path: root/drivers/memory/tegra/tegra186.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2017-2025 NVIDIA CORPORATION.  All rights reserved.
 */

#include <linux/io.h>
#include <linux/iommu.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>

#include <soc/tegra/mc.h>

#if defined(CONFIG_ARCH_TEGRA_186_SOC)
#include <dt-bindings/memory/tegra186-mc.h>
#endif

#include "mc.h"

#define MC_SID_STREAMID_OVERRIDE_MASK GENMASK(7, 0)
#define MC_SID_STREAMID_SECURITY_WRITE_ACCESS_DISABLED BIT(16)
#define MC_SID_STREAMID_SECURITY_OVERRIDE BIT(8)

static int tegra186_mc_probe(struct tegra_mc *mc)
{
	struct platform_device *pdev = to_platform_device(mc->dev);
	struct resource *res;
	unsigned int i;
	char name[8];
	int err;

	/*
	 * From Tegra264, the SID region is not present in MC node and BROADCAST is first.
	 * The common function 'tegra_mc_probe()' already maps first region entry from DT.
	 * Check if the SID region is present in DT then map BROADCAST. Otherwise, consider
	 * the first entry mapped in mc probe as the BROADCAST region. This is done to avoid
	 * mapping the region twice when SID is not present and keep backward compatibility.
	 */
	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "sid");
	if (res)
		mc->bcast_ch_regs = devm_platform_ioremap_resource_byname(pdev, "broadcast");
	else
		mc->bcast_ch_regs = mc->regs;

	if (IS_ERR(mc->bcast_ch_regs)) {
		if (PTR_ERR(mc->bcast_ch_regs) == -EINVAL) {
			dev_warn(&pdev->dev,
				 "Broadcast channel is missing, please update your device-tree\n");
			mc->bcast_ch_regs = NULL;
			goto populate;
		}

		return PTR_ERR(mc->bcast_ch_regs);
	}

	mc->ch_regs = devm_kcalloc(mc->dev, mc->soc->num_channels, sizeof(*mc->ch_regs),
				   GFP_KERNEL);
	if (!mc->ch_regs)
		return -ENOMEM;

	for (i = 0; i < mc->soc->num_channels; i++) {
		snprintf(name, sizeof(name), "ch%u", i);

		mc->ch_regs[i] = devm_platform_ioremap_resource_byname(pdev, name);
		if (IS_ERR(mc->ch_regs[i]))
			return PTR_ERR(mc->ch_regs[i]);
	}

populate:
	err = of_platform_populate(mc->dev->of_node, NULL, NULL, mc->dev);
	if (err < 0)
		return err;

	return 0;
}

static void tegra186_mc_remove(struct tegra_mc *mc)
{
	of_platform_depopulate(mc->dev);
}

#if IS_ENABLED(CONFIG_IOMMU_API)
static void tegra186_mc_client_sid_override(struct tegra_mc *mc,
					    const struct tegra_mc_client *client,
					    unsigned int sid)
{
	u32 value, old;

	if (client->regs.sid.security == 0 && client->regs.sid.override == 0)
		return;

	value = readl(mc->regs + client->regs.sid.security);
	if ((value & MC_SID_STREAMID_SECURITY_OVERRIDE) == 0) {
		/*
		 * If the secure firmware has locked this down the override
		 * for this memory client, there's nothing we can do here.
		 */
		if (value & MC_SID_STREAMID_SECURITY_WRITE_ACCESS_DISABLED)
			return;

		/*
		 * Otherwise, try to set the override itself. Typically the
		 * secure firmware will never have set this configuration.
		 * Instead, it will either have disabled write access to
		 * this field, or it will already have set an explicit
		 * override itself.
		 */
		WARN_ON((value & MC_SID_STREAMID_SECURITY_OVERRIDE) == 0);

		value |= MC_SID_STREAMID_SECURITY_OVERRIDE;
		writel(value, mc->regs + client->regs.sid.security);
	}

	value = readl(mc->regs + client->regs.sid.override);
	old = value & MC_SID_STREAMID_OVERRIDE_MASK;

	if (old != sid) {
		dev_dbg(mc->dev, "overriding SID %x for %s with %x\n", old,
			client->name, sid);
		writel(sid, mc->regs + client->regs.sid.override);
	}
}
#endif

static int tegra186_mc_probe_device(struct tegra_mc *mc, struct device *dev)
{
#if IS_ENABLED(CONFIG_IOMMU_API)
	struct of_phandle_args args;
	unsigned int i, index = 0;
	u32 sid;

	if (!tegra_dev_iommu_get_stream_id(dev, &sid))
		return 0;

	while (!of_parse_phandle_with_args(dev->of_node, "interconnects", "#interconnect-cells",
					   index, &args)) {
		if (args.np == mc->dev->of_node && args.args_count != 0) {
			for (i = 0; i < mc->soc->num_clients; i++) {
				const struct tegra_mc_client *client = &mc->soc->clients[i];

				if (client->id == args.args[0])
					tegra186_mc_client_sid_override(
						mc, client,
						sid