[PATCH v2 08/27] ocxl: Save the device serial number in ocxl_fn

From: "Alastair D'Silva" <alastair@au1.ibm.com>
To: alastair@d-silva.org
Cc: "Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
	"Paul Mackerras" <paulus@samba.org>,
	"Michael Ellerman" <mpe@ellerman.id.au>,
	"Frederic Barrat" <fbarrat@linux.ibm.com>,
	"Andrew Donnellan" <ajd@linux.ibm.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Vishal Verma" <vishal.l.verma@intel.com>,
	"Dave Jiang" <dave.jiang@intel.com>,
	"Keith Busch" <keith.busch@intel.com>,
	"Ira Weiny" <ira.weiny@intel.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Mauro Carvalho Chehab" <mchehab+samsung@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	"Rob Herring" <robh@kernel.org>,
	"Anton Blanchard" <anton@ozlabs.org>,
	"Krzysztof Kozlowski" <krzk@kernel.org>,
	"Mahesh Salgaonkar" <mahesh@linux.vnet.ibm.com>,
	"Madhavan Srinivasan" <maddy@linux.vnet.ibm.com>,
	"Cédric Le Goater" <clg@kaod.org>,
	"Anju T Sudhakar" <anju@linux.vnet.ibm.com>,
	"Hari Bathini" <hbathini@linux.ibm.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Greg Kurz" <groug@kaod.org>,
	"Nicholas Piggin" <npiggin@gmail.com>,
	"Masahiro Yamada" <yamada.masahiro@socionext.com>,
	"Alexey Kardashevskiy" <aik@ozlabs.ru>,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-nvdimm@lists.01.org, linux-mm@kvack.org
Subject: [PATCH v2 08/27] ocxl: Save the device serial number in ocxl_fn
Date: Tue,  3 Dec 2019 14:46:36 +1100	[thread overview]
Message-ID: <20191203034655.51561-9-alastair@au1.ibm.com> (raw)
In-Reply-To: <20191203034655.51561-1-alastair@au1.ibm.com>

From: Alastair D'Silva <alastair@d-silva.org>

This patch retrieves the serial number of the card and makes it available
to consumers of the ocxl driver via the ocxl_fn struct.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
Acked-by: Andrew Donnellan <ajd@linux.ibm.com>
---
 drivers/misc/ocxl/config.c | 46 ++++++++++++++++++++++++++++++++++++++
 include/misc/ocxl.h        |  1 +
 2 files changed, 47 insertions(+)

diff --git a/drivers/misc/ocxl/config.c b/drivers/misc/ocxl/config.c
index fb0c3b6f8312..a9203c309365 100644
--- a/drivers/misc/ocxl/config.c
+++ b/drivers/misc/ocxl/config.c
@@ -71,6 +71,51 @@ static int find_dvsec_afu_ctrl(struct pci_dev *dev, u8 afu_idx)
 	return 0;
 }
 
+/**
+ * Find a related PCI device (function 0)
+ * @device: PCI device to match
+ *
+ * Returns a pointer to the related device, or null if not found
+ */
+static struct pci_dev *get_function_0(struct pci_dev *dev)
+{
+	unsigned int devfn = PCI_DEVFN(PCI_SLOT(dev->devfn), 0); // Look for function 0
+
+	return pci_get_domain_bus_and_slot(pci_domain_nr(dev->bus),
+					dev->bus->number, devfn);
+}
+
+static void read_serial(struct pci_dev *dev, struct ocxl_fn_config *fn)
+{
+	u32 low, high;
+	int pos;
+
+	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DSN);
+	if (pos) {
+		pci_read_config_dword(dev, pos + 0x04, &low);
+		pci_read_config_dword(dev, pos + 0x08, &high);
+
+		fn->serial = low | ((u64)high) << 32;
+
+		return;
+	}
+
+	if (PCI_FUNC(dev->devfn) != 0) {
+		struct pci_dev *related = get_function_0(dev);
+
+		if (!related) {
+			fn->serial = 0;
+			return;
+		}
+
+		read_serial(related, fn);
+		pci_dev_put(related);
+		return;
+	}
+
+	fn->serial = 0;
+}
+
 static void read_pasid(struct pci_dev *dev, struct ocxl_fn_config *fn)
 {
 	u16 val;
@@ -208,6 +253,7 @@ int ocxl_config_read_function(struct pci_dev *dev, struct ocxl_fn_config *fn)
 	int rc;
 
 	read_pasid(dev, fn);
+	read_serial(dev, fn);
 
 	rc = read_dvsec_tl(dev, fn);
 	if (rc) {
diff --git a/include/misc/ocxl.h b/include/misc/ocxl.h
index 6f7c02f0d5e3..9843051c3c5b 100644
--- a/include/misc/ocxl.h
+++ b/include/misc/ocxl.h
@@ -46,6 +46,7 @@ struct ocxl_fn_config {
 	int dvsec_afu_info_pos; /* offset of the AFU information DVSEC */
 	s8 max_pasid_log;
 	s8 max_afu_index;
+	u64 serial;
 };
 
 enum ocxl_endian {
-- 
2.23.0

