Re: [PATCH v2 10/13] MIPS: ath25: add AR2315 PCI host controller driver

[John Crispin <blogic@openwrt.org>]

On 22/10/2014 01:03, Sergey Ryazanov wrote:
> Add PCI host controller driver and DMA address calculation hook.
> 
> Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
> ---
> 
> Changes since RFC:
>   - use dynamic IRQ numbers allocation
> 
> Changes since v1:
>   - rename MIPS machine ar231x -> ath25
> 
>  arch/mips/ath25/Kconfig                          |   7 +
>  arch/mips/ath25/ar2315.c                         |   9 +
>  arch/mips/include/asm/mach-ath25/ar2315_regs.h   |  23 ++
>  arch/mips/include/asm/mach-ath25/dma-coherence.h |  18 +-
>  arch/mips/pci/Makefile                           |   1 +
>  arch/mips/pci/pci-ar2315.c                       | 352 +++++++++++++++++++++++
>  6 files changed, 407 insertions(+), 3 deletions(-)
>  create mode 100644 arch/mips/pci/pci-ar2315.c
> 
> diff --git a/arch/mips/ath25/Kconfig b/arch/mips/ath25/Kconfig
> index 7bcdbf3..c83b70d 100644
> --- a/arch/mips/ath25/Kconfig
> +++ b/arch/mips/ath25/Kconfig
> @@ -9,3 +9,10 @@ config SOC_AR2315
>  	depends on ATH25
>  	select GPIO_AR2315
>  	default y
> +
> +config PCI_AR2315
> +	bool "Atheros AR2315 PCI controller support"
> +	depends on SOC_AR2315
> +	select HW_HAS_PCI
> +	select PCI
> +	default y
> diff --git a/arch/mips/ath25/ar2315.c b/arch/mips/ath25/ar2315.c
> index ac784d7..76679c0 100644
> --- a/arch/mips/ath25/ar2315.c
> +++ b/arch/mips/ath25/ar2315.c
> @@ -108,6 +108,10 @@ static void ar2315_irq_dispatch(void)
>  
>  	if (pending & CAUSEF_IP3)
>  		do_IRQ(AR2315_IRQ_WLAN0);
> +#ifdef CONFIG_PCI_AR2315
> +	else if (pending & CAUSEF_IP5)
> +		do_IRQ(AR2315_IRQ_LCBUS_PCI);
> +#endif
>  	else if (pending & CAUSEF_IP2)
>  		do_IRQ(AR2315_IRQ_MISC);
>  	else if (pending & CAUSEF_IP7)
> @@ -353,5 +357,10 @@ void __init ar2315_arch_init(void)
>  {
>  	ath25_serial_setup(AR2315_UART0, ar2315_misc_irq_base +
>  			   AR2315_MISC_IRQ_UART0, ar2315_apb_frequency());
> +
> +#ifdef CONFIG_PCI_AR2315
> +	if (ath25_soc == ATH25_SOC_AR2315)
> +		platform_device_register_simple("ar2315-pci", -1, NULL, 0);
> +#endif
>  }
>  
> diff --git a/arch/mips/include/asm/mach-ath25/ar2315_regs.h b/arch/mips/include/asm/mach-ath25/ar2315_regs.h
> index d61c8a1..e732b9a 100644
> --- a/arch/mips/include/asm/mach-ath25/ar2315_regs.h
> +++ b/arch/mips/include/asm/mach-ath25/ar2315_regs.h
> @@ -38,6 +38,15 @@
>  #define AR2315_MISC_IRQ_COUNT		9
>  
>  /*
> + * PCI interrupts, which share IP5
> + * Keep ordered according to AR2315_PCI_INT_XXX bits
> + */
> +#define AR2315_PCI_IRQ_EXT		0
> +#define AR2315_PCI_IRQ_ABORT		1
> +#define AR2315_PCI_IRQ_COUNT		2
> +#define AR2315_PCI_IRQ_SHIFT		25	/* in AR2315_PCI_INT_STATUS */
> +
> +/*
>   * Address map
>   */
>  #define AR2315_SPI_READ		0x08000000	/* SPI flash */
> @@ -554,4 +563,18 @@
>  #define AR2315_IRCFG_SEQ_END_WIN_THRESH	0x001f0000
>  #define AR2315_IRCFG_NUM_BACKOFF_WORDS	0x01e00000
>  
> +/*
> + * We need some arbitrary non-zero value to be programmed to the BAR1 register
> + * of PCI host controller to enable DMA. The same value should be used as the
> + * offset to calculate the physical address of DMA buffer for PCI devices.
