clk: tegra: MBIST work around for Tegra210

Tegra210 has a hw bug which can cause IP blocks to lock up when ungating a
domain. The reason is that the logic responsible for resetting the memory
built-in self test mode can come up in an undefined state because its
clock is gated by a second level clock gate (SLCG). Work around this by
making sure the logic will get some clock edges by ensuring the relevant
clock is enabled and temporarily override the relevant SLCGs.
Unfortunately for some IP blocks, the control bits for overriding the
SLCGs are not in CAR, but in the IP block itself. This means we need to
map a few extra register banks in the clock code.

Signed-off-by: Peter De Schrijver <[e-mail]>
Reviewed-by: Jon Hunter <[e-mail]>
Tested-by: Jon Hunter <[e-mail]>
Tested-by: Hector Martin <[e-mail]>
Tested-by: Andre Heider <[e-mail]>
Tested-by: Mikko Perttunen <[e-mail]>
Signed-off-by: Thierry Reding <[e-mail]>

fixup mbist

drivers/clk/tegra/clk-tegra210.c

···
 #include <linux/of_address.h>
 #include <linux/delay.h>
 #include <linux/export.h>
+#include <linux/mutex.h>
 #include <linux/clk/tegra.h>
 #include <dt-bindings/clock/tegra210-car.h>
 #include <dt-bindings/reset/tegra210-car.h>
 #include <linux/iopoll.h>
+#include <soc/tegra/pmc.h>
 
 #include "clk.h"
 #include "clk-id.h"
···
 #define CLK_RST_CONTROLLER_RST_DEV_Y_SET 0x2a8
 #define CLK_RST_CONTROLLER_RST_DEV_Y_CLR 0x2ac
 
+#define LVL2_CLK_GATE_OVRA 0xf8
+#define LVL2_CLK_GATE_OVRC 0x3a0
+#define LVL2_CLK_GATE_OVRD 0x3a4
+#define LVL2_CLK_GATE_OVRE 0x554
+
+/* I2S registers to handle during APE MBIST WAR */
+#define TEGRA210_I2S_BASE  0x1000
+#define TEGRA210_I2S_SIZE  0x100
+#define TEGRA210_I2S_CTRLS 5
+#define TEGRA210_I2S_CG    0x88
+#define TEGRA210_I2S_CTRL  0xa0
+
+/* DISPA registers to handle during MBIST WAR */
+#define DC_CMD_DISPLAY_COMMAND 0xc8
+#define DC_COM_DSC_TOP_CTL 0xcf8
+
+/* VIC register to handle during MBIST WAR */
+#define NV_PVIC_THI_SLCG_OVERRIDE_LOW 0x8c
+
+/* APE, DISPA and VIC base addesses needed for MBIST WAR */
+#define TEGRA210_AHUB_BASE  0x702d0000
+#define TEGRA210_DISPA_BASE 0x54200000
+#define TEGRA210_VIC_BASE  0x54340000
+
 /*
  * SDM fractional divisor is 16-bit 2's complement signed number within
  * (-2^12 ... 2^12-1) range. Represented in PLL data structure as unsigned
···
 } tegra210_cpu_clk_sctx;
 #endif
 
+struct tegra210_domain_mbist_war {
+	void (*handle_lvl2_ovr)(struct tegra210_domain_mbist_war *mbist);
+	const u32 lvl2_offset;
+	const u32 lvl2_mask;
+	const unsigned int num_clks;
+	const unsigned int *clk_init_data;
+	struct clk_bulk_data *clks;
+};
+
+static struct clk **clks;
+
 static void __iomem *clk_base;
 static void __iomem *pmc_base;
+static void __iomem *ahub_base;
+static void __iomem *dispa_base;
+static void __iomem *vic_base;
 
 static unsigned long osc_freq;
 static unsigned long pll_ref_freq;
···
 static DEFINE_SPINLOCK(pll_u_lock);
 static DEFINE_SPINLOCK(sor1_lock);
 static DEFINE_SPINLOCK(emc_lock);
+static DEFINE_MUTEX(lvl2_ovr_lock);
 
 /* possible OSC frequencies in Hz */
 static unsigned long tegra210_input_freq[] = {
···
 #define PLLA_MISC2_WRITE_MASK		0x06ffffff
 
