[mirror_ubuntu-bionic-kernel.git] / arch / powerpc / platforms / pseries / msi.c

/*
 * Copyright 2006 Jake Moilanen <moilanen@austin.ibm.com>, IBM Corp.
 * Copyright 2006-2007 Michael Ellerman, IBM Corp.
 *
 * 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; version 2 of the
 * License.
 *
 */

#include <linux/device.h>
#include <linux/irq.h>
#include <linux/msi.h>

#include <asm/rtas.h>
#include <asm/hw_irq.h>
#include <asm/ppc-pci.h>

static int query_token, change_token;

#define RTAS_QUERY_FN		0
#define RTAS_CHANGE_FN		1
#define RTAS_RESET_FN		2
#define RTAS_CHANGE_MSI_FN	3
#define RTAS_CHANGE_MSIX_FN	4

static struct pci_dn *get_pdn(struct pci_dev *pdev)
{
	struct device_node *dn;
	struct pci_dn *pdn;

	dn = pci_device_to_OF_node(pdev);
	if (!dn) {
		dev_dbg(&pdev->dev, "rtas_msi: No OF device node\n");
		return NULL;
	}

	pdn = PCI_DN(dn);
	if (!pdn) {
		dev_dbg(&pdev->dev, "rtas_msi: No PCI DN\n");
		return NULL;
	}

	return pdn;
}

/* RTAS Helpers */

static int rtas_change_msi(struct pci_dn *pdn, u32 func, u32 num_irqs)
{
	u32 addr, seq_num, rtas_ret[3];
	unsigned long buid;
	int rc;

	addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
	buid = pdn->phb->buid;

	seq_num = 1;
	do {
		if (func == RTAS_CHANGE_MSI_FN || func == RTAS_CHANGE_MSIX_FN)
			rc = rtas_call(change_token, 6, 4, rtas_ret, addr,
					BUID_HI(buid), BUID_LO(buid),
					func, num_irqs, seq_num);
		else
			rc = rtas_call(change_token, 6, 3, rtas_ret, addr,
					BUID_HI(buid), BUID_LO(buid),
					func, num_irqs, seq_num);

		seq_num = rtas_ret[1];
	} while (rtas_busy_delay(rc));

	/*
	 * If the RTAS call succeeded, return the number of irqs allocated.
	 * If not, make sure we return a negative error code.
	 */
	if (rc == 0)
		rc = rtas_ret[0];
	else if (rc > 0)
		rc = -rc;

	pr_debug("rtas_msi: ibm,change_msi(func=%d,num=%d), got %d rc = %d\n",
		 func, num_irqs, rtas_ret[0], rc);

	return rc;
}

static void rtas_disable_msi(struct pci_dev *pdev)
{
	struct pci_dn *pdn;

	pdn = get_pdn(pdev);
	if (!pdn)
		return;

	/*
	 * disabling MSI with the explicit interface also disables MSI-X
	 */
	if (rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, 0) != 0) {
		/* 
		 * may have failed because explicit interface is not
		 * present
		 */
		if (rtas_change_msi(pdn, RTAS_CHANGE_FN, 0) != 0) {
			pr_debug("rtas_msi: Setting MSIs to 0 failed!\n");
		}
	}
}

static int rtas_query_irq_number(struct pci_dn *pdn, int offset)
{
	u32 addr, rtas_ret[2];
	unsigned long buid;
	int rc;

	addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
	buid = pdn->phb->buid;

	do {
		rc = rtas_call(query_token, 4, 3, rtas_ret, addr,
			       BUID_HI(buid), BUID_LO(buid), offset);
	} while (rtas_busy_delay(rc));

	if (rc) {
		pr_debug("rtas_msi: error (%d) querying source number\n", rc);
		return rc;
	}

	return rtas_ret[0];
}

static void rtas_teardown_msi_irqs(struct pci_dev *pdev)
{
	struct msi_desc *entry;

	list_for_each_entry(entry, &pdev->msi_list, list) {
		if (entry->irq == NO_IRQ)
			continue;

