Re: [PATCH v2 2/6] PCI: apple: Add initial hardware bring-up

From: Mark Kettenis
Date: Sun Aug 22 2021 - 14:42:52 EST

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> From: Alyssa Rosenzweig <alyssa@xxxxxxxxxxxxx>
> Date: Sun, 15 Aug 2021 23:16:17 -0400
>
> Add a minimal driver to bring up the PCIe bus on Apple system-on-chips,
> particularly the Apple M1. This driver exposes the internal bus used for
> the USB type-A ports, Ethernet, Wi-Fi, and Bluetooth. Bringing up the
> radios requires additional drivers beyond what's necessary for PCIe
> itself.
>
> In this patch, a minimal driver is added that brings up the PCIe bus on
> probe. This logic is derived from Corellium's driver via Mark Kettenis's
> U-Boot patches.
>
> Co-developed-by: Stan Skowronek <stan@xxxxxxxxxxxxx>
> Signed-off-by: Stan Skowronek <stan@xxxxxxxxxxxxx>
> Signed-off-by: Alyssa Rosenzweig <alyssa@xxxxxxxxxxxxx>
> ---
> MAINTAINERS | 6 +
> drivers/pci/controller/Kconfig | 12 ++
> drivers/pci/controller/Makefile | 1 +
> drivers/pci/controller/pcie-apple.c | 251 ++++++++++++++++++++++++++++
> 4 files changed, 270 insertions(+)
> create mode 100644 drivers/pci/controller/pcie-apple.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a5687cf6f925..47cb3d320c56 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1269,6 +1269,12 @@ S: Maintained
> F: Documentation/devicetree/bindings/iommu/apple,dart.yaml
> F: drivers/iommu/apple-dart.c
>
> +APPLE PCIE CONTROLLER DRIVER
> +M: Alyssa Rosenzweig <alyssa@xxxxxxxxxxxxx>
> +L: linux-pci@xxxxxxxxxxxxxxx
> +S: Maintained
> +F: drivers/pci/controller/pcie-apple.c
> +
> APPLE SMC DRIVER
> M: Henrik Rydberg <rydberg@xxxxxxxxxxx>
> L: linux-hwmon@xxxxxxxxxxxxxxx
> diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
> index 326f7d13024f..814833a8120d 100644
> --- a/drivers/pci/controller/Kconfig
> +++ b/drivers/pci/controller/Kconfig
> @@ -312,6 +312,18 @@ config PCIE_HISI_ERR
> Say Y here if you want error handling support
> for the PCIe controller's errors on HiSilicon HIP SoCs
>
> +config PCIE_APPLE
> + tristate "Apple PCIe controller"
> + depends on ARCH_APPLE || COMPILE_TEST
> + depends on OF
> + depends on PCI_MSI_IRQ_DOMAIN
> + help
> + Say Y here if you want to enable PCIe controller support on Apple
> + system-on-chips, like the Apple M1. This is required for the USB
> + type-A ports, Ethernet, Wi-Fi, and Bluetooth.
> +
> + If unsure, say Y if you have an Apple Silicon system.
> +
> source "drivers/pci/controller/dwc/Kconfig"
> source "drivers/pci/controller/mobiveil/Kconfig"
> source "drivers/pci/controller/cadence/Kconfig"
> diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile
> index aaf30b3dcc14..f9d40bad932c 100644
> --- a/drivers/pci/controller/Makefile
> +++ b/drivers/pci/controller/Makefile
> @@ -37,6 +37,7 @@ obj-$(CONFIG_VMD) += vmd.o
> obj-$(CONFIG_PCIE_BRCMSTB) += pcie-brcmstb.o
> obj-$(CONFIG_PCI_LOONGSON) += pci-loongson.o
> obj-$(CONFIG_PCIE_HISI_ERR) += pcie-hisi-error.o
