On 19/08/16 18:32, Thierry Reding wrote:

From: Thierry Reding <redacted>

The Inter-VM communication (IVC) is a communication protocol which is
designed for interprocessor communication (IPC) or the communication
between the hypervisor and the virtual machine with a guest OS.

Message channels are used to communicate between processors. They are
backed by DRAM or SRAM, so care must be taken to maintain coherence of
data.

The IVC library maintains memory-based descriptors for the transmission
and reception channels as well as the data coherence of the counter and
payload. Clients, such as the driver for the BPMP firmware, can use the
library to exchange messages with remote processors.

Based on work by Peter Newman [off-list ref] and Joseph Lo
[off-list ref].

Signed-off-by: Thierry Reding <redacted>
---
Changes in v3:
- use a more object oriented design

 drivers/firmware/Kconfig        |   1 +
 drivers/firmware/Makefile       |   1 +
 drivers/firmware/tegra/Kconfig  |  13 +
 drivers/firmware/tegra/Makefile |   1 +
 drivers/firmware/tegra/ivc.c    | 683 ++++++++++++++++++++++++++++++++++++++++
 include/soc/tegra/ivc.h         | 109 +++++++
 6 files changed, 808 insertions(+)
 create mode 100644 drivers/firmware/tegra/Kconfig
 create mode 100644 drivers/firmware/tegra/Makefile
 create mode 100644 drivers/firmware/tegra/ivc.c
 create mode 100644 include/soc/tegra/ivc.h

[snip]

+static int check_ivc_params(unsigned long base1, unsigned long base2,
+			    unsigned int num_frames, size_t frame_size)
+{
+	BUG_ON(offsetof(struct tegra_ivc_header, tx.count) & (TEGRA_IVC_ALIGN - 1));
+	BUG_ON(offsetof(struct tegra_ivc_header, rx.count) & (TEGRA_IVC_ALIGN - 1));
+	BUG_ON(sizeof(struct tegra_ivc_header) & (TEGRA_IVC_ALIGN - 1));
+
+	if ((uint64_t)num_frames * (uint64_t)frame_size >= 0x100000000) {
+		pr_err("num_frames * frame_size overflows\n");
+		return -EINVAL;
+	}

This generates the following sparse warning ...

drivers/firmware/tegra/ivc.c:574:60: warning: constant 0x100000000 is so
big it is long

I think we need to append a UL.

+
+	/*
+	 * The headers must at least be aligned enough for counters
+	 * to be accessed atomically.
+	 */
+	if (base1 & (TEGRA_IVC_ALIGN - 1)) {
+		pr_err("IVC channel start not aligned: %lx\n", base1);
+		return -EINVAL;
+	}
+
+	if (base2 & (TEGRA_IVC_ALIGN - 1)) {
+		pr_err("IVC channel start not aligned: %lx\n", base2);
+		return -EINVAL;
+	}
+
+	if (frame_size & (TEGRA_IVC_ALIGN - 1)) {
+		pr_err("frame size not adequately aligned: %zu\n", frame_size);
+		return -EINVAL;
+	}
+
+	if (base1 < base2) {
+		if (base1 + frame_size * num_frames > base2) {
+			pr_err("queue regions overlap: %lx + %zx, %zx\n",
+			       base1, frame_size, frame_size * num_frames);
+			return -EINVAL;
+		}
+	} else {
+		if (base2 + frame_size * num_frames > base1) {
+			pr_err("queue regions overlap: %lx + %zx, %zx\n",
+			       base2, frame_size, frame_size * num_frames);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+int tegra_ivc_init(struct tegra_ivc *ivc, struct device *peer,
+		   void __iomem *rx_virt, dma_addr_t rx_phys,
+		   void __iomem *tx_virt, dma_addr_t tx_phys,
+		   unsigned int num_frames, size_t frame_size,
+		   void (*notify)(struct tegra_ivc *ivc, void *data),
+		   void *data)
+{
+	size_t queue_size;
+	int err;
+
+	err = check_ivc_params((unsigned long)rx_virt, (unsigned long)tx_virt,
+			       num_frames, frame_size);
+	if (err < 0)
+		return err;
+
+	BUG_ON(!ivc);
+	BUG_ON(!notify);
+
+	queue_size = tegra_ivc_total_queue_size(num_frames * frame_size);
+
+	/*
+	 * All sizes that can be returned by communication functions should
+	 * fit in an int.
+	 */
+	if (frame_size > INT_MAX)
+		return -E2BIG;
+
+	ivc->rx.channel = (struct tegra_ivc_header *)rx_virt;
+	ivc->tx.channel = (struct tegra_ivc_header *)tx_virt;

And these generate the sparse warnings ...

drivers/firmware/tegra/ivc.c:642:28: warning: cast removes address space
of expression
drivers/firmware/tegra/ivc.c:643:28: warning: cast removes address space
of expression

Cheers
Jon

-- 
nvpublic