		irq_set_msi_desc(entry->irq, NULL);
		irq_dispose_mapping(entry->irq);
	}

	rtas_disable_msi(pdev);
}

static int check_req(struct pci_dev *pdev, int nvec, char *prop_name)
{
	struct device_node *dn;
	struct pci_dn *pdn;
	const u32 *req_msi;

	pdn = get_pdn(pdev);
	if (!pdn)
		return -ENODEV;

	dn = pdn->node;

	req_msi = of_get_property(dn, prop_name, NULL);
	if (!req_msi) {
		pr_debug("rtas_msi: No %s on %s\n", prop_name, dn->full_name);
		return -ENOENT;
	}

	if (*req_msi < nvec) {
		pr_debug("rtas_msi: %s requests < %d MSIs\n", prop_name, nvec);

		if (*req_msi == 0) /* Be paranoid */
			return -ENOSPC;

		return *req_msi;
	}

	return 0;
}

static int check_req_msi(struct pci_dev *pdev, int nvec)
{
	return check_req(pdev, nvec, "ibm,req#msi");
}

static int check_req_msix(struct pci_dev *pdev, int nvec)
{
	return check_req(pdev, nvec, "ibm,req#msi-x");
}

/* Quota calculation */

static struct device_node *find_pe_total_msi(struct pci_dev *dev, int *total)
{
	struct device_node *dn;
	const u32 *p;

	dn = of_node_get(pci_device_to_OF_node(dev));
	while (dn) {
		p = of_get_property(dn, "ibm,pe-total-#msi", NULL);
		if (p) {
			pr_debug("rtas_msi: found prop on dn %s\n",
				dn->full_name);
			*total = *p;
			return dn;
		}

		dn = of_get_next_parent(dn);
	}

	return NULL;
}

static struct device_node *find_pe_dn(struct pci_dev *dev, int *total)
{
	struct device_node *dn;
	struct eeh_dev *edev;

	/* Found our PE and assume 8 at that point. */

	dn = pci_device_to_OF_node(dev);
	if (!dn)
		return NULL;

	/* Get the top level device in the PE */
	edev = of_node_to_eeh_dev(dn);
	if (edev->pe)
		edev = list_first_entry(&edev->pe->edevs, struct eeh_dev, list);
	dn = eeh_dev_to_of_node(edev);
	if (!dn)
		return NULL;

	/* We actually want the parent */
	dn = of_get_parent(dn);
	if (!dn)
		return NULL;

	/* Hardcode of 8 for old firmwares */
	*total = 8;
	pr_debug("rtas_msi: using PE dn %s\n", dn->full_name);

	return dn;
}

struct msi_counts {
	struct device_node *requestor;
	int num_devices;
	int request;
	int quota;
	int spare;
	int over_quota;
};

static void *count_non_bridge_devices(struct device_node *dn, void *data)
{
	struct msi_counts *counts = data;
	const u32 *p;
	u32 class;

	pr_debug("rtas_msi: counting %s\n", dn->full_name);

	p = of_get_property(dn, "class-code", NULL);
	class = p ? *p : 0;

	if ((class >> 8) != PCI_CLASS_BRIDGE_PCI)
		counts->num_devices++;

	return NULL;
}

static void *count_spare_msis(struct device_node *dn, void *data)
{
	struct msi_counts *counts = data;
	const u32 *p;
	int req;

	if (dn == counts->requestor)
		req = counts->request;
	else {
		/* We don't know if a driver will try to use MSI or MSI-X,
		 * so we just have to punt and use the larger of the two. */
		req = 0;
		p = of_get_property(dn, "ibm,req#msi", NULL);
		if (p)
			req = *p;

		p = of_get_property(dn, "ibm,req#msi-x", NULL);
		if (p)
			req = max(req, (int)*p);
	}

	if (req < counts->quota)
		counts->spare += counts->quota - req;
	else if (req > counts->quota)
		counts->over_quota++;

	return NULL;
}

static int msi_quota_for_device(struct pci_dev *dev, int request)
{
	struct device_node *pe_dn;
	struct msi_counts counts;
	int total;

	pr_debug("rtas_msi: calc quota for %s, request %d\n", pci_name(dev),
		  request);

	pe_dn = find_pe_total_msi(dev, &total);
	if (!pe_dn)
		pe_dn = find_pe_dn(dev, &total);

	if (!pe_dn) {
		pr_err("rtas_msi: couldn't find PE for %s\n", pci_name(dev));
		goto out;
	}

	pr_debug("rtas_msi: found PE %s\n", pe_dn->full_name);

	memset(&counts, 0, sizeof(struct msi_counts));

