drivers/pci/host/pci-thunder-pem.c - kernel/quantenna - Git at Google

 /*
  * 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.
  *
  * 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/>.
  *
  * Copyright (C) 2015 - 2016 Cavium, Inc.
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/of_pci.h>
 #include <linux/platform_device.h>

 #include "../ecam.h"

 #define PEM_CFG_WR 0x28
 #define PEM_CFG_RD 0x30

 struct thunder_pem_pci {
 	u32		ea_entry[3];
 	void __iomem	*pem_reg_base;
 };

 static int thunder_pem_bridge_read(struct pci_bus *bus, unsigned int devfn,
 				   int where, int size, u32 *val)
 {
 	u64 read_val;
 	struct pci_config_window *cfg = bus->sysdata;
 	struct thunder_pem_pci *pem_pci = (struct thunder_pem_pci *)cfg->priv;

 	if (devfn != 0 || where >= 2048) {
 		*val = ~0;
 		return PCIBIOS_DEVICE_NOT_FOUND;
 	}

 	/*
 	 * 32-bit accesses only.  Write the address to the low order
 	 * bits of PEM_CFG_RD, then trigger the read by reading back.
 	 * The config data lands in the upper 32-bits of PEM_CFG_RD.
 	 */
 	read_val = where & ~3ull;
 	writeq(read_val, pem_pci->pem_reg_base + PEM_CFG_RD);
 	read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
 	read_val >>= 32;

 	/*
 	 * The config space contains some garbage, fix it up.  Also
 	 * synthesize an EA capability for the BAR used by MSI-X.
 	 */
 	switch (where & ~3) {
 	case 0x40:
 		read_val &= 0xffff00ff;
 		read_val |= 0x00007000; /* Skip MSI CAP */
 		break;
 	case 0x70: /* Express Cap */
 		/* PME interrupt on vector 2*/
 		read_val |= (2u << 25);
 		break;
 	case 0xb0: /* MSI-X Cap */
 		/* TableSize=4, Next Cap is EA */
 		read_val &= 0xc00000ff;
 		read_val |= 0x0003bc00;
 		break;
 	case 0xb4:
 		/* Table offset=0, BIR=0 */
 		read_val = 0x00000000;
 		break;
 	case 0xb8:
 		/* BPA offset=0xf0000, BIR=0 */
 		read_val = 0x000f0000;
 		break;
 	case 0xbc:
 		/* EA, 1 entry, no next Cap */
 		read_val = 0x00010014;
 		break;
 	case 0xc0:
 		/* DW2 for type-1 */
 		read_val = 0x00000000;
 		break;
 	case 0xc4:
 		/* Entry BEI=0, PP=0x00, SP=0xff, ES=3 */
 		read_val = 0x80ff0003;
 		break;
 	case 0xc8:
 		read_val = pem_pci->ea_entry[0];
 		break;
 	case 0xcc:
 		read_val = pem_pci->ea_entry[1];
 		break;
 	case 0xd0:
 		read_val = pem_pci->ea_entry[2];
 		break;
 	default:
 		break;
 	}
 	read_val >>= (8 * (where & 3));
 	switch (size) {
 	case 1:
 		read_val &= 0xff;
 		break;
 	case 2:
 		read_val &= 0xffff;
 		break;
 	default:
 		break;
 	}
 	*val = read_val;
 	return PCIBIOS_SUCCESSFUL;
 }

 static int thunder_pem_config_read(struct pci_bus *bus, unsigned int devfn,
 				   int where, int size, u32 *val)
 {
 	struct pci_config_window *cfg = bus->sysdata;

 	if (bus->number < cfg->busr.start ||
 	    bus->number > cfg->busr.end)
 		return PCIBIOS_DEVICE_NOT_FOUND;

