[PATCH v2 2/2] remoteproc: imx_rproc: Switch iMX8MN/MP from SMCCC to MMIO

[Marek Vasut]

The MX8M CM7 boot via SMC call is problematic, since not all versions
of ATF support this interface. Extend the MMIO support so it can boot
the CM7 on MX8MN/MP instead and discern the two alternatives using DT
compatible strings.

Signed-off-by: Marek Vasut <marex at denx.de>
---
Cc: Bjorn Andersson <andersson at kernel.org>
Cc: Conor Dooley <conor+dt at kernel.org>
Cc: Fabio Estevam <festevam at gmail.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt at linaro.org>
Cc: Mathieu Poirier <mathieu.poirier at linaro.org>
Cc: NXP Linux Team <linux-imx at nxp.com>
Cc: Peng Fan <peng.fan at nxp.com>
Cc: Pengutronix Kernel Team <kernel at pengutronix.de>
Cc: Rob Herring <robh+dt at kernel.org>
Cc: Sascha Hauer <s.hauer at pengutronix.de>
Cc: Shawn Guo <shawnguo at kernel.org>
Cc: devicetree at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-remoteproc at vger.kernel.org
---
V2: Rename 'gpr' to 'fsl,iomuxc-gpr'
---
 drivers/remoteproc/imx_rproc.c | 58 ++++++++++++++++++++++++++++++++--
 drivers/remoteproc/imx_rproc.h |  2 ++
 2 files changed, 58 insertions(+), 2 deletions(-)

diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
index 4ee2646ce62ad..8bb293b9f327c 100644
--- a/drivers/remoteproc/imx_rproc.c
+++ b/drivers/remoteproc/imx_rproc.c
@@ -40,6 +40,12 @@
 #define IMX7D_M4_STOP			(IMX7D_ENABLE_M4 | IMX7D_SW_M4C_RST | \
 					 IMX7D_SW_M4C_NON_SCLR_RST)
 
+#define IMX8M_M7_STOP			(IMX7D_ENABLE_M4 | IMX7D_SW_M4C_RST)
+#define IMX8M_M7_POLL			IMX7D_ENABLE_M4
+
+#define IMX8M_GPR22			0x58
+#define IMX8M_GPR22_CM7_CPUWAIT		BIT(0)
+
 /* Address: 0x020D8000 */
 #define IMX6SX_SRC_SCR			0x00
 #define IMX6SX_ENABLE_M4		BIT(22)
@@ -91,6 +97,7 @@ static int imx_rproc_detach_pd(struct rproc *rproc);
 struct imx_rproc {
 	struct device			*dev;
 	struct regmap			*regmap;
+	struct regmap			*gpr;
 	struct rproc			*rproc;
 	const struct imx_rproc_dcfg	*dcfg;
 	struct imx_rproc_mem		mem[IMX_RPROC_MEM_MAX];
@@ -285,6 +292,18 @@ static const struct imx_rproc_att imx_rproc_att_imx6sx[] = {
 	{ 0x80000000, 0x80000000, 0x60000000, 0 },
 };
 
+static const struct imx_rproc_dcfg imx_rproc_cfg_imx8mn_mmio = {
+	.src_reg	= IMX7D_SRC_SCR,
+	.src_mask	= IMX7D_M4_RST_MASK,
+	.src_start	= IMX7D_M4_START,
+	.src_stop	= IMX8M_M7_STOP,
+	.gpr_reg	= IMX8M_GPR22,
+	.gpr_wait	= IMX8M_GPR22_CM7_CPUWAIT,
+	.att		= imx_rproc_att_imx8mn,
+	.att_size	= ARRAY_SIZE(imx_rproc_att_imx8mn),
+	.method		= IMX_RPROC_MMIO,
+};
+
 static const struct imx_rproc_dcfg imx_rproc_cfg_imx8mn = {
 	.att		= imx_rproc_att_imx8mn,
 	.att_size	= ARRAY_SIZE(imx_rproc_att_imx8mn),
@@ -365,8 +384,14 @@ static int imx_rproc_start(struct rproc *rproc)
 