	/* Work out how many devices we have below this PE */
	traverse_pci_devices(pe_dn, count_non_bridge_devices, &counts);

	if (counts.num_devices == 0) {
		pr_err("rtas_msi: found 0 devices under PE for %s\n",
			pci_name(dev));
		goto out;
	}

	counts.quota = total / counts.num_devices;
	if (request <= counts.quota)
		goto out;

	/* else, we have some more calculating to do */
	counts.requestor = pci_device_to_OF_node(dev);
	counts.request = request;
	traverse_pci_devices(pe_dn, count_spare_msis, &counts);

	/* If the quota isn't an integer multiple of the total, we can
	 * use the remainder as spare MSIs for anyone that wants them. */
	counts.spare += total % counts.num_devices;

	/* Divide any spare by the number of over-quota requestors */
	if (counts.over_quota)
		counts.quota += counts.spare / counts.over_quota;

	/* And finally clamp the request to the possibly adjusted quota */
	request = min(counts.quota, request);

	pr_debug("rtas_msi: request clamped to quota %d\n", request);
out:
	of_node_put(pe_dn);

	return request;
}

static int rtas_msi_check_device(struct pci_dev *pdev, int nvec, int type)
{
	int quota, rc;

	if (type == PCI_CAP_ID_MSIX)
		rc = check_req_msix(pdev, nvec);
	else
		rc = check_req_msi(pdev, nvec);

	if (rc)
		return rc;

	quota = msi_quota_for_device(pdev, nvec);

	if (quota && quota < nvec)
		return quota;

	return 0;
}

static int check_msix_entries(struct pci_dev *pdev)
{
	struct msi_desc *entry;
	int expected;

	/* There's no way for us to express to firmware that we want
	 * a discontiguous, or non-zero based, range of MSI-X entries.
	 * So we must reject such requests. */

	expected = 0;
	list_for_each_entry(entry, &pdev->msi_list, list) {
		if (entry->msi_attrib.entry_nr != expected) {
			pr_debug("rtas_msi: bad MSI-X entries.\n");
			return -EINVAL;
		}
		expected++;
	}

	return 0;
}

static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec_in, int type)
{
	struct pci_dn *pdn;
	int hwirq, virq, i, rc;
	struct msi_desc *entry;
	struct msi_msg msg;
	int nvec = nvec_in;

	pdn = get_pdn(pdev);
	if (!pdn)
		return -ENODEV;

	if (type == PCI_CAP_ID_MSIX && check_msix_entries(pdev))
		return -EINVAL;

	/*
	 * Firmware currently refuse any non power of two allocation
	 * so we round up if the quota will allow it.
	 */
	if (type == PCI_CAP_ID_MSIX) {
		int m = roundup_pow_of_two(nvec);
		int quota = msi_quota_for_device(pdev, m);

		if (quota >= m)
			nvec = m;
	}

	/*
	 * Try the new more explicit firmware interface, if that fails fall
	 * back to the old interface. The old interface is known to never
	 * return MSI-Xs.
	 */
again:
	if (type == PCI_CAP_ID_MSI) {
		rc = rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, nvec);

		if (rc < 0) {
			pr_debug("rtas_msi: trying the old firmware call.\n");
			rc = rtas_change_msi(pdn, RTAS_CHANGE_FN, nvec);
		}
	} else
		rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec);

	if (rc != nvec) {
		if (nvec != nvec_in) {
			nvec = nvec_in;
			goto again;
		}
		pr_debug("rtas_msi: rtas_change_msi() failed\n");
		return rc;
	}

	i = 0;
	list_for_each_entry(entry, &pdev->msi_list, list) {
		hwirq = rtas_query_irq_number(pdn, i++);
		if (hwirq < 0) {
			pr_debug("rtas_msi: error (%d) getting hwirq\n", rc);
			return hwirq;
		}

		virq = irq_create_mapping(NULL, hwirq);

		if (virq == NO_IRQ) {
			pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq);
			return -ENOSPC;
		}

		dev_dbg(&pdev->dev, "rtas_msi: allocated virq %d\n", virq);
		irq_set_msi_desc(virq, entry);