 	/*
 	 * The first device on the bus is the PEM PCIe bridge.
 	 * Special case its config access.
 	 */
 	if (bus->number == cfg->busr.start)
 		return thunder_pem_bridge_read(bus, devfn, where, size, val);

 	return pci_generic_config_read(bus, devfn, where, size, val);
 }

 /*
  * Some of the w1c_bits below also include read-only or non-writable
  * reserved bits, this makes the code simpler and is OK as the bits
  * are not affected by writing zeros to them.
  */
 static u32 thunder_pem_bridge_w1c_bits(u64 where_aligned)
 {
 	u32 w1c_bits = 0;

 	switch (where_aligned) {
 	case 0x04: /* Command/Status */
 	case 0x1c: /* Base and I/O Limit/Secondary Status */
 		w1c_bits = 0xff000000;
 		break;
 	case 0x44: /* Power Management Control and Status */
 		w1c_bits = 0xfffffe00;
 		break;
 	case 0x78: /* Device Control/Device Status */
 	case 0x80: /* Link Control/Link Status */
 	case 0x88: /* Slot Control/Slot Status */
 	case 0x90: /* Root Status */
 	case 0xa0: /* Link Control 2 Registers/Link Status 2 */
 		w1c_bits = 0xffff0000;
 		break;
 	case 0x104: /* Uncorrectable Error Status */
 	case 0x110: /* Correctable Error Status */
 	case 0x130: /* Error Status */
 	case 0x160: /* Link Control 4 */
 		w1c_bits = 0xffffffff;
 		break;
 	default:
 		break;
 	}
 	return w1c_bits;
 }

 /* Some bits must be written to one so they appear to be read-only. */
 static u32 thunder_pem_bridge_w1_bits(u64 where_aligned)
 {
 	u32 w1_bits;

 	switch (where_aligned) {
 	case 0x1c: /* I/O Base / I/O Limit, Secondary Status */
 		/* Force 32-bit I/O addressing. */
 		w1_bits = 0x0101;
 		break;
 	case 0x24: /* Prefetchable Memory Base / Prefetchable Memory Limit */
 		/* Force 64-bit addressing */
 		w1_bits = 0x00010001;
 		break;
 	default:
 		w1_bits = 0;
 		break;
 	}
 	return w1_bits;
 }

 static int thunder_pem_bridge_write(struct pci_bus *bus, unsigned int devfn,
 				    int where, int size, u32 val)
 {
 	struct pci_config_window *cfg = bus->sysdata;
 	struct thunder_pem_pci *pem_pci = (struct thunder_pem_pci *)cfg->priv;
 	u64 write_val, read_val;
 	u64 where_aligned = where & ~3ull;
 	u32 mask = 0;


 	if (devfn != 0 || where >= 2048)
 		return PCIBIOS_DEVICE_NOT_FOUND;

 	/*
 	 * 32-bit accesses only.  If the write is for a size smaller
 	 * than 32-bits, we must first read the 32-bit value and merge
 	 * in the desired bits and then write the whole 32-bits back
 	 * out.
 	 */
 	switch (size) {
 	case 1:
 		writeq(where_aligned, pem_pci->pem_reg_base + PEM_CFG_RD);
 		read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
 		read_val >>= 32;
 		mask = ~(0xff << (8 * (where & 3)));
 		read_val &= mask;
 		val = (val & 0xff) << (8 * (where & 3));
 		val |= (u32)read_val;
 		break;
 	case 2:
 		writeq(where_aligned, pem_pci->pem_reg_base + PEM_CFG_RD);
 		read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
 		read_val >>= 32;
 		mask = ~(0xffff << (8 * (where & 3)));
 		read_val &= mask;
 		val = (val & 0xffff) << (8 * (where & 3));
 		val |= (u32)read_val;
 		break;
 	default:
 		break;
 	}

