s390/pci: CLP interface

CLP instructions are used to query the firmware about detected PCI
functions, the attributes of those functions and to enable or disable
a PCI function. The CLP interface is the equivalent to a PCI bus scan.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 346 insertions, 1 deletions

diff --git a/arch/s390/pci/Makefile b/arch/s390/pci/Makefile
index 78a1344..1afd68c 100644
--- a/arch/s390/pci/Makefile
+++ b/arch/s390/pci/Makefile
@@ -2,4 +2,4 @@
 # Makefile for the s390 PCI subsystem.
 #
 
-obj-$(CONFIG_PCI)	+= pci.o
+obj-$(CONFIG_PCI)	+= pci.o pci_clp.o
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 0b80ac7..70f6c56 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -29,6 +29,7 @@
 
 #include <asm/facility.h>
 #include <asm/pci_insn.h>
+#include <asm/pci_clp.h>
 
 #define DEBUG				/* enable pr_debug */
 
@@ -436,6 +437,20 @@ static void zpci_free_domain(struct zpci_dev *zdev)
 	spin_unlock(&zpci_domain_lock);
 }
 
+int zpci_enable_device(struct zpci_dev *zdev)
+{
+	int rc;
+
+	rc = clp_enable_fh(zdev, ZPCI_NR_DMA_SPACES);
+	if (rc)
+		goto out;
+	pr_info("Enabled fh: 0x%x fid: 0x%x\n", zdev->fh, zdev->fid);
+	return 0;
+out:
+	return rc;
+}
+EXPORT_SYMBOL_GPL(zpci_enable_device);
+
 int zpci_create_device(struct zpci_dev *zdev)
 {
 	int rc;
@@ -455,8 +470,15 @@ int zpci_create_device(struct zpci_dev *zdev)
 	if (zdev->state == ZPCI_FN_STATE_STANDBY)
 		return 0;
 
+	rc = zpci_enable_device(zdev);
+	if (rc)
+		goto out_start;
 	return 0;
 
+out_start:
+	mutex_lock(&zpci_list_lock);
+	list_del(&zdev->entry);
+	mutex_unlock(&zpci_list_lock);
 out_bus:
 	zpci_free_domain(zdev);
 out:
@@ -489,6 +511,7 @@ int zpci_scan_device(struct zpci_dev *zdev)
 	return 0;
 
 out:
+	clp_disable_fh(zdev);
 	return -EIO;
 }
 EXPORT_SYMBOL_GPL(zpci_scan_device);
@@ -547,9 +570,14 @@ static int __init pci_base_init(void)
 	if (rc)
 		goto out_mem;
 
+	rc = clp_find_pci_devices();
+	if (rc)
+		goto out_find;
+
 	zpci_scan_devices();
 	return 0;
 
