[kvm-unit-tests PATCH 02/11] arm/pci: PCI bus scanning

[Alexander Gordeev <agordeev@xxxxxxxxxx>]

Scan bus 0 and function 0 only for now

Cc: Andrew Jones <drjones@xxxxxxxxxx>
Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxx>
---
 arm/pci-test.c         |  4 +++
 lib/pci-host-generic.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/pci-host-generic.h |  1 +
 lib/pci.h              |  1 +
 4 files changed, 73 insertions(+)

diff --git a/arm/pci-test.c b/arm/pci-test.c
index 8629c89..1539d3e 100644
--- a/arm/pci-test.c
+++ b/arm/pci-test.c
@@ -11,6 +11,7 @@
 int main(void)
 {
 	struct pci *pci;
+	int ret;
 
 	pci = pci_dt_probe();
 
@@ -18,6 +19,9 @@ int main(void)
 	if (!pci)
 		goto done;
 
+	ret = pci_bus_scan(pci);
+	report("PCI bus scanning detected %d devices", true, ret);
+
 	pci_shutdown(pci);
 
 done:
diff --git a/lib/pci-host-generic.c b/lib/pci-host-generic.c
index 62b5662..e479989 100644
--- a/lib/pci-host-generic.c
+++ b/lib/pci-host-generic.c
@@ -14,6 +14,49 @@
 #include "pci-host-generic.h"
 #include <linux/pci_regs.h>
 
+#define for_each_pci_dev(pci, dev, conf)		\
+	for (dev = find_next_dev(pci, -1, &conf);	\
+	     dev >= 0;					\
+	     dev = find_next_dev(pci, dev, &conf))
+
+static u8 pci_config_readb(const void *conf, int off)
+{
+	return readb(conf + off);
+}
+
+static u32 pci_config_readl(const void *conf, int off)
+{
+	return readl(conf + off);
+}
+
+static void pci_config_writel(u32 val, void *conf, int off)
+{
+	writel(val, conf + off);
+}
+
+static void* dev_conf(struct pci *pci, int dev)
+{
+	struct pci_host_bridge *host = pci->sysdata;
+	return (void*)host->cpu_range.start + (dev * 8) * PCI_ECAM_CONFIG_SIZE;
+}
+
+/* We scan bus 0 only for now */
+static int find_next_dev(struct pci *pci, int dev, void **pconf)
+{
+	struct pci_host_bridge *host = pci->sysdata;
+	int limit = MIN(32u, host->cpu_range.size / PCI_ECAM_CONFIG_SIZE);
+
+	for (dev++; dev < limit; dev++) {
+		void *conf = dev_conf(pci, dev);
+		if (pci_config_readl(conf, PCI_VENDOR_ID) != ((u32)~0)) {
+			*pconf = conf;
+			return dev;
+		}
+	}
+
+	return -1;
+}
+
 static void pci_host_addr_space_init(struct pci_addr_space as[], int nr_as,
 				     u32 cells[], int nr_range_cells)
 {
@@ -133,6 +176,24 @@ static struct pci_host_bridge *pci_host_bridge_probe(void)
 	return host;
 }
 
+int pci_bus_scan(struct pci *pci)
+{
+	void *conf;
+	int dev;
+	int nr_dev = 0;
+
+	for_each_pci_dev(pci, dev, conf) {
+		/* We are only interested in normal PCI devices */
+		if (pci_config_readb(conf, PCI_HEADER_TYPE) !=
+					   PCI_HEADER_TYPE_NORMAL)
+			continue;
+		pci_config_writel(PCI_COMMAND_SERR, conf, PCI_COMMAND);
+		nr_dev++;
+	}
+
+	return nr_dev;
+}
+
 struct pci *pci_dt_probe(void)
 {
 	struct pci_host_bridge *host;
@@ -150,6 +211,12 @@ struct pci *pci_dt_probe(void)
 
 void pci_shutdown(struct pci *pci)
 {
+	void *conf;
+	int dev;
+
+	for_each_pci_dev(pci, dev, conf)
+		pci_config_writel(PCI_COMMAND_INTX_DISABLE, conf, PCI_COMMAND);
+
 	free(pci->sysdata);
 	free(pci);
 }
diff --git a/lib/pci-host-generic.h b/lib/pci-host-generic.h
index 097ac2d..c14d32d 100644
--- a/lib/pci-host-generic.h
+++ b/lib/pci-host-generic.h
@@ -22,5 +22,6 @@ struct pci_host_bridge {
 };
 
 #define PCI_ECAM_BUS_SIZE		(1 << 20)
+#define PCI_ECAM_CONFIG_SIZE		(1 << 12)
 
 #endif
diff --git a/lib/pci.h b/lib/pci.h
index 22b8e31..bc4f2d2 100644
--- a/lib/pci.h
+++ b/lib/pci.h
@@ -8,6 +8,7 @@ struct pci {
 };
 
 extern struct pci *pci_dt_probe(void);
+extern int pci_bus_scan(struct pci *pci);
 extern void pci_shutdown(struct pci *pci);
 
 #endif
-- 
1.8.3.1

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