> +obj-$(CONFIG_PCIE_APPLE) += pcie-apple.o
> # pcie-hisi.o quirks are needed even without CONFIG_PCIE_DW
> obj-y += dwc/
> obj-y += mobiveil/
> diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
> new file mode 100644
> index 000000000000..a1efcc3373ea
> --- /dev/null
> +++ b/drivers/pci/controller/pcie-apple.c
> @@ -0,0 +1,251 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * PCIe host bridge driver for Apple system-on-chips.
> + *
> + * The HW is ECAM compliant, so once the controller is initialized, the driver
> + * mostly only needs MSI handling. Initialization requires enabling power and
> + * clocks, along with a number of register pokes.
> + *
> + * Copyright (C) 2021 Alyssa Rosenzweig <alyssa@xxxxxxxxxxxxx>
> + * Copyright (C) 2021 Google LLC
> + * Copyright (C) 2021 Corellium LLC
> + * Copyright (C) 2021 Mark Kettenis <kettenis@xxxxxxxxxxx>
> + *
> + * Author: Alyssa Rosenzweig <alyssa@xxxxxxxxxxxxx>
> + * Author: Marc Zyngier <maz@xxxxxxxxxx>
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/irqdomain.h>
> +#include <linux/module.h>
> +#include <linux/msi.h>
> +#include <linux/of_irq.h>
> +#include <linux/pci-ecam.h>
> +#include <linux/iopoll.h>
> +#include <linux/gpio/consumer.h>
> +
> +#define CORE_RC_PHYIF_CTL 0x00024
> +#define CORE_RC_PHYIF_CTL_RUN BIT(0)
> +#define CORE_RC_PHYIF_STAT 0x00028
> +#define CORE_RC_PHYIF_STAT_REFCLK BIT(4)
> +#define CORE_RC_CTL 0x00050
> +#define CORE_RC_CTL_RUN BIT(0)
> +#define CORE_RC_STAT 0x00058
> +#define CORE_RC_STAT_READY BIT(0)
> +#define CORE_FABRIC_STAT 0x04000
> +#define CORE_FABRIC_STAT_MASK 0x001F001F
> +#define CORE_LANE_CFG(port) (0x84000 + 0x4000 * (port))
> +#define CORE_LANE_CFG_REFCLK0REQ BIT(0)
> +#define CORE_LANE_CFG_REFCLK1 BIT(1)
> +#define CORE_LANE_CFG_REFCLK0ACK BIT(2)
> +#define CORE_LANE_CFG_REFCLKEN (BIT(9) | BIT(10))
> +#define CORE_LANE_CTL(port) (0x84004 + 0x4000 * (port))
> +#define CORE_LANE_CTL_CFGACC BIT(15)
> +
> +#define PORT_LTSSMCTL 0x00080
> +#define PORT_LTSSMCTL_START BIT(0)
> +#define PORT_INTSTAT 0x00100
> +#define PORT_INT_TUNNEL_ERR BIT(31)
> +#define PORT_INT_CPL_TIMEOUT BIT(23)
> +#define PORT_INT_RID2SID_MAPERR BIT(22)
> +#define PORT_INT_CPL_ABORT BIT(21)
> +#define PORT_INT_MSI_BAD_DATA BIT(19)
> +#define PORT_INT_MSI_ERR BIT(18)
> +#define PORT_INT_REQADDR_GT32 BIT(17)
> +#define PORT_INT_AF_TIMEOUT BIT(15)
> +#define PORT_INT_LINK_DOWN BIT(14)
> +#define PORT_INT_LINK_UP BIT(12)
> +#define PORT_INT_LINK_BWMGMT BIT(11)
> +#define PORT_INT_AER_MASK (15 << 4)
> +#define PORT_INT_PORT_ERR BIT(4)
> +#define PORT_INT_INTx(i) BIT(i)
> +#define PORT_INT_INTxALL 15
> +#define PORT_INTMSK 0x00104
> +#define PORT_INTMSKSET 0x00108
> +#define PORT_INTMSKCLR 0x0010c
> +#define PORT_MSICFG 0x00124
> +#define PORT_MSICFG_EN BIT(0)
> +#define PORT_MSICFG_L2MSINUM_SHIFT 4
> +#define PORT_MSIBASE 0x00128
> +#define PORT_MSIBASE_1_SHIFT 16
> +#define PORT_MSIADDR 0x00168
> +#define PORT_LINKSTS 0x00208