+out_find:
 	zpci_mem_exit();
 out_mem:
 	return rc;
diff --git a/arch/s390/pci/pci_clp.c b/arch/s390/pci/pci_clp.c
new file mode 100644
index 0000000..291da1a
--- /dev/null
+++ b/arch/s390/pci/pci_clp.c
@@ -0,0 +1,317 @@
+/*
+ * Copyright IBM Corp. 2012
+ *
+ * Author(s):
+ *   Jan Glauber <jang@linux.vnet.ibm.com>
+ */
+
+#define COMPONENT "zPCI"
+#define pr_fmt(fmt) COMPONENT ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/pci.h>
+#include <asm/pci_clp.h>
+
+/*
+ * Call Logical Processor
+ * Retry logic is handled by the caller.
+ */
+static inline u8 clp_instr(void *req)
+{
+	u64 ilpm;
+	u8 cc;
+
+	asm volatile (
+		"	.insn	rrf,0xb9a00000,%[ilpm],%[req],0x0,0x2\n"
+		"	ipm	%[cc]\n"
+		"	srl	%[cc],28\n"
+		: [cc] "=d" (cc), [ilpm] "=d" (ilpm)
+		: [req] "a" (req)
+		: "cc", "memory");
+	return cc;
+}
+
+static void *clp_alloc_block(void)
+{
+	struct page *page = alloc_pages(GFP_KERNEL, get_order(CLP_BLK_SIZE));
+	return (page) ? page_address(page) : NULL;
+}
+
+static void clp_free_block(void *ptr)
+{
+	free_pages((unsigned long) ptr, get_order(CLP_BLK_SIZE));
+}
+
+static void clp_store_query_pci_fngrp(struct zpci_dev *zdev,
+				      struct clp_rsp_query_pci_grp *response)
+{
+	switch (response->version) {
+	case 1:
+		zdev->max_bus_speed = PCIE_SPEED_5_0GT;
+		break;
+	default:
+		zdev->max_bus_speed = PCI_SPEED_UNKNOWN;
+		break;
+	}
+}
+
+static int clp_query_pci_fngrp(struct zpci_dev *zdev, u8 pfgid)
+{
+	struct clp_req_rsp_query_pci_grp *rrb;
+	int rc;
+
+	rrb = clp_alloc_block();
+	if (!rrb)
+		return -ENOMEM;
+
+	memset(rrb, 0, sizeof(*rrb));
+	rrb->request.hdr.len = sizeof(rrb->request);
+	rrb->request.hdr.cmd = CLP_QUERY_PCI_FNGRP;
+	rrb->response.hdr.len = sizeof(rrb->response);
+	rrb->request.pfgid = pfgid;
+
+	rc = clp_instr(rrb);
+	if (!rc && rrb->response.hdr.rsp == CLP_RC_OK)
+		clp_store_query_pci_fngrp(zdev, &rrb->response);
+	else {
+		pr_err("Query PCI FNGRP failed with response: %x  cc: %d\n",
+			rrb->response.hdr.rsp, rc);
+		rc = -EIO;
+	}
+	clp_free_block(rrb);
+	return rc;
+}
+
+static int clp_store_query_pci_fn(struct zpci_dev *zdev,
+				  struct clp_rsp_query_pci *response)
+{
+	int i;
+
+	for (i = 0; i < PCI_BAR_COUNT; i++) {
+		zdev->bars[i].val = le32_to_cpu(response->bar[i]);
+		zdev->bars[i].size = response->bar_size[i];
+	}
+	zdev->pchid = response->pchid;
+	zdev->pfgid = response->pfgid;
+	return 0;
+}
+
+static int clp_query_pci_fn(struct zpci_dev *zdev, u32 fh)
+{
+	struct clp_req_rsp_query_pci *rrb;
+	int rc;
+
+	rrb = clp_alloc_block();
+	if (!rrb)
+		return -ENOMEM;
+
+	memset(rrb, 0, sizeof(*rrb));
+	rrb->request.hdr.len = sizeof(rrb->request);
+	rrb->request.hdr.cmd = CLP_QUERY_PCI_FN;
+	rrb->response.hdr.len = sizeof(rrb->response);
+	rrb->request.fh = fh;
+
+	rc = clp_instr(rrb);
+	if (!rc && rrb->response.hdr.rsp == CLP_RC_OK) {
+		rc = clp_store_query_pci_fn(zdev, &rrb->response);
+		if (rc)
+			goto out;
+		if (rrb->response.pfgid)
+			rc = clp_query_pci_fngrp(zdev, rrb->response.pfgid);
+	} else {
+		pr_err("Query PCI failed with response: %x  cc: %d\n",
+			 rrb->response.hdr.rsp, rc);
+		rc = -EIO;
+	}
+out:
+	clp_free_block(rrb);
+	return rc;
+}
+
+int clp_add_pci_device(u32 fid, u32 fh, int configured)
+{
+	struct zpci_dev *zdev;
+	int rc;
+
+	zdev = zpci_alloc_device();
+	if (IS_ERR(zdev))
+		return PTR_ERR(zdev);
+
+	zdev->fh = fh;
+	zdev->fid = fid;
+
+	/* Query function properties and update zdev */
+	rc = clp_query_pci_fn(zdev, fh);
+	if (rc)
+		goto error;
+
+	if (configured)
+		zdev->state = ZPCI_FN_STATE_CONFIGURED;
+	else
+		zdev->state = ZPCI_FN_STATE_STANDBY;
+
+	rc = zpci_create_device(zdev);
+	if (rc)
+		goto error;
+	return 0;
+
+error:
+	zpci_free_device(zdev);
+	return rc;
+}
+
+/*
+ * Enable/Disable a given PCI function defined by its function handle.