> + */
> +#define AR2315_PCI_HOST_SDRAM_BASEADDR	0x20000000
> +
> +/* ??? access BAR */
> +#define AR2315_PCI_HOST_MBAR0		0x10000000
> +/* RAM access BAR */
> +#define AR2315_PCI_HOST_MBAR1		AR2315_PCI_HOST_SDRAM_BASEADDR
> +/* ??? access BAR */
> +#define AR2315_PCI_HOST_MBAR2		0x30000000
> +
>  #endif /* __ASM_MACH_ATH25_AR2315_REGS_H */
> diff --git a/arch/mips/include/asm/mach-ath25/dma-coherence.h b/arch/mips/include/asm/mach-ath25/dma-coherence.h
> index 8b3d0cc..063c1ca 100644
> --- a/arch/mips/include/asm/mach-ath25/dma-coherence.h
> +++ b/arch/mips/include/asm/mach-ath25/dma-coherence.h
> @@ -11,23 +11,35 @@
>  #define __ASM_MACH_ATH25_DMA_COHERENCE_H
>  
>  #include <linux/device.h>
> +#include <ar2315_regs.h>
> +
> +static inline dma_addr_t ath25_dev_offset(struct device *dev)
> +{
> +#ifdef CONFIG_PCI
> +	extern struct bus_type pci_bus_type;
> +
> +	if (dev && dev->bus == &pci_bus_type)
> +		return AR2315_PCI_HOST_SDRAM_BASEADDR;
> +#endif
> +	return 0;
> +}
>  
>  static inline dma_addr_t
>  plat_map_dma_mem(struct device *dev, void *addr, size_t size)
>  {
> -	return virt_to_phys(addr);
> +	return virt_to_phys(addr) + ath25_dev_offset(dev);
>  }
>  
>  static inline dma_addr_t
>  plat_map_dma_mem_page(struct device *dev, struct page *page)
>  {
> -	return page_to_phys(page);
> +	return page_to_phys(page) + ath25_dev_offset(dev);
>  }
>  
>  static inline unsigned long
>  plat_dma_addr_to_phys(struct device *dev, dma_addr_t dma_addr)
>  {
> -	return dma_addr;
> +	return dma_addr - ath25_dev_offset(dev);
>  }
>  
>  static inline void
> diff --git a/arch/mips/pci/Makefile b/arch/mips/pci/Makefile
> index 6523d55..ab6c857 100644
> --- a/arch/mips/pci/Makefile
> +++ b/arch/mips/pci/Makefile
> @@ -19,6 +19,7 @@ obj-$(CONFIG_BCM47XX)		+= pci-bcm47xx.o
>  obj-$(CONFIG_BCM63XX)		+= pci-bcm63xx.o fixup-bcm63xx.o \
>  					ops-bcm63xx.o
>  obj-$(CONFIG_MIPS_ALCHEMY)	+= pci-alchemy.o
> +obj-$(CONFIG_PCI_AR2315)	+= pci-ar2315.o
>  obj-$(CONFIG_SOC_AR71XX)	+= pci-ar71xx.o
>  obj-$(CONFIG_PCI_AR724X)	+= pci-ar724x.o
>  obj-$(CONFIG_MIPS_PCI_VIRTIO)	+= pci-virtio-guest.o
> diff --git a/arch/mips/pci/pci-ar2315.c b/arch/mips/pci/pci-ar2315.c
> new file mode 100644
> index 0000000..bb6498f
> --- /dev/null
> +++ b/arch/mips/pci/pci-ar2315.c
> @@ -0,0 +1,352 @@
> +/*
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version 2
> + * of the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that 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/>.
