[u-boot.git] / cmd / pci_mps.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2022 Microsoft Corporation <www.microsoft.com>
 * Stephen Carlson <[email protected]>
 *
 * PCI Express Maximum Packet Size (MPS) configuration
 */

#include <common.h>
#include <bootretry.h>
#include <cli.h>
#include <command.h>
#include <console.h>
#include <dm.h>
#include <init.h>
#include <asm/processor.h>
#include <asm/io.h>
#include <pci.h>

#define PCI_MPS_SAFE 0
#define PCI_MPS_PEER2PEER 1

static int pci_mps_find_safe(struct udevice *bus, unsigned int *min_mps,
			     unsigned int *n)
{
	struct udevice *dev;
	int res = 0, addr;
	unsigned int mpss;
	u32 regval;

	if (!min_mps || !n)
		return -EINVAL;

	for (device_find_first_child(bus, &dev);
	     dev;
	     device_find_next_child(&dev)) {
		addr = dm_pci_find_capability(dev, PCI_CAP_ID_EXP);
		if (addr <= 0)
			continue;

		res = dm_pci_read_config32(dev, addr + PCI_EXP_DEVCAP,
					   &regval);
		if (res != 0)
			return res;
		mpss = (unsigned int)(regval & PCI_EXP_DEVCAP_PAYLOAD);
		*n += 1;
		if (mpss < *min_mps)
			*min_mps = mpss;
	}

	return res;
}

static int pci_mps_set_bus(struct udevice *bus, unsigned int target)
{
	struct udevice *dev;
	u32 mpss, target_mps = (u32)(target << 5);
	u16 mps;
	int res = 0, addr;

	for (device_find_first_child(bus, &dev);
	     dev && res == 0;
	     device_find_next_child(&dev)) {
		addr = dm_pci_find_capability(dev, PCI_CAP_ID_EXP);
		if (addr <= 0)
			continue;

		res = dm_pci_read_config32(dev, addr + PCI_EXP_DEVCAP,
					   &mpss);
		if (res != 0)
			return res;

		/* Do not set device above its maximum MPSS */
		mpss = (mpss & PCI_EXP_DEVCAP_PAYLOAD) << 5;
		if (target_mps < mpss)
			mps = (u16)target_mps;
		else
			mps = (u16)mpss;
		res = dm_pci_clrset_config16(dev, addr + PCI_EXP_DEVCTL,
					     PCI_EXP_DEVCTL_PAYLOAD, mps);
	}

	return res;
}

/*
 * Sets the MPS of each PCI Express device to the specified policy.
 */
static int pci_mps_set(int policy)
{
	struct udevice *bus;
	int i, res = 0;
	/* 0 = 128B, min value for hotplug */
	unsigned int mps = 0;

	if (policy == PCI_MPS_SAFE) {
		unsigned int min_mps = PCI_EXP_DEVCAP_PAYLOAD_4096B, n = 0;

		/* Find maximum MPS supported by all devices */
		for (i = 0;
		     uclass_get_device_by_seq(UCLASS_PCI, i, &bus) == 0 &&
		     res == 0;
		     i++)
			res = pci_mps_find_safe(bus, &min_mps, &n);

		/* If no devices were found, do not reconfigure */
		if (n == 0)
			return res;
		mps = min_mps;
	}

	/* This message is checked by the sandbox test */
	printf("Setting MPS of all devices to %uB\n", 128U << mps);
	for (i = 0;
	     uclass_get_device_by_seq(UCLASS_PCI, i, &bus) == 0 && res == 0;
	     i++)
		res = pci_mps_set_bus(bus, mps);

	return res;
}

/*
 * PCI MPS tuning commands
 *
 * Syntax:
 *	pci_mps safe
 *	pci_mps peer2peer
 */
static int do_pci_mps(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
{
	char cmd = 'u';
	int ret = 0;

	if (argc > 1)
		cmd = argv[1][0];

	switch (cmd) {
	case 's':		/* safe */
		ret = pci_mps_set(PCI_MPS_SAFE);
		break;
	case 'p':		/* peer2peer/hotplug */
		ret = pci_mps_set(PCI_MPS_PEER2PEER);
		break;
	default:		/* usage, help */
		goto usage;
	}

	return ret;
usage:
	return CMD_RET_USAGE;
}

/***************************************************/

U_BOOT_LONGHELP(pci_mps,
	"safe\n"
	"    - Set PCI Express MPS of all devices to safe values\n"
	"pci_mps peer2peer\n"
	"    - Set PCI Express MPS of all devices to support hotplug and peer-to-peer DMA\n");