 /* PLLD */
+#define PLLD_BASE_CSI_CLKSOURCE		(1 << 23)
+
 #define PLLD_MISC0_EN_SDM		(1 << 16)
 #define PLLD_MISC0_LOCK_OVERRIDE	(1 << 17)
 #define PLLD_MISC0_LOCK_ENABLE		(1 << 18)
···
 	writel_relaxed(val, clk_base + SATA_PLL_CFG0);
 }
 EXPORT_SYMBOL_GPL(tegra210_set_sata_pll_seq_sw);
+
+static void tegra210_generic_mbist_war(struct tegra210_domain_mbist_war *mbist)
+{
+	u32 val;
+
+	val = readl_relaxed(clk_base + mbist->lvl2_offset);
+	writel_relaxed(val | mbist->lvl2_mask, clk_base + mbist->lvl2_offset);
+	fence_udelay(1, clk_base);
+	writel_relaxed(val, clk_base + mbist->lvl2_offset);
+	fence_udelay(1, clk_base);
+}
+
+static void tegra210_venc_mbist_war(struct tegra210_domain_mbist_war *mbist)
+{
+	u32 csi_src, ovra, ovre;
+	unsigned long flags = 0;
+
+	spin_lock_irqsave(&pll_d_lock, flags);
+
+	csi_src = readl_relaxed(clk_base + PLLD_BASE);
+	writel_relaxed(csi_src | PLLD_BASE_CSI_CLKSOURCE, clk_base + PLLD_BASE);
+	fence_udelay(1, clk_base);
+
+	ovra = readl_relaxed(clk_base + LVL2_CLK_GATE_OVRA);
+	writel_relaxed(ovra | BIT(15), clk_base + LVL2_CLK_GATE_OVRA);
+	ovre = readl_relaxed(clk_base + LVL2_CLK_GATE_OVRE);
+	writel_relaxed(ovre | BIT(3), clk_base + LVL2_CLK_GATE_OVRE);
+	fence_udelay(1, clk_base);
+
+	writel_relaxed(ovra, clk_base + LVL2_CLK_GATE_OVRA);
+	writel_relaxed(ovre, clk_base + LVL2_CLK_GATE_OVRE);
+	writel_relaxed(csi_src, clk_base + PLLD_BASE);
+	fence_udelay(1, clk_base);
+
+	spin_unlock_irqrestore(&pll_d_lock, flags);
+}
+
+static void tegra210_disp_mbist_war(struct tegra210_domain_mbist_war *mbist)
+{
+	u32 ovra, dsc_top_ctrl;
+
+	ovra = readl_relaxed(clk_base + LVL2_CLK_GATE_OVRA);
+	writel_relaxed(ovra | BIT(1), clk_base + LVL2_CLK_GATE_OVRA);
+	fence_udelay(1, clk_base);
+
+	dsc_top_ctrl = readl_relaxed(dispa_base + DC_COM_DSC_TOP_CTL);
+	writel_relaxed(dsc_top_ctrl | BIT(2), dispa_base + DC_COM_DSC_TOP_CTL);
+	readl_relaxed(dispa_base + DC_CMD_DISPLAY_COMMAND);
+	writel_relaxed(dsc_top_ctrl, dispa_base + DC_COM_DSC_TOP_CTL);
+	readl_relaxed(dispa_base + DC_CMD_DISPLAY_COMMAND);
+
+	writel_relaxed(ovra, clk_base + LVL2_CLK_GATE_OVRA);
+	fence_udelay(1, clk_base);
+}
+
+static void tegra210_vic_mbist_war(struct tegra210_domain_mbist_war *mbist)
+{
+	u32 ovre, val;
+
+	ovre = readl_relaxed(clk_base + LVL2_CLK_GATE_OVRE);
+	writel_relaxed(ovre | BIT(5), clk_base + LVL2_CLK_GATE_OVRE);
+	fence_udelay(1, clk_base);
+
+	val = readl_relaxed(vic_base + NV_PVIC_THI_SLCG_OVERRIDE_LOW);
+	writel_relaxed(val | BIT(0) | GENMASK(7, 2) | BIT(24),
+			vic_base + NV_PVIC_THI_SLCG_OVERRIDE_LOW);
+	fence_udelay(1, vic_base + NV_PVIC_THI_SLCG_OVERRIDE_LOW);
+
+	writel_relaxed(val, vic_base + NV_PVIC_THI_SLCG_OVERRIDE_LOW);
+	readl(vic_base + NV_PVIC_THI_SLCG_OVERRIDE_LOW);
+
+	writel_relaxed(ovre, clk_base + LVL2_CLK_GATE_OVRE);
+	fence_udelay(1, clk_base);
+}
+
+static void tegra210_ape_mbist_war(struct tegra210_domain_mbist_war *mbist)
+{
+	void __iomem *i2s_base;
+	unsigned int i;
+	u32 ovrc, ovre;
+
+	ovrc = readl_relaxed(clk_base + LVL2_CLK_GATE_OVRC);
+	ovre = readl_relaxed(clk_base + LVL2_CLK_GATE_OVRE);
+	writel_relaxed(ovrc | BIT(1), clk_base + LVL2_CLK_GATE_OVRC);
+	writel_relaxed(ovre | BIT(10) | BIT(11),
+			clk_base + LVL2_CLK_GATE_OVRE);
+	fence_udelay(1, clk_base);
+
+	i2s_base = ahub_base + TEGRA210_I2S_BASE;
+
+	for (i = 0; i < TEGRA210_I2S_CTRLS; i++) {
+		u32 i2s_ctrl;
+
+		i2s_ctrl = readl_relaxed(i2s_base + TEGRA210_I2S_CTRL);
+		writel_relaxed(i2s_ctrl | BIT(10),
+				i2s_base + TEGRA210_I2S_CTRL);
+		writel_relaxed(0, i2s_base + TEGRA210_I2S_CG);
+		readl(i2s_base + TEGRA210_I2S_CG);
+		writel_relaxed(1, i2s_base + TEGRA210_I2S_CG);
+		writel_relaxed(i2s_ctrl, i2s_base + TEGRA210_I2S_CTRL);
+		readl(i2s_base + TEGRA210_I2S_CTRL);
+
+		i2s_base += TEGRA210_I2S_SIZE;
+	}
+
+	writel_relaxed(ovrc, clk_base + LVL2_CLK_GATE_OVRC);
+	writel_relaxed(ovre, clk_base + LVL2_CLK_GATE_OVRE);
+	fence_udelay(1, clk_base);
+}
 