> + */
> +
> +/**
> + * Both AR2315 and AR2316 chips have PCI interface unit, which supports DMA
> + * and interrupt. PCI interface supports MMIO access method, but does not
> + * seem to support I/O ports.
> + *
> + * Read/write operation in the region 0x80000000-0xBFFFFFFF causes
> + * a memory read/write command on the PCI bus. 30 LSBs of address on
> + * the bus are taken from memory read/write request and 2 MSBs are
> + * determined by PCI unit configuration.
> + *
> + * To work with the configuration space instead of memory is necessary set
> + * the CFG_SEL bit in the PCI_MISC_CONFIG register.
> + *
> + * Devices on the bus can perform DMA requests via chip BAR1. PCI host
> + * controller BARs are programmend as if an external device is programmed.
> + * Which means that during configuration, IDSEL pin of the chip should be
> + * asserted.
> + *
> + * We know (and support) only one board that uses the PCI interface -
> + * Fonera 2.0g (FON2202). It has a USB EHCI controller connected to the
> + * AR2315 PCI bus. IDSEL pin of USB controller is connected to AD[13] line
> + * and IDSEL pin of AR125 is connected to AD[16] line.
> + */
> +
> +#include <linux/types.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/mm.h>
> +#include <linux/delay.h>
> +#include <linux/irq.h>
> +#include <linux/io.h>
> +#include <asm/paccess.h>
> +#include <ath25.h>
> +#include <ar2315_regs.h>
> +
> +/* Arbitrary size of memory region to access the configuration space */
> +#define AR2315_PCI_CFG_SIZE	0x00100000
> +
> +#define AR2315_PCI_HOST_SLOT	3
> +#define AR2315_PCI_HOST_DEVID	((0xff18 << 16) | PCI_VENDOR_ID_ATHEROS)
> +
> +static void __iomem *ar2315_pci_cfg_mem;
> +static unsigned ar2315_pci_irq_base;
> +
> +static int ar2315_pci_cfg_access(int devfn, int where, int size, u32 *ptr,
> +				 bool write)
> +{
> +	int func = PCI_FUNC(devfn);
> +	int dev = PCI_SLOT(devfn);
> +	u32 addr = (1 << (13 + dev)) | (func << 8) | (where & ~3);
> +	u32 mask = 0xffffffff >> 8 * (4 - size);
> +	u32 sh = (where & 3) * 8;
> +	u32 value, isr;
> +
> +	/* Prevent access past the remapped area */
> +	if (addr >= AR2315_PCI_CFG_SIZE || dev > 18)
> +		return PCIBIOS_DEVICE_NOT_FOUND;
> +
> +	/* Clear pending errors */
> +	ath25_write_reg(AR2315_PCI_ISR, AR2315_PCI_INT_ABORT);
> +	/* Select Configuration access */
> +	ath25_mask_reg(AR2315_PCI_MISC_CONFIG, 0, AR2315_PCIMISC_CFG_SEL);
> +
> +	mb();	/* PCI must see space change before we begin */
> +
> +	value = __raw_readl(ar2315_pci_cfg_mem + addr);
> +
> +	isr = ath25_read_reg(AR2315_PCI_ISR);
> +	if (isr & AR2315_PCI_INT_ABORT)