 	switch (dcfg->method) {
 	case IMX_RPROC_MMIO:
-		ret = regmap_update_bits(priv->regmap, dcfg->src_reg, dcfg->src_mask,
-					 dcfg->src_start);
+		if (priv->gpr) {
+			ret = regmap_clear_bits(priv->gpr, dcfg->gpr_reg,
+						dcfg->gpr_wait);
+		} else {
+			ret = regmap_update_bits(priv->regmap, dcfg->src_reg,
+						 dcfg->src_mask,
+						 dcfg->src_start);
+		}
 		break;
 	case IMX_RPROC_SMC:
 		arm_smccc_smc(IMX_SIP_RPROC, IMX_SIP_RPROC_START, 0, 0, 0, 0, 0, 0, &res);
@@ -395,6 +420,16 @@ static int imx_rproc_stop(struct rproc *rproc)
 
 	switch (dcfg->method) {
 	case IMX_RPROC_MMIO:
+		if (priv->gpr) {
+			ret = regmap_set_bits(priv->gpr, dcfg->gpr_reg,
+					      dcfg->gpr_wait);
+			if (ret) {
+				dev_err(priv->dev,
+					"Failed to quiescence M4 platform!\n");
+				return ret;
+			}
+		}
+
 		ret = regmap_update_bits(priv->regmap, dcfg->src_reg, dcfg->src_mask,
 					 dcfg->src_stop);
 		break;
@@ -992,6 +1027,10 @@ static int imx_rproc_detect_mode(struct imx_rproc *priv)
 		break;
 	}
 
+	priv->gpr = syscon_regmap_lookup_by_phandle(dev->of_node, "fsl,iomuxc-gpr");
+	if (IS_ERR(priv->gpr))
+		priv->gpr = NULL;
+
 	regmap = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
 	if (IS_ERR(regmap)) {
 		dev_err(dev, "failed to find syscon\n");
@@ -1001,6 +1040,19 @@ static int imx_rproc_detect_mode(struct imx_rproc *priv)
 	priv->regmap = regmap;
 	regmap_attach_dev(dev, regmap, &config);
 
+	if (priv->gpr) {
+		ret = regmap_read(priv->gpr, dcfg->gpr_reg, &val);
+		if (val & dcfg->gpr_wait) {
+			/*
+			 * After cold boot, the CM indicates its in wait
+			 * state, but not fully powered off. Power it off
+			 * fully so firmware can be loaded into it.
+			 */
+			imx_rproc_stop(priv->rproc);
+			return 0;
+		}
+	}
+
 	ret = regmap_read(regmap, dcfg->src_reg, &val);
 	if (ret) {
 		dev_err(dev, "Failed to read src\n");
@@ -1142,6 +1194,8 @@ static const struct of_device_id imx_rproc_of_match[] = {
 	{ .compatible = "fsl,imx8mm-cm4", .data = &imx_rproc_cfg_imx8mq },
 	{ .compatible = "fsl,imx8mn-cm7", .data = &imx_rproc_cfg_imx8mn },
 	{ .compatible = "fsl,imx8mp-cm7", .data = &imx_rproc_cfg_imx8mn },
+	{ .compatible = "fsl,imx8mn-cm7-mmio", .data = &imx_rproc_cfg_imx8mn_mmio },
+	{ .compatible = "fsl,imx8mp-cm7-mmio", .data = &imx_rproc_cfg_imx8mn_mmio },
 	{ .compatible = "fsl,imx8qxp-cm4", .data = &imx_rproc_cfg_imx8qxp },
 	{ .compatible = "fsl,imx8qm-cm4", .data = &imx_rproc_cfg_imx8qm },
 	{ .compatible = "fsl,imx8ulp-cm33", .data = &imx_rproc_cfg_imx8ulp },
diff --git a/drivers/remoteproc/imx_rproc.h b/drivers/remoteproc/imx_rproc.h
index 1c7e2127c7584..79a1b8956d142 100644
--- a/drivers/remoteproc/imx_rproc.h
+++ b/drivers/remoteproc/imx_rproc.h
@@ -31,6 +31,8 @@ struct imx_rproc_dcfg {
 	u32				src_mask;
 	u32				src_start;
 	u32				src_stop;
+	u32				gpr_reg;
+	u32				gpr_wait;
 	const struct imx_rproc_att	*att;
 	size_t				att_size;
 	enum imx_rproc_method		method;
-- 
2.40.1