 	/*
 	 * By expanding the write width to 32 bits, we may
 	 * inadvertently hit some W1C bits that were not intended to
 	 * be written.  Calculate the mask that must be applied to the
 	 * data to be written to avoid these cases.
 	 */
 	if (mask) {
 		u32 w1c_bits = thunder_pem_bridge_w1c_bits(where);

 		if (w1c_bits) {
 			mask &= w1c_bits;
 			val &= ~mask;
 		}
 	}

 	/*
 	 * Some bits must be read-only with value of one.  Since the
 	 * access method allows these to be cleared if a zero is
 	 * written, force them to one before writing.
 	 */
 	val |= thunder_pem_bridge_w1_bits(where_aligned);

 	/*
 	 * Low order bits are the config address, the high order 32
 	 * bits are the data to be written.
 	 */
 	write_val = (((u64)val) << 32) | where_aligned;
 	writeq(write_val, pem_pci->pem_reg_base + PEM_CFG_WR);
 	return PCIBIOS_SUCCESSFUL;
 }

 static int thunder_pem_config_write(struct pci_bus *bus, unsigned int devfn,
 				    int where, int size, u32 val)
 {
 	struct pci_config_window *cfg = bus->sysdata;

 	if (bus->number < cfg->busr.start ||
 	    bus->number > cfg->busr.end)
 		return PCIBIOS_DEVICE_NOT_FOUND;
 	/*
 	 * The first device on the bus is the PEM PCIe bridge.
 	 * Special case its config access.
 	 */
 	if (bus->number == cfg->busr.start)
 		return thunder_pem_bridge_write(bus, devfn, where, size, val);


 	return pci_generic_config_write(bus, devfn, where, size, val);
 }

 static int thunder_pem_init(struct device *dev, struct pci_config_window *cfg)
 {
 	resource_size_t bar4_start;
 	struct resource *res_pem;
 	struct thunder_pem_pci *pem_pci;
 	struct platform_device *pdev;

 	/* Only OF support for now */
 	if (!dev->of_node)
 		return -EINVAL;

 	pem_pci = devm_kzalloc(dev, sizeof(*pem_pci), GFP_KERNEL);
 	if (!pem_pci)
 		return -ENOMEM;

 	pdev = to_platform_device(dev);

 	/*
 	 * The second register range is the PEM bridge to the PCIe
 	 * bus.  It has a different config access method than those
 	 * devices behind the bridge.
 	 */
 	res_pem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 	if (!res_pem) {
 		dev_err(dev, "missing \"reg[1]\"property\n");
 		return -EINVAL;
 	}

 	pem_pci->pem_reg_base = devm_ioremap(dev, res_pem->start, 0x10000);
 	if (!pem_pci->pem_reg_base)
 		return -ENOMEM;

 	/*
 	 * The MSI-X BAR for the PEM and AER interrupts is located at
 	 * a fixed offset from the PEM register base.  Generate a
 	 * fragment of the synthesized Enhanced Allocation capability
 	 * structure here for the BAR.
 	 */
 	bar4_start = res_pem->start + 0xf00000;
 	pem_pci->ea_entry[0] = (u32)bar4_start | 2;
 	pem_pci->ea_entry[1] = (u32)(res_pem->end - bar4_start) & ~3u;
 	pem_pci->ea_entry[2] = (u32)(bar4_start >> 32);

 	cfg->priv = pem_pci;
 	return 0;
 }

 static struct pci_ecam_ops pci_thunder_pem_ops = {
 	.bus_shift	= 24,
 	.init		= thunder_pem_init,
 	.pci_ops	= {
 		.map_bus	= pci_ecam_map_bus,
 		.read		= thunder_pem_config_read,
 		.write		= thunder_pem_config_write,
 	}
 };

 static const struct of_device_id thunder_pem_of_match[] = {
 	{ .compatible = "cavium,pci-host-thunder-pem" },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, thunder_pem_of_match);

 static int thunder_pem_probe(struct platform_device *pdev)
 {
 	return pci_host_common_probe(pdev, &pci_thunder_pem_ops);
 }

 static struct platform_driver thunder_pem_driver = {
 	.driver = {
 		.name = KBUILD_MODNAME,
 		.of_match_table = thunder_pem_of_match,
 	},
 	.probe = thunder_pem_probe,
 };
 module_platform_driver(thunder_pem_driver);