> +#define PORT_LINKSTS_UP BIT(0)
> +#define PORT_LINKSTS_BUSY BIT(2)
> +#define PORT_LINKCMDSTS 0x00210
> +#define PORT_OUTS_NPREQS 0x00284
> +#define PORT_OUTS_NPREQS_REQ BIT(24)
> +#define PORT_OUTS_NPREQS_CPL BIT(16)
> +#define PORT_RXWR_FIFO 0x00288
> +#define PORT_RXWR_FIFO_HDR GENMASK(15, 10)
> +#define PORT_RXWR_FIFO_DATA GENMASK(9, 0)
> +#define PORT_RXRD_FIFO 0x0028C
> +#define PORT_RXRD_FIFO_REQ GENMASK(6, 0)
> +#define PORT_OUTS_CPLS 0x00290
> +#define PORT_OUTS_CPLS_SHRD GENMASK(14, 8)
> +#define PORT_OUTS_CPLS_WAIT GENMASK(6, 0)
> +#define PORT_APPCLK 0x00800
> +#define PORT_APPCLK_EN BIT(0)
> +#define PORT_APPCLK_CGDIS BIT(8)
> +#define PORT_STATUS 0x00804
> +#define PORT_STATUS_READY BIT(0)
> +#define PORT_REFCLK 0x00810
> +#define PORT_REFCLK_EN BIT(0)
> +#define PORT_REFCLK_CGDIS BIT(8)
> +#define PORT_PERST 0x00814
> +#define PORT_PERST_OFF BIT(0)
> +#define PORT_RID2SID(i16) (0x00828 + 4 * (i16))
> +#define PORT_RID2SID_VALID BIT(31)
> +#define PORT_RID2SID_SID_SHIFT 16
> +#define PORT_RID2SID_BUS_SHIFT 8
> +#define PORT_RID2SID_DEV_SHIFT 3
> +#define PORT_RID2SID_FUNC_SHIFT 0
> +#define PORT_OUTS_PREQS_HDR 0x00980
> +#define PORT_OUTS_PREQS_HDR_MASK GENMASK(9, 0)
> +#define PORT_OUTS_PREQS_DATA 0x00984
> +#define PORT_OUTS_PREQS_DATA_MASK GENMASK(15, 0)
> +#define PORT_TUNCTRL 0x00988
> +#define PORT_TUNCTRL_PERST_ON BIT(0)
> +#define PORT_TUNCTRL_PERST_ACK_REQ BIT(1)
> +#define PORT_TUNSTAT 0x0098c
> +#define PORT_TUNSTAT_PERST_ON BIT(0)
> +#define PORT_TUNSTAT_PERST_ACK_PEND BIT(1)
> +#define PORT_PREFMEM_ENABLE 0x00994
> +
> +/* The doorbell address is "well known" */
> +#define DOORBELL_ADDR 0xfffff000
> +
> +struct apple_pcie {
> + struct mutex lock;
> + struct device *dev;
> + void __iomem *rc;
> +};
> +
> +static inline void rmwl(u32 clr, u32 set, void __iomem *addr)
> +{
> + writel_relaxed((readl_relaxed(addr) & ~clr) | set, addr);
> +}
> +
> +static int apple_pcie_setup_port(struct apple_pcie *pcie,
> + struct gpio_desc *reset,
> + unsigned int i)
> +{
> + struct platform_device *platform = to_platform_device(pcie->dev);
> + void __iomem *port;
> + uint32_t stat;
> + int ret;
> +
> + port = devm_platform_ioremap_resource(platform, i + 2);
> +
> + if (IS_ERR(port))
> + return -ENODEV;
> +
> + /* Skip setup if the link was already enabled by the bootloader */
> + if (readl_relaxed(port + PORT_LINKSTS) & PORT_LINKSTS_UP)
> + return 0;
> +
> + rmwl(0, PORT_PERST_OFF, port + PORT_PERST);
> + gpiod_set_value(reset, 1);
> +
> + ret = readl_relaxed_poll_timeout(port + PORT_STATUS, stat,
> + stat & PORT_STATUS_READY, 100, 250000);
> + if (ret < 0) {
> + dev_err(pcie->dev, "port %u ready wait timeout\n", i);
> + return ret;
> + }
> +
> + /* Configure MSIs */
> + writel_relaxed(DOORBELL_ADDR, port + PORT_MSIADDR);
> + writel_relaxed(0, port + PORT_MSIBASE);
> +
> + /* Enable 32 MSIs */
> + writel_relaxed((5 << PORT_MSICFG_L2MSINUM_SHIFT) | PORT_MSICFG_EN,
> + port + PORT_MSICFG);