U_BOOT_CMD(pci_mps, 2, 0, do_pci_mps,
	   "configure PCI Express MPS", pci_mps_help_text);
Commit	Line	Data
59b1c9be SC	1	// SPDX-License-Identifier: GPL-2.0+
	2	/*
	3	* (C) Copyright 2022 Microsoft Corporation <www.microsoft.com>
	4	* Stephen Carlson <[email protected]>
	5	*
	6	* PCI Express Maximum Packet Size (MPS) configuration
	7	*/
	8
	9	#include <common.h>
	10	#include <bootretry.h>
	11	#include <cli.h>
	12	#include <command.h>
	13	#include <console.h>
	14	#include <dm.h>
	15	#include <init.h>
	16	#include <asm/processor.h>
	17	#include <asm/io.h>
	18	#include <pci.h>
	19
	20	#define PCI_MPS_SAFE 0
	21	#define PCI_MPS_PEER2PEER 1
	22
	23	static int pci_mps_find_safe(struct udevice bus, unsigned int min_mps,
	24	unsigned int *n)
	25	{
	26	struct udevice *dev;
	27	int res = 0, addr;
	28	unsigned int mpss;
	29	u32 regval;
	30
	31	if (!min_mps \|\| !n)
	32	return -EINVAL;
	33
	34	for (device_find_first_child(bus, &dev);
	35	dev;
	36	device_find_next_child(&dev)) {
	37	addr = dm_pci_find_capability(dev, PCI_CAP_ID_EXP);
	38	if (addr <= 0)
	39	continue;
	40
	41	res = dm_pci_read_config32(dev, addr + PCI_EXP_DEVCAP,
	42	&regval);
	43	if (res != 0)
	44	return res;
	45	mpss = (unsigned int)(regval & PCI_EXP_DEVCAP_PAYLOAD);
	46	*n += 1;
	47	if (mpss < *min_mps)
	48	*min_mps = mpss;
	49	}
	50
	51	return res;
	52	}
	53
	54	static int pci_mps_set_bus(struct udevice *bus, unsigned int target)
	55	{
	56	struct udevice *dev;
	57	u32 mpss, target_mps = (u32)(target << 5);
	58	u16 mps;
	59	int res = 0, addr;
	60
	61	for (device_find_first_child(bus, &dev);
	62	dev && res == 0;
	63	device_find_next_child(&dev)) {
	64	addr = dm_pci_find_capability(dev, PCI_CAP_ID_EXP);
65	if (addr <= 0)
66	continue;
67
68	res = dm_pci_read_config32(dev, addr + PCI_EXP_DEVCAP,
69	&mpss);
70	if (res != 0)
71	return res;
72
73	/* Do not set device above its maximum MPSS */
74	mpss = (mpss & PCI_EXP_DEVCAP_PAYLOAD) << 5;
75	if (target_mps < mpss)
76	mps = (u16)target_mps;
77	else
78	mps = (u16)mpss;
79	res = dm_pci_clrset_config16(dev, addr + PCI_EXP_DEVCTL,
80	PCI_EXP_DEVCTL_PAYLOAD, mps);
81	}
82
83	return res;
84	}
85
86	/*
87	* Sets the MPS of each PCI Express device to the specified policy.
88	*/
89	static int pci_mps_set(int policy)
90	{
91	struct udevice *bus;
92	int i, res = 0;
93	/* 0 = 128B, min value for hotplug */
94	unsigned int mps = 0;
95
96	if (policy == PCI_MPS_SAFE) {
97	unsigned int min_mps = PCI_EXP_DEVCAP_PAYLOAD_4096B, n = 0;
98
99	/* Find maximum MPS supported by all devices */
100	for (i = 0;
101	uclass_get_device_by_seq(UCLASS_PCI, i, &bus) == 0 &&
102	res == 0;
103	i++)
104	res = pci_mps_find_safe(bus, &min_mps, &n);
105
106	/* If no devices were found, do not reconfigure */
107	if (n == 0)
108	return res;
109	mps = min_mps;
110	}
111
112	/* This message is checked by the sandbox test */
113	printf("Setting MPS of all devices to %uB\n", 128U << mps);
114	for (i = 0;
115	uclass_get_device_by_seq(UCLASS_PCI, i, &bus) == 0 && res == 0;
116	i++)
117	res = pci_mps_set_bus(bus, mps);
118
119	return res;
120	}
121
122	/*
123	* PCI MPS tuning commands
124	*
125	* Syntax:
126	* pci_mps safe
127	* pci_mps peer2peer
128	*/
129	static int do_pci_mps(struct cmd_tbl cmdtp, int flag, int argc, char const argv[])
130	{
131	char cmd = 'u';
132	int ret = 0;
133
134	if (argc > 1)
135	cmd = argv[1][0];
136
137	switch (cmd) {
138	case 's': /* safe */
139	ret = pci_mps_set(PCI_MPS_SAFE);
140	break;
141	case 'p': /* peer2peer/hotplug */
142	ret = pci_mps_set(PCI_MPS_PEER2PEER);
143	break;
144	default: /* usage, help */
145	goto usage;
146	}
147
148	return ret;
149	usage:
150	return CMD_RET_USAGE;
151	}
152
153	/***************************************************/
154
3616218b	155	U_BOOT_LONGHELP(pci_mps,
59b1c9be SC	156	"safe\n"
	157	" - Set PCI Express MPS of all devices to safe values\n"
	158	"pci_mps peer2peer\n"
3616218b	159	" - Set PCI Express MPS of all devices to support hotplug and peer-to-peer DMA\n");
59b1c9be SC	160
	161	U_BOOT_CMD(pci_mps, 2, 0, do_pci_mps,
	162	"configure PCI Express MPS", pci_mps_help_text);