		/* Read config space back so we can restore after reset */
		read_msi_msg(virq, &msg);
		entry->msg = msg;
	}

	return 0;
}

static void rtas_msi_pci_irq_fixup(struct pci_dev *pdev)
{
	/* No LSI -> leave MSIs (if any) configured */
	if (pdev->irq == NO_IRQ) {
		dev_dbg(&pdev->dev, "rtas_msi: no LSI, nothing to do.\n");
		return;
	}

	/* No MSI -> MSIs can't have been assigned by fw, leave LSI */
	if (check_req_msi(pdev, 1) && check_req_msix(pdev, 1)) {
		dev_dbg(&pdev->dev, "rtas_msi: no req#msi/x, nothing to do.\n");
		return;
	}

	dev_dbg(&pdev->dev, "rtas_msi: disabling existing MSI.\n");
	rtas_disable_msi(pdev);
}

static int rtas_msi_init(void)
{
	query_token  = rtas_token("ibm,query-interrupt-source-number");
	change_token = rtas_token("ibm,change-msi");

	if ((query_token == RTAS_UNKNOWN_SERVICE) ||
			(change_token == RTAS_UNKNOWN_SERVICE)) {
		pr_debug("rtas_msi: no RTAS tokens, no MSI support.\n");
		return -1;
	}

	pr_debug("rtas_msi: Registering RTAS MSI callbacks.\n");

	WARN_ON(ppc_md.setup_msi_irqs);
	ppc_md.setup_msi_irqs = rtas_setup_msi_irqs;
	ppc_md.teardown_msi_irqs = rtas_teardown_msi_irqs;
	ppc_md.msi_check_device = rtas_msi_check_device;

	WARN_ON(ppc_md.pci_irq_fixup);
	ppc_md.pci_irq_fixup = rtas_msi_pci_irq_fixup;