 static inline void _pll_misc_chk_default(void __iomem *base,
 					struct tegra_clk_pll_params *params,
···
 	{ "pll_a1", &pll_a1_params, tegra_clk_pll_a1, "pll_ref" },
 };
 
-static struct clk **clks;
-
 static const char * const aclk_parents[] = {
 	"pll_a1", "pll_c", "pll_p", "pll_a_out0", "pll_c2", "pll_c3",
 	"clk_m"
 };
+
+static const unsigned int nvjpg_slcg_clkids[] = { TEGRA210_CLK_NVDEC };
+static const unsigned int nvdec_slcg_clkids[] = { TEGRA210_CLK_NVJPG };
+static const unsigned int sor_slcg_clkids[] = { TEGRA210_CLK_HDA2CODEC_2X,
+	TEGRA210_CLK_HDA2HDMI, TEGRA210_CLK_DISP1, TEGRA210_CLK_DISP2 };
+static const unsigned int disp_slcg_clkids[] = { TEGRA210_CLK_LA,
+	TEGRA210_CLK_HOST1X};
+static const unsigned int xusba_slcg_clkids[] = { TEGRA210_CLK_XUSB_HOST,
+	TEGRA210_CLK_XUSB_DEV };
+static const unsigned int xusbb_slcg_clkids[] = { TEGRA210_CLK_XUSB_HOST,
+	TEGRA210_CLK_XUSB_SS };
+static const unsigned int xusbc_slcg_clkids[] = { TEGRA210_CLK_XUSB_DEV,
+	TEGRA210_CLK_XUSB_SS };
+static const unsigned int venc_slcg_clkids[] = { TEGRA210_CLK_HOST1X,
+	TEGRA210_CLK_PLL_D };
+static const unsigned int ape_slcg_clkids[] = { TEGRA210_CLK_ACLK,
+	TEGRA210_CLK_I2S0, TEGRA210_CLK_I2S1, TEGRA210_CLK_I2S2,
+	TEGRA210_CLK_I2S3, TEGRA210_CLK_I2S4, TEGRA210_CLK_SPDIF_OUT,
+	TEGRA210_CLK_D_AUDIO };
+static const unsigned int vic_slcg_clkids[] = { TEGRA210_CLK_HOST1X };
+
+static struct tegra210_domain_mbist_war tegra210_pg_mbist_war[] = {
+	[TEGRA_POWERGATE_VENC] = {
+		.handle_lvl2_ovr = tegra210_venc_mbist_war,
+		.num_clks = ARRAY_SIZE(venc_slcg_clkids),
+		.clk_init_data = venc_slcg_clkids,
+	},
+	[TEGRA_POWERGATE_SATA] = {
+		.handle_lvl2_ovr = tegra210_generic_mbist_war,
+		.lvl2_offset = LVL2_CLK_GATE_OVRC,
+		.lvl2_mask = BIT(0) | BIT(17) | BIT(19),
+	},
+	[TEGRA_POWERGATE_MPE] = {
+		.handle_lvl2_ovr = tegra210_generic_mbist_war,
+		.lvl2_offset = LVL2_CLK_GATE_OVRE,
+		.lvl2_mask = BIT(2),
+	},
+	[TEGRA_POWERGATE_SOR] = {
+		.handle_lvl2_ovr = tegra210_generic_mbist_war,
+		.num_clks = ARRAY_SIZE(sor_slcg_clkids),
+		.clk_init_data = sor_slcg_clkids,
+		.lvl2_offset = LVL2_CLK_GATE_OVRA,
+		.lvl2_mask = BIT(1) | BIT(2),
+	},
+	[TEGRA_POWERGATE_DIS] = {
+		.handle_lvl2_ovr = tegra210_disp_mbist_war,
+		.num_clks = ARRAY_SIZE(disp_slcg_clkids),
+		.clk_init_data = disp_slcg_clkids,
+	},
+	[TEGRA_POWERGATE_DISB] = {
+		.num_clks = ARRAY_SIZE(disp_slcg_clkids),
+		.clk_init_data = disp_slcg_clkids,
+		.handle_lvl2_ovr = tegra210_generic_mbist_war,
