY, pp->dbi_base + 0x154);
> +}
> +
> +static int snpsdev_pcie_deassert_core_reset(struct pcie_port *pp)
> +{
> + return 0;
> +}
> +
> +static void snpsdev_pcie_establish_link(struct pcie_port *pp)
> +{
> + int count = 0;
> +
> + /* Initialize Phy (Reset/poweron/control-inputs ) */
> + snpsdev_pcie_init_phy(pp);
> +
> + /* de-assert core reset */
Superfluous comment, since the function name repeats exactly the same
thing. The one above is probably superfluous, too.
> + snpsdev_pcie_deassert_core_reset(pp);
> +
> + /* We expect the PCIe Link to be up by this time */
Is the comment really true? It seems strange to retrain the link
below if you expect it to already be up before you even call
dw_pcie_setup_rc().
> + dw_pcie_setup_rc(pp);
I count 7 existing callers of dw_pcie_setup_rc(). 4 are from
*_pcie_host_init(), and 3 are from *_pcie_establish_link(). Let's
follow the trend by doing the things above in
snpsdev_pcie_host_init(). Unless there's a *reason* to be different,
I want all these DW-based drivers to look as much alike as possible.
> +
> + /* Start LTSSM here */
> + dw_pcie_link_retrain(pp);
What's different about this system that means you require this
link_retrain() interface, when all the other drivers don't?
> +
> + while (!dw_pcie_link_up(pp)) {
> + usleep_range(1000, 1100);
> + count++;
> + if (count == 20) {
> + dev_err(pp->dev, "phy link never came up\n");
> + dev_dbg(pp->dev,
> + "PL_DEBUG0: 0x%08x, DEBUG_R1: 0x%08x\n",
> + readl(pp->dbi_base + PCIE_PHY_DEBUG_R0),
> + readl(pp->dbi_base + PCIE_PHY_DEBUG_R1));
> + break;
> + }
> + }
Can you look at the other DW-based drivers and copy their "wait for
link up" code? This is basically similar, but again, doing it
"basically similar but slightly different" just makes work and errors.
> +}
> +
> +/*
> + * snpsdev_pcie_host_init()
> + * Platform specific host/RC initialization
> + * a. Assert the core reset
> + * b. Assert and deassert phy reset and initialize the phy
> + * c. De-Assert the core reset
> + * d. Initializet the Root Port (BARs/Memory Or IO/ Interrupt/ Commnad Reg)
> + * e. Initiate Link startup procedure
> + *
> + */
> +static void snpsdev_pcie_host_init(struct pcie_port *pp)
> +{
> + /* Establish link */
Superfluous comment.
> + snpsdev_pcie_establish_link(pp);
> +
> + if (IS_ENABLED(CONFIG_PCI_MSI))
> + dw_pcie_msi_init(pp);
> +}
> +
> +static int snpsdev_pcie_link_up(struct pcie_port *pp)
> +{
> + u32 status;
> +
> + /* Bit number 36: reports LTSSM PHY Link UP; Available in bit 3 of
> + * PCIE_PHY_DEBUG_R1
> + */
> + status = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1) & (0x1 << 4);
> + if (status != 0)
> + return 1;
This would be easier to read as something like:
#define PCIE_PHY_DEBUG_R1_LINK_UP 0x00000010
val = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1);
return val & PCIE_PHY_DEBUG_R1_LINK_UP;
> +
> + /* TODO:Now Link is in L0;Initiate GEN2/GEN3 migration if RC Supports*/
> + return 0;
> +}
> +
> +/**
> + * This is RC operation structure
> + * snpsdev_pcie_link_up: the function which initiates the phy link up procedure
> + * snpsdev_pcie_host_init: the function which does the host/RC Root port
> + * initialization.
> + */
> +static struct pcie_host_ops snpsdev_pcie_host_ops = {
> + .link_up = snpsdev_pcie_link_up,
> + .host_init = snpsdev_pcie_host_init,
> +};
> +
> +/**
> + * snpsdev_add_pcie_port
> + * This function
> + * a. installs the interrupt handler
> + * b. registers host operations in the pcie_port structure
> + */
> +static int snpsdev_add_pcie_port(struct pcie_port *pp,
> + struct platform_device *pdev)
> +{
> + int ret;
> +
> + pp->irq = platform_get_irq(pdev, 1);
> +
> + if (pp->irq < 0) {
> + if (pp->irq != -EPROBE_DEFER)
> + dev_err(&pdev->dev, "cannot get irq\n");
Hmmm... I don't really understand this EPROBE_DEFER stuff. Most
callers of platform_get_irq() don't check for it explicitly (and
*none* of the DW-based drivers does), so I hope it's not something
drivers are supposed to do something special with. In this case, the
only difference is makes is whether you print a message, so my advice
is to just print the message unconditionally if platform_get_irq()
fails for any reason.