	return 0;
}
arch_initcall(rtas_msi_init);
Commit	Line	Data
85f2bf9f ME	1	/*
	2	* Copyright 2006 Jake Moilanen <moilanen@austin.ibm.com>, IBM Corp.
	3	* Copyright 2006-2007 Michael Ellerman, IBM Corp.
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License
	7	* as published by the Free Software Foundation; version 2 of the
	8	* License.
	9	*
	10	*/
	11
	12	#include <linux/device.h>
	13	#include <linux/irq.h>
	14	#include <linux/msi.h>
	15
	16	#include <asm/rtas.h>
	17	#include <asm/hw_irq.h>
	18	#include <asm/ppc-pci.h>
	19
	20	static int query_token, change_token;
	21
	22	#define RTAS_QUERY_FN 0
	23	#define RTAS_CHANGE_FN 1
	24	#define RTAS_RESET_FN 2
	25	#define RTAS_CHANGE_MSI_FN 3
	26	#define RTAS_CHANGE_MSIX_FN 4
	27
	28	static struct pci_dn get_pdn(struct pci_dev pdev)
	29	{
	30	struct device_node *dn;
	31	struct pci_dn *pdn;
	32
	33	dn = pci_device_to_OF_node(pdev);
	34	if (!dn) {
	35	dev_dbg(&pdev->dev, "rtas_msi: No OF device node\n");
	36	return NULL;
	37	}
	38
	39	pdn = PCI_DN(dn);
	40	if (!pdn) {
	41	dev_dbg(&pdev->dev, "rtas_msi: No PCI DN\n");
	42	return NULL;
	43	}
	44
	45	return pdn;
	46	}
	47
	48	/* RTAS Helpers */
	49
	50	static int rtas_change_msi(struct pci_dn *pdn, u32 func, u32 num_irqs)
	51	{
	52	u32 addr, seq_num, rtas_ret[3];
	53	unsigned long buid;
	54	int rc;
	55
	56	addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
	57	buid = pdn->phb->buid;
	58
	59	seq_num = 1;
	60	do {
	61	if (func == RTAS_CHANGE_MSI_FN \|\| func == RTAS_CHANGE_MSIX_FN)
	62	rc = rtas_call(change_token, 6, 4, rtas_ret, addr,
	63	BUID_HI(buid), BUID_LO(buid),
	64	func, num_irqs, seq_num);
65	else
66	rc = rtas_call(change_token, 6, 3, rtas_ret, addr,
67	BUID_HI(buid), BUID_LO(buid),
68	func, num_irqs, seq_num);
69
70	seq_num = rtas_ret[1];
71	} while (rtas_busy_delay(rc));
72
d385366a	73	/*
6071ed04 ME	74	* If the RTAS call succeeded, return the number of irqs allocated.
6071ed04 ME	75	* If not, make sure we return a negative error code.
d385366a	76	*/
6071ed04 ME	77	if (rc == 0)
	78	rc = rtas_ret[0];
	79	else if (rc > 0)
	80	rc = -rc;
85f2bf9f	81
d385366a ME	82	pr_debug("rtas_msi: ibm,change_msi(func=%d,num=%d), got %d rc = %d\n",
d385366a ME	83	func, num_irqs, rtas_ret[0], rc);
85f2bf9f ME	84
	85	return rc;
	86	}
	87
	88	static void rtas_disable_msi(struct pci_dev *pdev)
	89	{
	90	struct pci_dn *pdn;
	91
	92	pdn = get_pdn(pdev);
	93	if (!pdn)
	94	return;
	95
964a2996 NA	96	/*
	97	* disabling MSI with the explicit interface also disables MSI-X
	98	*/
	99	if (rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, 0) != 0) {
	100	/*
	101	* may have failed because explicit interface is not
	102	* present
	103	*/
	104	if (rtas_change_msi(pdn, RTAS_CHANGE_FN, 0) != 0) {
	105	pr_debug("rtas_msi: Setting MSIs to 0 failed!\n");
	106	}
	107	}
85f2bf9f ME	108	}
	109
	110	static int rtas_query_irq_number(struct pci_dn *pdn, int offset)
	111	{
	112	u32 addr, rtas_ret[2];
	113	unsigned long buid;
	114	int rc;
	115
	116	addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
	117	buid = pdn->phb->buid;
	118
	119	do {
	120	rc = rtas_call(query_token, 4, 3, rtas_ret, addr,
	121	BUID_HI(buid), BUID_LO(buid), offset);
	122	} while (rtas_busy_delay(rc));
	123
	124	if (rc) {
	125	pr_debug("rtas_msi: error (%d) querying source number\n", rc);
	126	return rc;
	127	}
	128
	129	return rtas_ret[0];
	130	}
	131
	132	static void rtas_teardown_msi_irqs(struct pci_dev *pdev)
	133	{
	134	struct msi_desc *entry;
	135