 MODULE_DESCRIPTION("Thunder PEM PCIe host driver");
 MODULE_LICENSE("GPL v2");
	/*
	* 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.
	*
	* 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/>.
	*
	* Copyright (C) 2015 - 2016 Cavium, Inc.
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of_address.h>
	#include <linux/of_pci.h>
	#include <linux/platform_device.h>

	#include "../ecam.h"

	#define PEM_CFG_WR 0x28
	#define PEM_CFG_RD 0x30

	struct thunder_pem_pci {
	u32 ea_entry[3];
	void __iomem *pem_reg_base;
	};

	static int thunder_pem_bridge_read(struct pci_bus *bus, unsigned int devfn,
	int where, int size, u32 *val)
	{
	u64 read_val;
	struct pci_config_window *cfg = bus->sysdata;
	struct thunder_pem_pci pem_pci = (struct thunder_pem_pci )cfg->priv;

	if (devfn != 0 \|\| where >= 2048) {
	*val = ~0;
	return PCIBIOS_DEVICE_NOT_FOUND;
	}

	/*
	* 32-bit accesses only. Write the address to the low order
	* bits of PEM_CFG_RD, then trigger the read by reading back.
	* The config data lands in the upper 32-bits of PEM_CFG_RD.
	*/
	read_val = where & ~3ull;
	writeq(read_val, pem_pci->pem_reg_base + PEM_CFG_RD);
	read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
	read_val >>= 32;

	/*
	* The config space contains some garbage, fix it up. Also
	* synthesize an EA capability for the BAR used by MSI-X.
	*/
	switch (where & ~3) {
	case 0x40:
	read_val &= 0xffff00ff;
	read_val \|= 0x00007000; /* Skip MSI CAP */
	break;
	case 0x70: /* Express Cap */
	/* PME interrupt on vector 2*/
	read_val \|= (2u << 25);
	break;
	case 0xb0: /* MSI-X Cap */
	/* TableSize=4, Next Cap is EA */
	read_val &= 0xc00000ff;
	read_val \|= 0x0003bc00;
	break;
	case 0xb4:
	/* Table offset=0, BIR=0 */
	read_val = 0x00000000;
	break;
	case 0xb8:
	/* BPA offset=0xf0000, BIR=0 */
	read_val = 0x000f0000;
	break;
	case 0xbc:
	/* EA, 1 entry, no next Cap */
	read_val = 0x00010014;
	break;
	case 0xc0:
	/* DW2 for type-1 */
	read_val = 0x00000000;
	break;
	case 0xc4:
	/* Entry BEI=0, PP=0x00, SP=0xff, ES=3 */
	read_val = 0x80ff0003;
	break;
	case 0xc8:
	read_val = pem_pci->ea_entry[0];
	break;
	case 0xcc:
	read_val = pem_pci->ea_entry[1];
	break;
	case 0xd0:
	read_val = pem_pci->ea_entry[2];
	break;
	default:
	break;
	}
	read_val >>= (8 * (where & 3));
	switch (size) {
	case 1:
	read_val &= 0xff;
	break;
	case 2:
	read_val &= 0xffff;
	break;
	default:
	break;
	}
	*val = read_val;
	return PCIBIOS_SUCCESSFUL;
	}

	static int thunder_pem_config_read(struct pci_bus *bus, unsigned int devfn,
	int where, int size, u32 *val)
	{
	struct pci_config_window *cfg = bus->sysdata;

	if (bus->number < cfg->busr.start \|\|
	bus->number > cfg->busr.end)
	return PCIBIOS_DEVICE_NOT_FOUND;

