[dpdk-dev] [RFC PATCH 3/5] pci/windows: split config I/O into series of fixed-size operations

[Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>]

PCI bus kernel driver mandates accessing config space in a series of
reads/writes by 4, 2, or 1 bytes. NETUIO driver checks this requirement
before performing config space I/O. Users of DPDK PCI bus driver,
however, access config space without regard for this requirement.

Make DPDK PCI bus driver split config I/O to a series of 4-, 2-,
or 1-byte reads/writes. Each of these operations is a syscall to netUIO.

Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
---
 drivers/bus/pci/windows/pci.c | 45 ++++++++++++++++++++++++-----------
 1 file changed, 31 insertions(+), 14 deletions(-)

diff --git a/drivers/bus/pci/windows/pci.c b/drivers/bus/pci/windows/pci.c
index 387ed4f02..4ffa6a610 100644
--- a/drivers/bus/pci/windows/pci.c
+++ b/drivers/bus/pci/windows/pci.c
@@ -200,6 +200,32 @@ int send_ioctl(HANDLE f, DWORD ioctl,
 	return ERROR_SUCCESS;
 }
 
+static int
+pci_config_io_sized(HANDLE device, struct dpdk_pci_config_io *io,
+	void **buf, size_t *left_size, size_t access_size)
+{
+	uint64_t out;
+
+	io->access_size = access_size;
+
+	while (*left_size >= access_size) {
+		if (io->op == PCI_IO_WRITE)
+			memcpy(&io->data, *buf, access_size);
+
+		if (send_ioctl(device, IOCTL_NETUIO_PCI_CONFIG_IO,
+				io, sizeof(*io), &out, sizeof(out)) != ERROR_SUCCESS)
+			return -1;
+
+		if (io->op == PCI_IO_READ)
+			memcpy(*buf, &out, access_size);
+
+		io->offset += access_size;
+		*buf += access_size;
+		*left_size -= access_size;
+	}
+	return 0;
+}
+
 /* Send IOCTL to driver to read/write PCI configuration space */
 static
 int pci_config_io(const struct rte_pci_device *dev, void *buf,
@@ -227,23 +253,14 @@ int pci_config_io(const struct rte_pci_device *dev, void *buf,
 	pci_io.dev_addr.dev_num = dev->addr.devid;
 	pci_io.dev_addr.func_num = dev->addr.function;
 	pci_io.offset = offset;
-	pci_io.access_size = sizeof(UINT32);
 	pci_io.op = operation;
 
-	if (operation == PCI_IO_WRITE)
-	{
-		pci_io.data.u32 = *(UINT32 UNALIGNED*)buf;
-	}
-
-	uint64_t  outputbuf = 0;
-	if (send_ioctl(f, IOCTL_NETUIO_PCI_CONFIG_IO, &pci_io, sizeof(pci_io),
-				&outputbuf, sizeof(outputbuf)) != ERROR_SUCCESS)
+	if (pci_config_io_sized(f, &pci_io, &buf, &len, sizeof(uint32_t)) < 0)
+		goto error;
+	if (pci_config_io_sized(f, &pci_io, &buf, &len, sizeof(uint16_t)) < 0)
+		goto error;
+	if (pci_config_io_sized(f, &pci_io, &buf, &len, sizeof(uint8_t)) < 0)
 		goto error;
-
-	if (operation == PCI_IO_READ)
-	{
-		memcpy(buf, &outputbuf, sizeof(UINT32));
-	}
 
 	ret = 0;
 error:
-- 
2.25.1