	136	list_for_each_entry(entry, &pdev->msi_list, list) {
	137	if (entry->irq == NO_IRQ)
	138	continue;
	139
ec775d0e	140	irq_set_msi_desc(entry->irq, NULL);
85f2bf9f ME	141	irq_dispose_mapping(entry->irq);
	142	}
	143
	144	rtas_disable_msi(pdev);
	145	}
	146
3a51c0cb	147	static int check_req(struct pci_dev pdev, int nvec, char prop_name)
85f2bf9f ME	148	{
	149	struct device_node *dn;
	150	struct pci_dn *pdn;
	151	const u32 *req_msi;
	152
	153	pdn = get_pdn(pdev);
	154	if (!pdn)
	155	return -ENODEV;
	156
	157	dn = pdn->node;
	158
3a51c0cb	159	req_msi = of_get_property(dn, prop_name, NULL);
85f2bf9f	160	if (!req_msi) {
3a51c0cb	161	pr_debug("rtas_msi: No %s on %s\n", prop_name, dn->full_name);
85f2bf9f ME	162	return -ENOENT;
	163	}
	164
	165	if (*req_msi < nvec) {
3a51c0cb	166	pr_debug("rtas_msi: %s requests < %d MSIs\n", prop_name, nvec);
d523cc37 ME	167
	168	if (req_msi == 0) / Be paranoid */
	169	return -ENOSPC;
	170
	171	return *req_msi;
85f2bf9f ME	172	}
	173
	174	return 0;
	175	}
	176
3a51c0cb ME	177	static int check_req_msi(struct pci_dev *pdev, int nvec)
	178	{
	179	return check_req(pdev, nvec, "ibm,req#msi");
	180	}
	181
	182	static int check_req_msix(struct pci_dev *pdev, int nvec)
	183	{
	184	return check_req(pdev, nvec, "ibm,req#msi-x");
	185	}
	186
448e2ca0 ME	187	/* Quota calculation */
	188
	189	static struct device_node find_pe_total_msi(struct pci_dev dev, int *total)
	190	{
	191	struct device_node *dn;
	192	const u32 *p;
	193
	194	dn = of_node_get(pci_device_to_OF_node(dev));
	195	while (dn) {
	196	p = of_get_property(dn, "ibm,pe-total-#msi", NULL);
	197	if (p) {
	198	pr_debug("rtas_msi: found prop on dn %s\n",
	199	dn->full_name);
	200	total = p;
	201	return dn;
	202	}
	203
	204	dn = of_get_next_parent(dn);
	205	}
	206
	207	return NULL;
	208	}
	209
	210	static struct device_node find_pe_dn(struct pci_dev dev, int *total)
	211	{
	212	struct device_node *dn;
66523d9f	213	struct eeh_dev *edev;
448e2ca0 ME	214
	215	/* Found our PE and assume 8 at that point. */
	216
	217	dn = pci_device_to_OF_node(dev);
	218	if (!dn)
	219	return NULL;
	220
66523d9f GS	221	/* Get the top level device in the PE */
66523d9f GS	222	edev = of_node_to_eeh_dev(dn);
bb461882 AK	223	if (edev->pe)
bb461882 AK	224	edev = list_first_entry(&edev->pe->edevs, struct eeh_dev, list);
66523d9f	225	dn = eeh_dev_to_of_node(edev);
448e2ca0 ME	226	if (!dn)
	227	return NULL;
	228
	229	/* We actually want the parent */
	230	dn = of_get_parent(dn);
	231	if (!dn)
	232	return NULL;
	233
	234	/* Hardcode of 8 for old firmwares */
	235	*total = 8;
	236	pr_debug("rtas_msi: using PE dn %s\n", dn->full_name);
	237
	238	return dn;
	239	}
	240
	241	struct msi_counts {
	242	struct device_node *requestor;
	243	int num_devices;
	244	int request;
	245	int quota;
	246	int spare;
	247	int over_quota;
	248	};
	249
	250	static void count_non_bridge_devices(struct device_node dn, void *data)
	251	{
	252	struct msi_counts *counts = data;
	253	const u32 *p;
	254	u32 class;
	255
	256	pr_debug("rtas_msi: counting %s\n", dn->full_name);
	257
	258	p = of_get_property(dn, "class-code", NULL);
	259	class = p ? *p : 0;
	260
	261	if ((class >> 8) != PCI_CLASS_BRIDGE_PCI)
	262	counts->num_devices++;
	263
	264	return NULL;
	265	}
	266
	267	static void count_spare_msis(struct device_node dn, void *data)
	268	{
	269	struct msi_counts *counts = data;
	270	const u32 *p;
	271	int req;
	272
	273	if (dn == counts->requestor)
	274	req = counts->request;
	275	else {
	276	/* We don't know if a driver will try to use MSI or MSI-X,
