Commit e247deae authored by Mikko Perttunen's avatar Mikko Perttunen Committed by Thierry Reding
Browse files

soc/tegra: pmc: Support systems where PMC is marked secure 



On Tegra210 systems with new enough boot software, direct register
accesses to PMC register space from the non-secure world are not
allowed. Instead a monitor call may be used to read and write PMC
registers.

Add code to detect such a system by attempting to write a scratch
register and detecting if the write happened or not. If not, we switch
to doing all register accesses through the monitor call.

Signed-off-by: default avatarMikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
Acked-by: default avatarJon Hunter <jonathanh@nvidia.com>
parent fa3bc04e

drivers/soc/tegra/pmc.c

+97 −3
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 


#define pr_fmt(fmt) "tegra-pmc: " fmt



#include <linux/arm-smccc.h>

#include <linux/clk.h>

#include <linux/clk/tegra.h>

#include <linux/debugfs.h>
@@ -145,6 +146,11 @@ 
#define WAKE_AOWAKE_CTRL 0x4f4

#define  WAKE_AOWAKE_CTRL_INTR_POLARITY BIT(0)



/* for secure PMC */

#define TEGRA_SMC_PMC		0xc2fffe00

#define  TEGRA_SMC_PMC_READ	0xaa

#define  TEGRA_SMC_PMC_WRITE	0xbb



struct tegra_powergate {

	struct generic_pm_domain genpd;

	struct tegra_pmc *pmc;
@@ -216,6 +222,7 @@ struct tegra_pmc_soc { 
	bool has_gpu_clamps;

	bool needs_mbist_war;

	bool has_impl_33v_pwr;

	bool maybe_tz_only;



	const struct tegra_io_pad_soc *io_pads;

	unsigned int num_io_pads;
@@ -278,6 +285,7 @@ static const char * const tegra30_reset_sources[] = { 
 * @scratch: pointer to I/O remapped region for scratch registers

 * @clk: pointer to pclk clock

 * @soc: pointer to SoC data structure

 * @tz_only: flag specifying if the PMC can only be accessed via TrustZone

 * @debugfs: pointer to debugfs entry

 * @rate: currently configured rate of pclk

 * @suspend_mode: lowest suspend mode available
@@ -308,6 +316,7 @@ struct tegra_pmc { 
	struct dentry *debugfs;



	const struct tegra_pmc_soc *soc;

	bool tz_only;



	unsigned long rate;
@@ -346,14 +355,63 @@ to_powergate(struct generic_pm_domain *domain) 


static u32 tegra_pmc_readl(struct tegra_pmc *pmc, unsigned long offset)

{

	struct arm_smccc_res res;



	if (pmc->tz_only) {

		arm_smccc_smc(TEGRA_SMC_PMC, TEGRA_SMC_PMC_READ, offset, 0, 0,

			      0, 0, 0, &res);

		if (res.a0) {

			if (pmc->dev)

				dev_warn(pmc->dev, "%s(): SMC failed: %lu\n",

					 __func__, res.a0);

			else

				pr_warn("%s(): SMC failed: %lu\n", __func__,

					res.a0);

		}



		return res.a1;

	}



	return readl(pmc->base + offset);

}



static void tegra_pmc_writel(struct tegra_pmc *pmc, u32 value,

			     unsigned long offset)

{

	struct arm_smccc_res res;



	if (pmc->tz_only) {

		arm_smccc_smc(TEGRA_SMC_PMC, TEGRA_SMC_PMC_WRITE, offset,

			      value, 0, 0, 0, 0, &res);

		if (res.a0) {

			if (pmc->dev)

				dev_warn(pmc->dev, "%s(): SMC failed: %lu\n",

					 __func__, res.a0);

			else

				pr_warn("%s(): SMC failed: %lu\n", __func__,

					res.a0);

		}

	} else {

		writel(value, pmc->base + offset);

	}

}



static u32 tegra_pmc_scratch_readl(struct tegra_pmc *pmc, unsigned long offset)

{

	if (pmc->tz_only)

		return tegra_pmc_readl(pmc, offset);



	return readl(pmc->scratch + offset);

}



static void tegra_pmc_scratch_writel(struct tegra_pmc *pmc, u32 value,

				     unsigned long offset)

{

	if (pmc->tz_only)

		tegra_pmc_writel(pmc, value, offset);

	else

		writel(value, pmc->scratch + offset);

}



/*

 * TODO Figure out a way to call this with the struct tegra_pmc * passed in.
@@ -776,7 +834,7 @@ static int tegra_pmc_restart_notify(struct notifier_block *this, 
	const char *cmd = data;

	u32 value;



	value = readl(pmc->scratch + pmc->soc->regs->scratch0);

	value = tegra_pmc_scratch_readl(pmc, pmc->soc->regs->scratch0);

	value &= ~PMC_SCRATCH0_MODE_MASK;



	if (cmd) {
@@ -790,7 +848,7 @@ static int tegra_pmc_restart_notify(struct notifier_block *this, 
			value |= PMC_SCRATCH0_MODE_RCM;