> +		goto exit_err;
> +
> +	if (write) {
> +		value = (value & ~(mask << sh)) | *ptr << sh;
> +		__raw_writel(value, ar2315_pci_cfg_mem + addr);
> +		isr = ath25_read_reg(AR2315_PCI_ISR);
> +		if (isr & AR2315_PCI_INT_ABORT)
> +			goto exit_err;
> +	} else {
> +		*ptr = (value >> sh) & mask;
> +	}
> +
> +	goto exit;
> +
> +exit_err:
> +	ath25_write_reg(AR2315_PCI_ISR, AR2315_PCI_INT_ABORT);
> +	if (!write)
> +		*ptr = 0xffffffff;
> +
> +exit:
> +	/* Select Memory access */
> +	ath25_mask_reg(AR2315_PCI_MISC_CONFIG, AR2315_PCIMISC_CFG_SEL, 0);
> +
> +	return isr & AR2315_PCI_INT_ABORT ? PCIBIOS_DEVICE_NOT_FOUND :
> +					    PCIBIOS_SUCCESSFUL;
> +}
> +
> +static inline int ar2315_pci_local_cfg_rd(unsigned devfn, int where, u32 *val)
> +{
> +	return ar2315_pci_cfg_access(devfn, where, sizeof(u32), val, false);
> +}
> +
> +static inline int ar2315_pci_local_cfg_wr(unsigned devfn, int where, u32 val)
> +{
> +	return ar2315_pci_cfg_access(devfn, where, sizeof(u32), &val, true);
> +}
> +
> +static int ar2315_pci_cfg_read(struct pci_bus *bus, unsigned int devfn,
> +			       int where, int size, u32 *value)
> +{
> +	if (PCI_SLOT(devfn) == AR2315_PCI_HOST_SLOT)
> +		return PCIBIOS_DEVICE_NOT_FOUND;
> +
> +	return ar2315_pci_cfg_access(devfn, where, size, value, 0);
> +}
> +
> +static int ar2315_pci_cfg_write(struct pci_bus *bus, unsigned int devfn,
> +				int where, int size, u32 value)
> +{
> +	if (PCI_SLOT(devfn) == AR2315_PCI_HOST_SLOT)
> +		return PCIBIOS_DEVICE_NOT_FOUND;
> +
> +	return ar2315_pci_cfg_access(devfn, where, size, &value, 1);
> +}
> +
> +static struct pci_ops ar2315_pci_ops = {
> +	.read	= ar2315_pci_cfg_read,
> +	.write	= ar2315_pci_cfg_write,
> +};
> +
> +static struct resource ar2315_mem_resource = {
> +	.name	= "ar2315-pci-mem",
> +	.start	= AR2315_PCIEXT,
> +	.end	= AR2315_PCIEXT + AR2315_PCIEXT_SZ - 1,
> +	.flags	= IORESOURCE_MEM,
> +};
> +
> +/* PCI controller does not support I/O ports */
> +static struct resource ar2315_io_resource = {
> +	.name	= "ar2315-pci-io",
> +	.start	= 0,
> +	.end	= 0,
> +	.flags	= IORESOURCE_IO,
> +};
> +
> +static struct pci_controller ar2315_pci_controller = {
> +	.pci_ops	= &ar2315_pci_ops,
> +	.mem_resource	= &ar2315_mem_resource,
> +	.io_resource	= &ar2315_io_resource,
> +	.mem_offset     = 0x00000000UL,
> +	.io_offset      = 0x00000000UL,
> +};
> +
> +static int ar2315_pci_host_setup(void)
> +{
> +	unsigned devfn = PCI_DEVFN(AR2315_PCI_HOST_SLOT, 0);
> +	int res;
> +	u32 id;
> +
> +	res = ar2315_pci_local_cfg_rd(devfn, PCI_VENDOR_ID, &id);
> +	if (res != PCIBIOS_SUCCESSFUL || id != AR2315_PCI_HOST_DEVID)