	277	* so we just have to punt and use the larger of the two. */
	278	req = 0;
	279	p = of_get_property(dn, "ibm,req#msi", NULL);
	280	if (p)
	281	req = *p;
	282
	283	p = of_get_property(dn, "ibm,req#msi-x", NULL);
	284	if (p)
	285	req = max(req, (int)*p);
	286	}
	287
	288	if (req < counts->quota)
	289	counts->spare += counts->quota - req;
290	else if (req > counts->quota)
291	counts->over_quota++;
292
293	return NULL;
294	}
295
296	static int msi_quota_for_device(struct pci_dev *dev, int request)
297	{
298	struct device_node *pe_dn;
299	struct msi_counts counts;
300	int total;
301
302	pr_debug("rtas_msi: calc quota for %s, request %d\n", pci_name(dev),
303	request);
304
305	pe_dn = find_pe_total_msi(dev, &total);
306	if (!pe_dn)
307	pe_dn = find_pe_dn(dev, &total);
308
309	if (!pe_dn) {
310	pr_err("rtas_msi: couldn't find PE for %s\n", pci_name(dev));
311	goto out;
312	}
313
314	pr_debug("rtas_msi: found PE %s\n", pe_dn->full_name);
315
316	memset(&counts, 0, sizeof(struct msi_counts));
317
318	/* Work out how many devices we have below this PE */
319	traverse_pci_devices(pe_dn, count_non_bridge_devices, &counts);
320
321	if (counts.num_devices == 0) {
322	pr_err("rtas_msi: found 0 devices under PE for %s\n",
323	pci_name(dev));
324	goto out;
325	}
326
327	counts.quota = total / counts.num_devices;
328	if (request <= counts.quota)
329	goto out;
330
331	/* else, we have some more calculating to do */
332	counts.requestor = pci_device_to_OF_node(dev);
333	counts.request = request;
334	traverse_pci_devices(pe_dn, count_spare_msis, &counts);
335
336	/* If the quota isn't an integer multiple of the total, we can
337	* use the remainder as spare MSIs for anyone that wants them. */
338	counts.spare += total % counts.num_devices;
339
340	/* Divide any spare by the number of over-quota requestors */
341	if (counts.over_quota)
342	counts.quota += counts.spare / counts.over_quota;
343
344	/* And finally clamp the request to the possibly adjusted quota */
345	request = min(counts.quota, request);
346
347	pr_debug("rtas_msi: request clamped to quota %d\n", request);
348	out:
349	of_node_put(pe_dn);
350
351	return request;
352	}
353
85f2bf9f ME	354	static int rtas_msi_check_device(struct pci_dev *pdev, int nvec, int type)
85f2bf9f ME	355	{
448e2ca0 ME	356	int quota, rc;
448e2ca0 ME	357
85f2bf9f	358	if (type == PCI_CAP_ID_MSIX)
448e2ca0 ME	359	rc = check_req_msix(pdev, nvec);
	360	else
	361	rc = check_req_msi(pdev, nvec);
	362
	363	if (rc)
	364	return rc;
85f2bf9f	365
448e2ca0 ME	366	quota = msi_quota_for_device(pdev, nvec);
	367
	368	if (quota && quota < nvec)
	369	return quota;
	370
	371	return 0;
85f2bf9f ME	372	}
85f2bf9f ME	373
94afa5a5 ME	374	static int check_msix_entries(struct pci_dev *pdev)
	375	{
	376	struct msi_desc *entry;
	377	int expected;
	378
	379	/* There's no way for us to express to firmware that we want
	380	* a discontiguous, or non-zero based, range of MSI-X entries.
	381	* So we must reject such requests. */
	382
	383	expected = 0;
	384	list_for_each_entry(entry, &pdev->msi_list, list) {
	385	if (entry->msi_attrib.entry_nr != expected) {
	386	pr_debug("rtas_msi: bad MSI-X entries.\n");
	387	return -EINVAL;
	388	}
	389	expected++;
	390	}
	391
	392	return 0;
	393	}
	394
752f5216	395	static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec_in, int type)
85f2bf9f ME	396	{
	397	struct pci_dn *pdn;
	398	int hwirq, virq, i, rc;
	399	struct msi_desc *entry;
1db3e890	400	struct msi_msg msg;