+		.lvl2_offset = LVL2_CLK_GATE_OVRA,
+		.lvl2_mask = BIT(2),
+	},
+	[TEGRA_POWERGATE_XUSBA] = {
+		.num_clks = ARRAY_SIZE(xusba_slcg_clkids),
+		.clk_init_data = xusba_slcg_clkids,
+		.handle_lvl2_ovr = tegra210_generic_mbist_war,
+		.lvl2_offset = LVL2_CLK_GATE_OVRC,
+		.lvl2_mask = BIT(30) | BIT(31),
+	},
+	[TEGRA_POWERGATE_XUSBB] = {
+		.num_clks = ARRAY_SIZE(xusbb_slcg_clkids),
+		.clk_init_data = xusbb_slcg_clkids,
+		.handle_lvl2_ovr = tegra210_generic_mbist_war,
+		.lvl2_offset = LVL2_CLK_GATE_OVRC,
+		.lvl2_mask = BIT(30) | BIT(31),
+	},
+	[TEGRA_POWERGATE_XUSBC] = {
+		.num_clks = ARRAY_SIZE(xusbc_slcg_clkids),
+		.clk_init_data = xusbc_slcg_clkids,
+		.handle_lvl2_ovr = tegra210_generic_mbist_war,
+		.lvl2_offset = LVL2_CLK_GATE_OVRC,
+		.lvl2_mask = BIT(30) | BIT(31),
+	},
+	[TEGRA_POWERGATE_VIC] = {
+		.num_clks = ARRAY_SIZE(vic_slcg_clkids),
+		.clk_init_data = vic_slcg_clkids,
+		.handle_lvl2_ovr = tegra210_vic_mbist_war,
+	},
+	[TEGRA_POWERGATE_NVDEC] = {
+		.num_clks = ARRAY_SIZE(nvdec_slcg_clkids),
+		.clk_init_data = nvdec_slcg_clkids,
+		.handle_lvl2_ovr = tegra210_generic_mbist_war,
+		.lvl2_offset = LVL2_CLK_GATE_OVRC,
+		.lvl2_mask = BIT(9) | BIT(31),
+	},
+	[TEGRA_POWERGATE_NVJPG] = {
+		.num_clks = ARRAY_SIZE(nvjpg_slcg_clkids),
+		.clk_init_data = nvjpg_slcg_clkids,
+		.handle_lvl2_ovr = tegra210_generic_mbist_war,
+		.lvl2_offset = LVL2_CLK_GATE_OVRC,
+		.lvl2_mask = BIT(9) | BIT(31),
+	},
+	[TEGRA_POWERGATE_AUD] = {
+		.num_clks = ARRAY_SIZE(ape_slcg_clkids),
+		.clk_init_data = ape_slcg_clkids,
+		.handle_lvl2_ovr = tegra210_ape_mbist_war,
+	},
+	[TEGRA_POWERGATE_VE2] = {
+		.handle_lvl2_ovr = tegra210_generic_mbist_war,
+		.lvl2_offset = LVL2_CLK_GATE_OVRD,
+		.lvl2_mask = BIT(22),
+	},
+};
+
+int tegra210_clk_handle_mbist_war(unsigned int id)
+{
+	int err;
+	struct tegra210_domain_mbist_war *mbist_war;
+
+	if (id >= ARRAY_SIZE(tegra210_pg_mbist_war)) {
+		WARN(1, "unknown domain id in MBIST WAR handler\n");
+		return -EINVAL;
+	}
+
+	mbist_war = &tegra210_pg_mbist_war[id];
+	if (!mbist_war->handle_lvl2_ovr)
+		return 0;
+
+	if (mbist_war->num_clks && !mbist_war->clks)
+		return -ENODEV;
+
+	err = clk_bulk_prepare_enable(mbist_war->num_clks, mbist_war->clks);
+	if (err < 0)
+		return err;
+
+	mutex_lock(&lvl2_ovr_lock);
+
+	mbist_war->handle_lvl2_ovr(mbist_war);
+
+	mutex_unlock(&lvl2_ovr_lock);
+
+	clk_bulk_disable_unprepare(mbist_war->num_clks, mbist_war->clks);
+
+	return 0;
+}
 