	/*
	* The first device on the bus is the PEM PCIe bridge.
	* Special case its config access.
	*/
	if (bus->number == cfg->busr.start)
	return thunder_pem_bridge_read(bus, devfn, where, size, val);

	return pci_generic_config_read(bus, devfn, where, size, val);
	}

	/*
	* Some of the w1c_bits below also include read-only or non-writable
	* reserved bits, this makes the code simpler and is OK as the bits
	* are not affected by writing zeros to them.
	*/
	static u32 thunder_pem_bridge_w1c_bits(u64 where_aligned)
	{
	u32 w1c_bits = 0;

	switch (where_aligned) {
	case 0x04: /* Command/Status */
	case 0x1c: /* Base and I/O Limit/Secondary Status */
	w1c_bits = 0xff000000;
	break;
	case 0x44: /* Power Management Control and Status */
	w1c_bits = 0xfffffe00;
	break;
	case 0x78: /* Device Control/Device Status */
	case 0x80: /* Link Control/Link Status */
	case 0x88: /* Slot Control/Slot Status */
	case 0x90: /* Root Status */
	case 0xa0: /* Link Control 2 Registers/Link Status 2 */
	w1c_bits = 0xffff0000;
	break;
	case 0x104: /* Uncorrectable Error Status */
	case 0x110: /* Correctable Error Status */
	case 0x130: /* Error Status */
	case 0x160: /* Link Control 4 */
	w1c_bits = 0xffffffff;
	break;
	default:
	break;
	}
	return w1c_bits;
	}

	/* Some bits must be written to one so they appear to be read-only. */
	static u32 thunder_pem_bridge_w1_bits(u64 where_aligned)
	{
	u32 w1_bits;

	switch (where_aligned) {
	case 0x1c: /* I/O Base / I/O Limit, Secondary Status */
	/* Force 32-bit I/O addressing. */
	w1_bits = 0x0101;
	break;
	case 0x24: /* Prefetchable Memory Base / Prefetchable Memory Limit */
	/* Force 64-bit addressing */
	w1_bits = 0x00010001;
	break;
	default:
	w1_bits = 0;
	break;
	}
	return w1_bits;
	}

	static int thunder_pem_bridge_write(struct pci_bus *bus, unsigned int devfn,
	int where, int size, u32 val)
	{
	struct pci_config_window *cfg = bus->sysdata;
	struct thunder_pem_pci pem_pci = (struct thunder_pem_pci )cfg->priv;
	u64 write_val, read_val;
	u64 where_aligned = where & ~3ull;
	u32 mask = 0;


	if (devfn != 0 \|\| where >= 2048)
	return PCIBIOS_DEVICE_NOT_FOUND;

	/*
	* 32-bit accesses only. If the write is for a size smaller
	* than 32-bits, we must first read the 32-bit value and merge
	* in the desired bits and then write the whole 32-bits back
	* out.
	*/
	switch (size) {
	case 1:
	writeq(where_aligned, pem_pci->pem_reg_base + PEM_CFG_RD);
	read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
	read_val >>= 32;
	mask = ~(0xff << (8 * (where & 3)));
	read_val &= mask;
	val = (val & 0xff) << (8 * (where & 3));
	val \|= (u32)read_val;
	break;
	case 2:
	writeq(where_aligned, pem_pci->pem_reg_base + PEM_CFG_RD);
	read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
	read_val >>= 32;
	mask = ~(0xffff << (8 * (where & 3)));
	read_val &= mask;
	val = (val & 0xffff) << (8 * (where & 3));
	val \|= (u32)read_val;
	break;
	default:
	break;
	}

	/*
	* By expanding the write width to 32 bits, we may
	* inadvertently hit some W1C bits that were not intended to
	* be written. Calculate the mask that must be applied to the
	* data to be written to avoid these cases.
	*/
	if (mask) {
	u32 w1c_bits = thunder_pem_bridge_w1c_bits(where);

	if (w1c_bits) {
	mask &= w1c_bits;
	val &= ~mask;
	}
	}

	/*
	* Some bits must be read-only with value of one. Since the
	* access method allows these to be cleared if a zero is
	* written, force them to one before writing.
	*/
	val \|= thunder_pem_bridge_w1_bits(where_aligned);