> + return pp->irq;
> + }
> +
> + ret = devm_request_irq(&pdev->dev, pp->irq, snpsdev_pcie_irq_handler,
> + IRQF_SHARED, "snpsdev-pcie", pp);
> +
> + if (ret) {
> + dev_err(&pdev->dev, "failed to request irq\n");
> + return ret;
> + }
> +
> + if (IS_ENABLED(CONFIG_PCI_MSI)) {
> + pp->msi_irq = platform_get_irq(pdev, 0);
> +
> + if (pp->msi_irq < 0) {
> + if (pp->msi_irq != -EPROBE_DEFER)
> + dev_err(&pdev->dev, "cannot get msi irq\n");
Same here.
> + return pp->msi_irq;
> + }
> +
> + ret = devm_request_irq(&pdev->dev, pp->msi_irq,
> + snpsdev_pcie_msi_irq_handler,
> + IRQF_SHARED, "snpsdev-pcie-msi", pp);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to request msi irq\n");
> + return ret;
> + }
> + }
> +
> + pp->root_bus_nr = -1;
> + pp->ops = &snpsdev_pcie_host_ops;
> +
> + /* Below function:
> + * Checks for range property from DT
> + * Gets the IO and MEMORY and CONFIG-Space ranges from DT
> + * Does IOREMAPS on the physical addresses
> + * Gets the num-lanes from DT
> + * Gets MSI capability from DT
> + * Calls the platform specific host initialization
> + * Program the correct class, BAR0, Link width, in Config space
> + * Then it calls pci common init routine
> + * Then it calls function to assign "unassigned resources"
> + */
> + ret = dw_pcie_host_init(pp);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to initialize host\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * snpsdev_pcie_rc_probe()
> + * This function gets called as part of pcie registration. if the id matches
> + * the platform driver framework will call this function.
> + *
> + * @pdev: Pointer to the platform_device structure
> + *
> + * Returns zero on success; Negative errorno on failure
> + */
> +static int snpsdev_pcie_rc_probe(struct platform_device *pdev)
snpsdev_pcie_probe() (so it follows the pattern of other drivers).
> +{
> + struct snpsdev_pcie *snpsdev_pcie;
> + struct pcie_port *pp;
> + struct resource *dwc_pcie_rc_res; /* Resource from DT */
"res" would be a good enough name and would avoid line wrapping below.
> + int ret;
> +
> + snpsdev_pcie = devm_kzalloc(&pdev->dev, sizeof(*snpsdev_pcie),
> + GFP_KERNEL);
> + if (!snpsdev_pcie)
> + return -ENOMEM;
> +
> + pp = &snpsdev_pcie->pp;
> + pp->dev = &pdev->dev;
> +
> + dwc_pcie_rc_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +
> + if (!dwc_pcie_rc_res)
> + return -ENODEV;
> +
> + snpsdev_pcie->mem_base = devm_ioremap_resource(&pdev->dev,
> + dwc_pcie_rc_res);
> + if (IS_ERR(snpsdev_pcie->mem_base)) {
> + ret = PTR_ERR(snpsdev_pcie->mem_base);
> + return ret;
return PTR_ERR(snpsdev_pcie->mem_base);
> + }
> + pp->dbi_base = snpsdev_pcie->mem_base;
> +
> + ret = snpsdev_add_pcie_port(pp, pdev);
> + if (ret < 0)
> + return ret;
> +
> + platform_set_drvdata(pdev, snpsdev_pcie);
> +
> + return 0;
> +}
> +
> +static int snpsdev_pcie_rc_remove(struct platform_device *pdev)
> +{
> + return 0;
> +}
This isn't referenced anywhere, so I think you could remove it.
> +static const struct of_device_id snpsdev_pcie_rc_of_match[] = {
> + { .compatible = "snps,pcie-snpsdev", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, snpsdev_pcie_rc_of_match);
> +
> +static struct platform_driver snpsdev_pcie_rc_driver = {
> + .driver = {
> + .name = "pcie-snpsdev",
> + .of_match_table = snpsdev_pcie_rc_of_match,
> + },
> + .probe = snpsdev_pcie_rc_probe,
> +};
> +
> +module_platform_driver(snpsdev_pcie_rc_driver);
> +
> +MODULE_AUTHOR("Manjunath Bettegowda <manjumb@xxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Platform Driver for Synopsys Device");
Should probably mention the PCI connection, e.g., "Synopsys PCIe host
controller driver".
> +MODULE_LICENSE("GPL v2");
> --
> 1.8.1.5
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