[Patch v3 2/2] memory: tegra: make sid and broadcast regions optional

Sumit Gupta
2024-04-12T13:06:21Z

MC SID and Broadbast channel register access is restricted for Guest VM.
In Tegra MC driver, consider both the regions as optional and skip
access to restricted registers from Guest if a region is not present
in Guest DT.

Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
---
drivers/memory/tegra/mc.c | 9 ++++++++-
drivers/memory/tegra/mc.h | 22 ++++++++++++----------
drivers/memory/tegra/tegra186.c | 25 +++++++++++++------------
3 files changed, 33 insertions(+), 23 deletions(-)

diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
index 224b488794e5..d819dab1b223 100644
--- a/drivers/memory/tegra/mc.c
+++ b/drivers/memory/tegra/mc.c
@@ -899,6 +899,7 @@ static void tegra_mc_num_channel_enabled(struct tegra_mc *mc)

static int tegra_mc_probe(struct platform_device *pdev)
{
+ struct resource *res;
struct tegra_mc *mc;
u64 mask;
int err;
@@ -923,7 +924,13 @@ static int tegra_mc_probe(struct platform_device *pdev)
/* length of MC tick in nanoseconds */
mc->tick = 30;

- mc->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (mc->soc->num_channels) {
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "sid");
+ if (res)
+ mc->regs = devm_ioremap_resource(&pdev->dev, res);
+ } else {
+ mc->regs = devm_platform_ioremap_resource(pdev, 0);
+ }
if (IS_ERR(mc->regs))
return PTR_ERR(mc->regs);

diff --git a/drivers/memory/tegra/mc.h b/drivers/memory/tegra/mc.h
index c3f6655bec60..7e7bd3e09cdc 100644
--- a/drivers/memory/tegra/mc.h
+++ b/drivers/memory/tegra/mc.h
@@ -112,25 +112,27 @@ icc_provider_to_tegra_mc(struct icc_provider *provider)
static inline u32 mc_ch_readl(const struct tegra_mc *mc, int ch,
unsigned long offset)
{
- if (!mc->bcast_ch_regs)
- return 0;
-
- if (ch == MC_BROADCAST_CHANNEL)
+ if (ch == MC_BROADCAST_CHANNEL) {
+ if (!mc->bcast_ch_regs)
+ return 0;
return readl_relaxed(mc->bcast_ch_regs + offset);
+ } else if (mc->ch_regs) {
+ return readl_relaxed(mc->ch_regs[ch] + offset);
+ }

- return readl_relaxed(mc->ch_regs[ch] + offset);
+ return 0;
}

static inline void mc_ch_writel(const struct tegra_mc *mc, int ch,
u32 value, unsigned long offset)
{
- if (!mc->bcast_ch_regs)
- return;
-
- if (ch == MC_BROADCAST_CHANNEL)
+ if (ch == MC_BROADCAST_CHANNEL) {
+ if (!mc->bcast_ch_regs)
+ return;
writel_relaxed(value, mc->bcast_ch_regs + offset);
- else
+ } else if (mc->ch_regs) {
writel_relaxed(value, mc->ch_regs[ch] + offset);
+ }
}

static inline u32 mc_readl(const struct tegra_mc *mc, unsigned long offset)
diff --git a/drivers/memory/tegra/tegra186.c b/drivers/memory/tegra/tegra186.c
index 1b3183951bfe..716582255eeb 100644
--- a/drivers/memory/tegra/tegra186.c
+++ b/drivers/memory/tegra/tegra186.c
@@ -26,20 +26,16 @@
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];
+ char name[14];
int err;

- mc->bcast_ch_regs = devm_platform_ioremap_resource_byname(pdev, "broadcast");
- 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);
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "broadcast");
+ if (res) {
+ mc->bcast_ch_regs = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(mc->bcast_ch_regs))
+ return PTR_ERR(mc->bcast_ch_regs);
}

mc->ch_regs = devm_kcalloc(mc->dev, mc->soc->num_channels, sizeof(*mc->ch_regs),
@@ -55,7 +51,6 @@ static int tegra186_mc_probe(struct tegra_mc *mc)
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;
@@ -121,6 +116,9 @@ static int tegra186_mc_probe_device(struct tegra_mc *mc, struct device *dev)
if (!tegra_dev_iommu_get_stream_id(dev, &sid))
return 0;

+ if (!mc->regs)
+ 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) {
@@ -146,6 +144,9 @@ static int tegra186_mc_resume(struct tegra_mc *mc)
#if IS_ENABLED(CONFIG_IOMMU_API)
unsigned int i;

+ if (!mc->regs)
+ return 0;
+
for (i = 0; i < mc->soc->num_clients; i++) {
const struct tegra_mc_client *client = &mc->soc->clients[i];

--
2.17.1