 void tegra210_put_utmipll_in_iddq(void)
 {
···
 	return 0;
 }
 
+static void tegra210_mbist_clk_init(void)
+{
+	unsigned int i, j;
+
+	for (i = 0; i < ARRAY_SIZE(tegra210_pg_mbist_war); i++) {
+		unsigned int num_clks = tegra210_pg_mbist_war[i].num_clks;
+		struct clk_bulk_data *clk_data;
+
+		if (!num_clks)
+			continue;
+
+		clk_data = kmalloc_array(num_clks, sizeof(*clk_data),
+					 GFP_KERNEL);
+		if (WARN_ON(!clk_data))
+			return;
+
+		tegra210_pg_mbist_war[i].clks = clk_data;
+		for (j = 0; j < num_clks; j++) {
+			int clk_id = tegra210_pg_mbist_war[i].clk_init_data[j];
+			struct clk *clk = clks[clk_id];
+
+			if (WARN(IS_ERR(clk), "clk_id: %d\n", clk_id)) {
+				kfree(clk_data);
+				tegra210_pg_mbist_war[i].clks = NULL;
+				break;
+			}
+			clk_data[j].clk = clk;
+		}
+	}
+}
+
 /**
  * tegra210_clock_init - Tegra210-specific clock initialization
  * @np: struct device_node * of the DT node for the SoC CAR IP block
···
 	if (!pmc_base) {
 		pr_err("Can't map pmc registers\n");
 		WARN_ON(1);
+		return;
+	}
+
+	ahub_base = ioremap(TEGRA210_AHUB_BASE, SZ_64K);
+	if (!ahub_base) {
+		pr_err("ioremap tegra210 APE failed\n");
+		return;
+	}
+
+	dispa_base = ioremap(TEGRA210_DISPA_BASE, SZ_256K);
+	if (!dispa_base) {
+		pr_err("ioremap tegra210 DISPA failed\n");
+		return;
+	}
+
+	vic_base = ioremap(TEGRA210_VIC_BASE, SZ_256K);
+	if (!vic_base) {
+		pr_err("ioremap tegra210 VIC failed\n");
 		return;
 	}
 
···
 
 	tegra_add_of_provider(np);
 	tegra_register_devclks(devclks, ARRAY_SIZE(devclks));
+
+	tegra210_mbist_clk_init();
 
 	tegra_cpu_car_ops = &tegra210_cpu_car_ops;
 }

include/linux/clk/tegra.h

···
 extern void tegra210_set_sata_pll_seq_sw(bool state);
 extern void tegra210_put_utmipll_in_iddq(void);
 extern void tegra210_put_utmipll_out_iddq(void);
+extern int tegra210_clk_handle_mbist_war(unsigned int id);
 
 #endif /* __LINUX_CLK_TEGRA_H_ */