> +		return -ENODEV;
> +
> +	/* Program MBARs */
> +	ar2315_pci_local_cfg_wr(devfn, PCI_BASE_ADDRESS_0,
> +				AR2315_PCI_HOST_MBAR0);
> +	ar2315_pci_local_cfg_wr(devfn, PCI_BASE_ADDRESS_1,
> +				AR2315_PCI_HOST_MBAR1);
> +	ar2315_pci_local_cfg_wr(devfn, PCI_BASE_ADDRESS_2,
> +				AR2315_PCI_HOST_MBAR2);
> +
> +	/* Run */
> +	ar2315_pci_local_cfg_wr(devfn, PCI_COMMAND, PCI_COMMAND_MEMORY |
> +				PCI_COMMAND_MASTER | PCI_COMMAND_SPECIAL |
> +				PCI_COMMAND_INVALIDATE | PCI_COMMAND_PARITY |
> +				PCI_COMMAND_SERR | PCI_COMMAND_FAST_BACK);
> +
> +	return 0;
> +}
> +
> +static void ar2315_pci_irq_handler(unsigned irq, struct irq_desc *desc)
> +{
> +	u32 pending = ath25_read_reg(AR2315_PCI_ISR) &
> +		      ath25_read_reg(AR2315_PCI_IMR);
> +
> +	if (pending & AR2315_PCI_INT_EXT)
> +		generic_handle_irq(ar2315_pci_irq_base + AR2315_PCI_IRQ_EXT);
> +	else if (pending & AR2315_PCI_INT_ABORT)
> +		generic_handle_irq(ar2315_pci_irq_base + AR2315_PCI_IRQ_ABORT);
> +	else
> +		spurious_interrupt();
> +}
> +
> +static void ar2315_pci_irq_mask(struct irq_data *d)
> +{
> +	u32 m = 1 << (d->irq - ar2315_pci_irq_base + AR2315_PCI_IRQ_SHIFT);
> +
> +	ath25_mask_reg(AR2315_PCI_IMR, m, 0);
> +}
> +
> +static void ar2315_pci_irq_mask_ack(struct irq_data *d)
> +{
> +	u32 m = 1 << (d->irq - ar2315_pci_irq_base + AR2315_PCI_IRQ_SHIFT);
> +
> +	ath25_mask_reg(AR2315_PCI_IMR, m, 0);
> +	ath25_write_reg(AR2315_PCI_ISR, m);
> +}
> +
> +static void ar2315_pci_irq_unmask(struct irq_data *d)
> +{
> +	u32 m = 1 << (d->irq - ar2315_pci_irq_base + AR2315_PCI_IRQ_SHIFT);
> +
> +	ath25_mask_reg(AR2315_PCI_IMR, 0, m);
> +}
> +

once you have irqdomain you will need to change these to use d->hwirq
instead of d->irq



> +static struct irq_chip ar2315_pci_irq_chip = {
> +	.name = "AR2315-PCI",
> +	.irq_mask = ar2315_pci_irq_mask,
> +	.irq_mask_ack = ar2315_pci_irq_mask_ack,
> +	.irq_unmask = ar2315_pci_irq_unmask,
> +};
> +
> +static void ar2315_pci_irq_init(void)
> +{
> +	unsigned i;
> +
> +	ath25_mask_reg(AR2315_PCI_IER, AR2315_PCI_IER_ENABLE, 0);
> +	ath25_mask_reg(AR2315_PCI_IMR, (AR2315_PCI_INT_ABORT |
> +			 AR2315_PCI_INT_EXT), 0);
> +
> +	for (i = 0; i < AR2315_PCI_IRQ_COUNT; ++i) {
> +		unsigned irq = ar2315_pci_irq_base + i;
> +
> +		irq_set_chip_and_handler(irq, &ar2315_pci_irq_chip,
> +					 handle_level_irq);
> +	}
> +
> +	irq_set_chained_handler(AR2315_IRQ_LCBUS_PCI, ar2315_pci_irq_handler);
> +
> +	/* Clear any pending Abort or external Interrupts
> +	 * and enable interrupt processing */
> +	ath25_write_reg(AR2315_PCI_ISR, (AR2315_PCI_INT_ABORT |
> +			 AR2315_PCI_INT_EXT));