752f5216	401	int nvec = nvec_in;
85f2bf9f ME	402
	403	pdn = get_pdn(pdev);
	404	if (!pdn)
	405	return -ENODEV;
	406
94afa5a5 ME	407	if (type == PCI_CAP_ID_MSIX && check_msix_entries(pdev))
	408	return -EINVAL;
	409
752f5216 AB	410	/*
	411	* Firmware currently refuse any non power of two allocation
	412	* so we round up if the quota will allow it.
	413	*/
	414	if (type == PCI_CAP_ID_MSIX) {
	415	int m = roundup_pow_of_two(nvec);
	416	int quota = msi_quota_for_device(pdev, m);
	417
	418	if (quota >= m)
	419	nvec = m;
	420	}
	421
85f2bf9f ME	422	/*
	423	* Try the new more explicit firmware interface, if that fails fall
	424	* back to the old interface. The old interface is known to never
	425	* return MSI-Xs.
	426	*/
752f5216	427	again:
85f2bf9f ME	428	if (type == PCI_CAP_ID_MSI) {
	429	rc = rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, nvec);
	430
6071ed04	431	if (rc < 0) {
85f2bf9f ME	432	pr_debug("rtas_msi: trying the old firmware call.\n");
	433	rc = rtas_change_msi(pdn, RTAS_CHANGE_FN, nvec);
	434	}
	435	} else
	436	rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec);
	437
6071ed04	438	if (rc != nvec) {
752f5216 AB	439	if (nvec != nvec_in) {
	440	nvec = nvec_in;
	441	goto again;
	442	}
85f2bf9f	443	pr_debug("rtas_msi: rtas_change_msi() failed\n");
fcbe8090	444	return rc;
85f2bf9f ME	445	}
	446
	447	i = 0;
	448	list_for_each_entry(entry, &pdev->msi_list, list) {
e27ed698	449	hwirq = rtas_query_irq_number(pdn, i++);
85f2bf9f	450	if (hwirq < 0) {
85f2bf9f	451	pr_debug("rtas_msi: error (%d) getting hwirq\n", rc);
fcbe8090	452	return hwirq;
85f2bf9f ME	453	}
	454
	455	virq = irq_create_mapping(NULL, hwirq);
	456
	457	if (virq == NO_IRQ) {
	458	pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq);
fcbe8090	459	return -ENOSPC;
85f2bf9f ME	460	}
	461
	462	dev_dbg(&pdev->dev, "rtas_msi: allocated virq %d\n", virq);
ec775d0e	463	irq_set_msi_desc(virq, entry);
1db3e890 ME	464
	465	/* Read config space back so we can restore after reset */
	466	read_msi_msg(virq, &msg);
	467	entry->msg = msg;
85f2bf9f ME	468	}
	469
	470	return 0;
85f2bf9f ME	471	}
	472
	473	static void rtas_msi_pci_irq_fixup(struct pci_dev *pdev)
	474	{
	475	/* No LSI -> leave MSIs (if any) configured */
	476	if (pdev->irq == NO_IRQ) {
	477	dev_dbg(&pdev->dev, "rtas_msi: no LSI, nothing to do.\n");
	478	return;
	479	}
	480
	481	/* No MSI -> MSIs can't have been assigned by fw, leave LSI */
649781f8 ME	482	if (check_req_msi(pdev, 1) && check_req_msix(pdev, 1)) {
649781f8 ME	483	dev_dbg(&pdev->dev, "rtas_msi: no req#msi/x, nothing to do.\n");
85f2bf9f ME	484	return;
	485	}
	486
	487	dev_dbg(&pdev->dev, "rtas_msi: disabling existing MSI.\n");
	488	rtas_disable_msi(pdev);
	489	}
	490
	491	static int rtas_msi_init(void)
	492	{
	493	query_token = rtas_token("ibm,query-interrupt-source-number");
	494	change_token = rtas_token("ibm,change-msi");
	495
	496	if ((query_token == RTAS_UNKNOWN_SERVICE) \|\|
	497	(change_token == RTAS_UNKNOWN_SERVICE)) {
	498	pr_debug("rtas_msi: no RTAS tokens, no MSI support.\n");
	499	return -1;
	500	}
	501
	502	pr_debug("rtas_msi: Registering RTAS MSI callbacks.\n");
	503
	504	WARN_ON(ppc_md.setup_msi_irqs);
	505	ppc_md.setup_msi_irqs = rtas_setup_msi_irqs;
	506	ppc_md.teardown_msi_irqs = rtas_teardown_msi_irqs;
	507	ppc_md.msi_check_device = rtas_msi_check_device;
	508
	509	WARN_ON(ppc_md.pci_irq_fixup);
	510	ppc_md.pci_irq_fixup = rtas_msi_pci_irq_fixup;
	511
	512	return 0;
	513	}
	514	arch_initcall(rtas_msi_init);