+ */
+static int clp_set_pci_fn(u32 *fh, u8 nr_dma_as, u8 command)
+{
+	struct clp_req_rsp_set_pci *rrb;
+	int rc, retries = 1000;
+
+	rrb = clp_alloc_block();
+	if (!rrb)
+		return -ENOMEM;
+
+	do {
+		memset(rrb, 0, sizeof(*rrb));
+		rrb->request.hdr.len = sizeof(rrb->request);
+		rrb->request.hdr.cmd = CLP_SET_PCI_FN;
+		rrb->response.hdr.len = sizeof(rrb->response);
+		rrb->request.fh = *fh;
+		rrb->request.oc = command;
+		rrb->request.ndas = nr_dma_as;
+
+		rc = clp_instr(rrb);
+		if (rrb->response.hdr.rsp == CLP_RC_SETPCIFN_BUSY) {
+			retries--;
+			if (retries < 0)
+				break;
+			msleep(1);
+		}
+	} while (rrb->response.hdr.rsp == CLP_RC_SETPCIFN_BUSY);
+
+	if (!rc && rrb->response.hdr.rsp == CLP_RC_OK)
+		*fh = rrb->response.fh;
+	else {
+		pr_err("Set PCI FN failed with response: %x  cc: %d\n",
+			rrb->response.hdr.rsp, rc);
+		rc = -EIO;
+	}
+	clp_free_block(rrb);
+	return rc;
+}
+
+int clp_enable_fh(struct zpci_dev *zdev, u8 nr_dma_as)
+{
+	u32 fh = zdev->fh;
+	int rc;
+
+	rc = clp_set_pci_fn(&fh, nr_dma_as, CLP_SET_ENABLE_PCI_FN);
+	if (!rc)
+		/* Success -> store enabled handle in zdev */
+		zdev->fh = fh;
+	return rc;
+}
+
+int clp_disable_fh(struct zpci_dev *zdev)
+{
+	u32 fh = zdev->fh;
+	int rc;
+
+	if (!zdev_enabled(zdev))
+		return 0;
+
+	dev_info(&zdev->pdev->dev, "disabling fn handle: 0x%x\n", fh);
+	rc = clp_set_pci_fn(&fh, 0, CLP_SET_DISABLE_PCI_FN);
+	if (!rc)
+		/* Success -> store disabled handle in zdev */
+		zdev->fh = fh;
+	else
+		dev_err(&zdev->pdev->dev,
+			"Failed to disable fn handle: 0x%x\n", fh);
+	return rc;
+}
+
+static void clp_check_pcifn_entry(struct clp_fh_list_entry *entry)
+{
+	int present, rc;
+
+	if (!entry->vendor_id)
+		return;
+
+	/* TODO: be a little bit more scalable */
+	present = zpci_fid_present(entry->fid);
+
+	if (present)
+		pr_debug("%s: device %x already present\n", __func__, entry->fid);
+
+	/* skip already used functions */
+	if (present && entry->config_state)
+		return;
+
+	/* aev 306: function moved to stand-by state */
+	if (present && !entry->config_state) {
+		/*
+		 * The handle is already disabled, that means no iota/irq freeing via
+		 * the firmware interfaces anymore. Need to free resources manually
+		 * (DMA memory, debug, sysfs)...
+		 */
+		zpci_stop_device(get_zdev_by_fid(entry->fid));
+		return;
+	}
+
+	rc = clp_add_pci_device(entry->fid, entry->fh, entry->config_state);
+	if (rc)
+		pr_err("Failed to add fid: 0x%x\n", entry->fid);
+}
+
+int clp_find_pci_devices(void)
+{
+	struct clp_req_rsp_list_pci *rrb;
+	u64 resume_token = 0;
+	int entries, i, rc;
+
+	rrb = clp_alloc_block();
+	if (!rrb)
+		return -ENOMEM;
+
+	do {
+		memset(rrb, 0, sizeof(*rrb));
+		rrb->request.hdr.len = sizeof(rrb->request);
+		rrb->request.hdr.cmd = CLP_LIST_PCI;
+		/* store as many entries as possible */
+		rrb->response.hdr.len = CLP_BLK_SIZE - LIST_PCI_HDR_LEN;
+		rrb->request.resume_token = resume_token;
+
+		/* Get PCI function handle list */
+		rc = clp_instr(rrb);
+		if (rc || rrb->response.hdr.rsp != CLP_RC_OK) {
+			pr_err("List PCI failed with response: 0x%x  cc: %d\n",
+				rrb->response.hdr.rsp, rc);
+			rc = -EIO;
+			goto out;
+		}
+
+		WARN_ON_ONCE(rrb->response.entry_size !=
+			sizeof(struct clp_fh_list_entry));
+
+		entries = (rrb->response.hdr.len - LIST_PCI_HDR_LEN) /
+			rrb->response.entry_size;
+		pr_info("Detected number of PCI functions: %u\n", entries);
+
+		/* Store the returned resume token as input for the next call */
+		resume_token = rrb->response.resume_token;
+
+		for (i = 0; i < entries; i++)
+			clp_check_pcifn_entry(&rrb->response.fh_list[i]);
+	} while (resume_token);
+
+	pr_debug("Maximum number of supported PCI functions: %u\n",
+		rrb->response.max_fn);
+out:
+	clp_free_block(rrb);
+	return rc;
+}