> +	ath25_mask_reg(AR2315_PCI_IER, 0, AR2315_PCI_IER_ENABLE);
> +}
> +
> +static int ar2315_pci_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	u32 reg;
> +	int res;
> +
> +	/* Remap PCI config space */
> +	ar2315_pci_cfg_mem = devm_ioremap_nocache(dev, AR2315_PCIEXT,
> +						  AR2315_PCI_CFG_SIZE);
> +	if (!ar2315_pci_cfg_mem) {
> +		dev_err(dev, "failed to remap PCI config space\n");
> +		return -ENOMEM;
> +	}
> +
> +	/* Reset PCI DMA logic */
> +	reg = ath25_mask_reg(AR2315_RESET, 0, AR2315_RESET_PCIDMA);
> +	msleep(20);
> +	reg &= ~AR2315_RESET_PCIDMA;
> +	ath25_write_reg(AR2315_RESET, reg);
> +	msleep(20);
> +
> +	ath25_mask_reg(AR2315_ENDIAN_CTL, 0,
> +			AR2315_CONFIG_PCIAHB | AR2315_CONFIG_PCIAHB_BRIDGE);
> +
> +	ath25_write_reg(AR2315_PCICLK, AR2315_PCICLK_PLLC_CLKM |
> +			 (AR2315_PCICLK_IN_FREQ_DIV_6 << AR2315_PCICLK_DIV_S));
> +	ath25_mask_reg(AR2315_AHB_ARB_CTL, 0, AR2315_ARB_PCI);
> +	ath25_mask_reg(AR2315_IF_CTL, AR2315_IF_PCI_CLK_MASK | AR2315_IF_MASK,
> +			AR2315_IF_PCI | AR2315_IF_PCI_HOST |
> +			AR2315_IF_PCI_INTR | (AR2315_IF_PCI_CLK_OUTPUT_CLK <<
> +					      AR2315_IF_PCI_CLK_SHIFT));
> +
> +	/* Reset the PCI bus by setting bits 5-4 in PCI_MCFG */
> +	ath25_mask_reg(AR2315_PCI_MISC_CONFIG, AR2315_PCIMISC_RST_MODE,
> +			AR2315_PCIRST_LOW);
> +	msleep(100);
> +
> +	/* Bring the PCI out of reset */
> +	ath25_mask_reg(AR2315_PCI_MISC_CONFIG, AR2315_PCIMISC_RST_MODE,
> +			AR2315_PCIRST_HIGH | AR2315_PCICACHE_DIS | 0x8);
> +
> +	ath25_write_reg(AR2315_PCI_UNCACHE_CFG,
> +			 0x1E | /* 1GB uncached */
> +			 (1 << 5) | /* Enable uncached */
> +			 (0x2 << 30) /* Base: 0x80000000 */);
> +	ath25_read_reg(AR2315_PCI_UNCACHE_CFG);
> +
> +	msleep(500);
> +
> +	res = ar2315_pci_host_setup();
> +	if (res)
> +		return res;
> +
> +	res = irq_alloc_descs(-1, 0, AR2315_PCI_IRQ_COUNT, 0);
> +	if (res < 0) {
> +		dev_err(dev, "failed to allocate PCI IRQ numbers\n");
> +		return res;
> +	}
> +	ar2315_pci_irq_base = res;
> +
> +	ar2315_pci_irq_init();
> +
> +	register_pci_controller(&ar2315_pci_controller);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver ar2315_pci_driver = {
> +	.probe = ar2315_pci_probe,
> +	.driver = {
> +		.name = "ar2315-pci",
> +		.owner = THIS_MODULE,
> +	},
> +};
> +
> +static int __init ar2315_pci_init(void)
> +{
> +	return platform_driver_register(&ar2315_pci_driver);
> +}
> +arch_initcall(ar2315_pci_init);
> +
> +int pcibios_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
> +{
> +	return ar2315_pci_irq_base + AR2315_PCI_IRQ_EXT;
> +}
> +
> +int pcibios_plat_dev_init(struct pci_dev *dev)
> +{
> +	return 0;
> +}
>