	}



	writel(value, pmc->scratch + pmc->soc->regs->scratch0);

	tegra_pmc_scratch_writel(pmc, value, pmc->soc->regs->scratch0);



	/* reset everything but PMC_SCRATCH0 and PMC_RST_STATUS */

	value = tegra_pmc_readl(pmc, PMC_CNTRL);
@@ -2071,6 +2129,7 @@ static const struct tegra_pmc_soc tegra20_pmc_soc = { 
	.has_gpu_clamps = false,

	.needs_mbist_war = false,

	.has_impl_33v_pwr = false,

	.maybe_tz_only = false,

	.num_io_pads = 0,

	.io_pads = NULL,

	.num_pin_descs = 0,
@@ -2117,6 +2176,7 @@ static const struct tegra_pmc_soc tegra30_pmc_soc = { 
	.has_gpu_clamps = false,

	.needs_mbist_war = false,

	.has_impl_33v_pwr = false,

	.maybe_tz_only = false,

	.num_io_pads = 0,

	.io_pads = NULL,

	.num_pin_descs = 0,
@@ -2167,6 +2227,7 @@ static const struct tegra_pmc_soc tegra114_pmc_soc = { 
	.has_gpu_clamps = false,

	.needs_mbist_war = false,

	.has_impl_33v_pwr = false,

	.maybe_tz_only = false,

	.num_io_pads = 0,

	.io_pads = NULL,

	.num_pin_descs = 0,
@@ -2277,6 +2338,7 @@ static const struct tegra_pmc_soc tegra124_pmc_soc = { 
	.has_gpu_clamps = true,

	.needs_mbist_war = false,

	.has_impl_33v_pwr = false,

	.maybe_tz_only = false,

	.num_io_pads = ARRAY_SIZE(tegra124_io_pads),

	.io_pads = tegra124_io_pads,

	.num_pin_descs = ARRAY_SIZE(tegra124_pin_descs),
@@ -2382,6 +2444,7 @@ static const struct tegra_pmc_soc tegra210_pmc_soc = { 
	.has_gpu_clamps = true,

	.needs_mbist_war = true,

	.has_impl_33v_pwr = false,

	.maybe_tz_only = true,

	.num_io_pads = ARRAY_SIZE(tegra210_io_pads),

	.io_pads = tegra210_io_pads,

	.num_pin_descs = ARRAY_SIZE(tegra210_pin_descs),
@@ -2506,6 +2569,7 @@ static const struct tegra_pmc_soc tegra186_pmc_soc = { 
	.has_gpu_clamps = false,

	.needs_mbist_war = false,

	.has_impl_33v_pwr = true,

	.maybe_tz_only = false,

	.num_io_pads = ARRAY_SIZE(tegra186_io_pads),

	.io_pads = tegra186_io_pads,

	.num_pin_descs = ARRAY_SIZE(tegra186_pin_descs),
@@ -2585,6 +2649,7 @@ static const struct tegra_pmc_soc tegra194_pmc_soc = { 
	.has_gpu_clamps = false,

	.needs_mbist_war = false,

	.has_impl_33v_pwr = false,

	.maybe_tz_only = false,

	.num_io_pads = ARRAY_SIZE(tegra194_io_pads),

	.io_pads = tegra194_io_pads,

	.regs = &tegra186_pmc_regs,
@@ -2619,6 +2684,32 @@ static struct platform_driver tegra_pmc_driver = { 
};

builtin_platform_driver(tegra_pmc_driver);



static bool __init tegra_pmc_detect_tz_only(struct tegra_pmc *pmc)

{

	u32 value, saved;



	saved = readl(pmc->base + pmc->soc->regs->scratch0);

	value = saved ^ 0xffffffff;



	if (value == 0xffffffff)

		value = 0xdeadbeef;



	/* write pattern and read it back */

	writel(value, pmc->base + pmc->soc->regs->scratch0);

	value = readl(pmc->base + pmc->soc->regs->scratch0);



	/* if we read all-zeroes, access is restricted to TZ only */

	if (value == 0) {

		pr_info("access to PMC is restricted to TZ\n");

		return true;

	}



	/* restore original value */

	writel(saved, pmc->base + pmc->soc->regs->scratch0);



	return false;

}



/*

 * Early initialization to allow access to registers in the very early boot

 * process.
@@ -2681,6 +2772,9 @@ static int __init tegra_pmc_early_init(void) 
	if (np) {

		pmc->soc = match->data;



		if (pmc->soc->maybe_tz_only)

			pmc->tz_only = tegra_pmc_detect_tz_only(pmc);



		tegra_powergate_init(pmc, np);



		/*

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