	/*
	* Low order bits are the config address, the high order 32
	* bits are the data to be written.
	*/
	write_val = (((u64)val) << 32) \| where_aligned;
	writeq(write_val, pem_pci->pem_reg_base + PEM_CFG_WR);
	return PCIBIOS_SUCCESSFUL;
	}

	static int thunder_pem_config_write(struct pci_bus *bus, unsigned int devfn,
	int where, int size, u32 val)
	{
	struct pci_config_window *cfg = bus->sysdata;

	if (bus->number < cfg->busr.start \|\|
	bus->number > cfg->busr.end)
	return PCIBIOS_DEVICE_NOT_FOUND;
	/*
	* The first device on the bus is the PEM PCIe bridge.
	* Special case its config access.
	*/
	if (bus->number == cfg->busr.start)
	return thunder_pem_bridge_write(bus, devfn, where, size, val);


	return pci_generic_config_write(bus, devfn, where, size, val);
	}

	static int thunder_pem_init(struct device dev, struct pci_config_window cfg)
	{
	resource_size_t bar4_start;
	struct resource *res_pem;
	struct thunder_pem_pci *pem_pci;
	struct platform_device *pdev;

	/* Only OF support for now */
	if (!dev->of_node)
	return -EINVAL;

	pem_pci = devm_kzalloc(dev, sizeof(*pem_pci), GFP_KERNEL);
	if (!pem_pci)
	return -ENOMEM;

	pdev = to_platform_device(dev);

	/*
	* The second register range is the PEM bridge to the PCIe
	* bus. It has a different config access method than those
	* devices behind the bridge.
	*/
	res_pem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
	if (!res_pem) {
	dev_err(dev, "missing \"reg[1]\"property\n");
	return -EINVAL;
	}

	pem_pci->pem_reg_base = devm_ioremap(dev, res_pem->start, 0x10000);
	if (!pem_pci->pem_reg_base)
	return -ENOMEM;

	/*
	* The MSI-X BAR for the PEM and AER interrupts is located at
	* a fixed offset from the PEM register base. Generate a
	* fragment of the synthesized Enhanced Allocation capability
	* structure here for the BAR.
	*/
	bar4_start = res_pem->start + 0xf00000;
	pem_pci->ea_entry[0] = (u32)bar4_start \| 2;
	pem_pci->ea_entry[1] = (u32)(res_pem->end - bar4_start) & ~3u;
	pem_pci->ea_entry[2] = (u32)(bar4_start >> 32);

	cfg->priv = pem_pci;
	return 0;
	}

	static struct pci_ecam_ops pci_thunder_pem_ops = {
	.bus_shift = 24,
	.init = thunder_pem_init,
	.pci_ops = {
	.map_bus = pci_ecam_map_bus,
	.read = thunder_pem_config_read,
	.write = thunder_pem_config_write,
	}
	};

	static const struct of_device_id thunder_pem_of_match[] = {
	{ .compatible = "cavium,pci-host-thunder-pem" },
	{ },
	};
	MODULE_DEVICE_TABLE(of, thunder_pem_of_match);

	static int thunder_pem_probe(struct platform_device *pdev)
	{
	return pci_host_common_probe(pdev, &pci_thunder_pem_ops);
	}

	static struct platform_driver thunder_pem_driver = {
	.driver = {
	.name = KBUILD_MODNAME,
	.of_match_table = thunder_pem_of_match,
	},
	.probe = thunder_pem_probe,
	};
	module_platform_driver(thunder_pem_driver);

	MODULE_DESCRIPTION("Thunder PEM PCIe host driver");
	MODULE_LICENSE("GPL v2");