The MSI configuration writes should probably be part of patch 4/6.

> +
> + /* Enable link interrupts */
> + writel_relaxed(0xfb512fff, port + PORT_INTMSKSET);

So this magic number should probably be the bitwise inverse of the
value used below:

> +
> + writel_relaxed(PORT_INT_LINK_UP | PORT_INT_LINK_DOWN |
> + PORT_INT_AF_TIMEOUT | PORT_INT_REQADDR_GT32 |
> + PORT_INT_MSI_ERR | PORT_INT_MSI_BAD_DATA |
> + PORT_INT_CPL_ABORT | PORT_INT_CPL_TIMEOUT | (1 << 26),
> + port + PORT_INTSTAT);

My suggestion would be to introduce a #define PORT_INT_DEFAULT for
that collection of bits and use ~PORT_INT_DEFAULT in the first write
and PORT_INT_DEFAULT in the latter.

Wonder if we can figure out what bit 26 means. Or maybe we don't
really need to enable that interrupt and can forget about it? The
Corellium code doesn't handle that bit in its interrupt handler, so
unless there is some magic going on we should be able to simply ignore
it.

> +
> + /* Flush writes and enable the link */
> + dma_wmb();
> + writel_relaxed(PORT_LTSSMCTL_START, port + PORT_LTSSMCTL);
> +
> + return 0;
> +}
> +
> +static int apple_m1_pci_init(struct pci_config_window *cfg)
> +{
> + struct device *dev = cfg->parent;
> + struct platform_device *platform = to_platform_device(dev);
> +
> + struct apple_pcie *pcie;
> + struct device_node *of_port;
> + int ret, i;
> +
> + pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> + if (!pcie)
> + return -ENOMEM;
> +
> + pcie->dev = dev;
> +
> + mutex_init(&pcie->lock);
> +
> + pcie->rc = devm_platform_ioremap_resource(platform, 1);
> +
> + if (IS_ERR(pcie->rc))
> + return -ENODEV;
> +
> + i = 0;
> +
> + for_each_child_of_node(dev->of_node, of_port) {
> + struct gpio_desc *reset;
> +
> + reset = gpiod_get_from_of_node(of_port, "reset-gpios", 0,
> + GPIOD_OUT_LOW, "#PERST");
> + if (IS_ERR(reset))
> + return PTR_ERR(reset);
> +
> + ret = apple_pcie_setup_port(pcie, reset, i);
> +
> + if (ret) {
> + dev_err(pcie->dev, "Port %u setup fail: %d\n", i, ret);
> + return ret;
> + }
> +
> + ++i;
> + }
> +
> + return 0;
> +}
> +
> +static const struct pci_ecam_ops apple_m1_cfg_ecam_ops = {
> + .init = apple_m1_pci_init,
> + .pci_ops = {
> + .map_bus = pci_ecam_map_bus,
> + .read = pci_generic_config_read,
> + .write = pci_generic_config_write,
> + }
> +};
> +
> +static const struct of_device_id apple_pci_of_match[] = {
> + { .compatible = "apple,pcie", .data = &apple_m1_cfg_ecam_ops },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, apple_pci_of_match);
> +
> +static struct platform_driver apple_pci_driver = {
> + .driver = {
> + .name = "pcie-apple",
> + .of_match_table = apple_pci_of_match,
> + },
> + .probe = pci_host_common_probe,
> + .remove = pci_host_common_remove,
> +};
> +module_platform_driver(apple_pci_driver);
> +
> +MODULE_LICENSE("GPL v2");
> --
> 2.30.2
>
>

Next message: Christophe JAILLET: "[PATCH] x86/PCI: sta2x11: switch from 'pci_' to 'dma_' API"
Previous message: Dmitry Osipenko: "Re: [PATCH v8 01/34] opp: Add dev_pm_opp_sync() helper"
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