PCI: brcmstb: Check return value of all reset_control_* calls

Always check the return value for invocations of reset_control_xxx() and
propagate the error to the next level.

Although the current functions in reset-brcmstb.c cannot fail, this may
someday change.

Link: https://lore.kernel.org/linux-pci/20240815225731.40276-12-james.quinlan@broadcom.com
Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Stanimir Varbanov <svarbanov@suse.de>

Author: jamesequinlan

drivers/pci/controller/pcie-brcmstb.c

@@ -239,8 +239,8 @@ struct pcie_cfg_data {
 	const enum pcie_type type;
 	const bool has_phy;
 	u8 num_inbound_wins;
-	void (*perst_set)(struct brcm_pcie *pcie, u32 val);
-	void (*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
+	int (*perst_set)(struct brcm_pcie *pcie, u32 val);
+	int (*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
 };
 
 struct subdev_regulators {
@@ -285,8 +285,8 @@ struct brcm_pcie {
 	int			num_memc;
 	u64			memc_size[PCIE_BRCM_MAX_MEMC];
 	u32			hw_rev;
-	void			(*perst_set)(struct brcm_pcie *pcie, u32 val);
-	void			(*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
+	int			(*perst_set)(struct brcm_pcie *pcie, u32 val);
+	int			(*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
 	struct subdev_regulators *sr;
 	bool			ep_wakeup_capable;
 	bool			has_phy;
@@ -749,63 +749,83 @@ static void __iomem *brcm7425_pcie_map_bus(struct pci_bus *bus,
 	return base + DATA_ADDR(pcie);
 }
 
-static void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie, u32 val)
+static int brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie, u32 val)
 {
 	u32 tmp, mask = RGR1_SW_INIT_1_INIT_GENERIC_MASK;
 	u32 shift = RGR1_SW_INIT_1_INIT_GENERIC_SHIFT;
+	int ret = 0;
 
 	if (pcie->bridge_reset) {
 		if (val)
-			reset_control_assert(pcie->bridge_reset);
+			ret = reset_control_assert(pcie->bridge_reset);
 		else
-			reset_control_deassert(pcie->bridge_reset);
+			ret = reset_control_deassert(pcie->bridge_reset);
 
-		return;
+		if (ret)
+			dev_err(pcie->dev, "failed to %s 'bridge' reset, err=%d\n",
+				val ? "assert" : "deassert", ret);
+
+		return ret;
 	}
 
 	tmp = readl(pcie->base + PCIE_RGR1_SW_INIT_1(pcie));
 	tmp = (tmp & ~mask) | ((val << shift) & mask);
 	writel(tmp, pcie->base + PCIE_RGR1_SW_INIT_1(pcie));
+
+	return ret;
 }
 
-static void brcm_pcie_bridge_sw_init_set_7278(struct brcm_pcie *pcie, u32 val)
+static int brcm_pcie_bridge_sw_init_set_7278(struct brcm_pcie *pcie, u32 val)
 {
 	u32 tmp, mask =  RGR1_SW_INIT_1_INIT_7278_MASK;
 	u32 shift = RGR1_SW_INIT_1_INIT_7278_SHIFT;
 
 	tmp = readl(pcie->base + PCIE_RGR1_SW_INIT_1(pcie));
 	tmp = (tmp & ~mask) | ((val << shift) & mask);
 	writel(tmp, pcie->base + PCIE_RGR1_SW_INIT_1(pcie));
+
+	return 0;
 }
 
-static void brcm_pcie_perst_set_4908(struct brcm_pcie *pcie, u32 val)
+static int brcm_pcie_perst_set_4908(struct brcm_pcie *pcie, u32 val)
 {
+	int ret;
+
 	if (WARN_ONCE(!pcie->perst_reset, "missing PERST# reset controller\n"))
-		return;
+		return -EINVAL;
 
 	if (val)
-		reset_control_assert(pcie->perst_reset);
+		ret = reset_control_assert(pcie->perst_reset);
 	else
-		reset_control_deassert(pcie->perst_reset);
+		ret = reset_control_deassert(pcie->perst_reset);
+
+	if (ret)
+		dev_err(pcie->dev, "failed to %s 'perst' reset, err=%d\n",
+			val ? "assert" : "deassert", ret);
+	return ret;
 }
 
-static void brcm_pcie_perst_set_7278(struct brcm_pcie *pcie, u32 val)
+static int brcm_pcie_perst_set_7278(struct brcm_pcie *pcie, u32 val)
 {
 	u32 tmp;
 
 	/* Perst bit has moved and assert value is 0 */
 	tmp = readl(pcie->base + PCIE_MISC_PCIE_CTRL);
 	u32p_replace_bits(&tmp, !val, PCIE_MISC_PCIE_CTRL_PCIE_PERSTB_MASK);
 	writel(tmp, pcie->base +  PCIE_MISC_PCIE_CTRL);
+
+	return 0;
 }
 
-static void brcm_pcie_perst_set_generic(struct brcm_pcie *pcie, u32 val)
+static int brcm_pcie_perst_set_generic(struct brcm_pcie *pcie, u32 val)
 {
 	u32 tmp;
 
 	tmp = readl(pcie->base + PCIE_RGR1_SW_INIT_1(pcie));
 	u32p_replace_bits(&tmp, val, PCIE_RGR1_SW_INIT_1_PERST_MASK);
 	writel(tmp, pcie->base + PCIE_RGR1_SW_INIT_1(pcie));
+
+	return 0;
 }
 
 static void add_inbound_win(struct inbound_win *b, u8 *count, u64 size,
@@ -1020,19 +1040,28 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 	u32 tmp, burst, aspm_support;
 	u8 num_out_wins = 0;
 	int num_inbound_wins = 0;
-	int memc;
+	int memc, ret;
 
 	/* Reset the bridge */
-	pcie->bridge_sw_init_set(pcie, 1);
+	ret = pcie->bridge_sw_init_set(pcie, 1);
+	if (ret)
+		return ret;
 
 	/* Ensure that PERST# is asserted; some bootloaders may deassert it. */
-	if (pcie->type == BCM2711)
-		pcie->perst_set(pcie, 1);
+	if (pcie->type == BCM2711) {
+		ret = pcie->perst_set(pcie, 1);
+		if (ret) {
+			pcie->bridge_sw_init_set(pcie, 0);
+			return ret;
+		}
+	}
 
 	usleep_range(100, 200);
 
 	/* Take the bridge out of reset */
-	pcie->bridge_sw_init_set(pcie, 0);
+	ret = pcie->bridge_sw_init_set(pcie, 0);
+	if (ret)
+		return ret;
 
 	tmp = readl(base + HARD_DEBUG(pcie));
 	if (is_bmips(pcie))
@@ -1251,7 +1280,9 @@ static int brcm_pcie_start_link(struct brcm_pcie *pcie)
 	int ret, i;
 
 	/* Unassert the fundamental reset */
-	pcie->perst_set(pcie, 0);
+	ret = pcie->perst_set(pcie, 0);
+	if (ret)
+		return ret;
 
 	/*
 	 * Wait for 100ms after PERST# deassertion; see PCIe CEM specification
@@ -1443,15 +1474,17 @@ static inline int brcm_phy_stop(struct brcm_pcie *pcie)
 	return pcie->has_phy ? brcm_phy_cntl(pcie, 0) : 0;
 }
 
-static void brcm_pcie_turn_off(struct brcm_pcie *pcie)
+static int brcm_pcie_turn_off(struct brcm_pcie *pcie)
 {
 	void __iomem *base = pcie->base;
-	int tmp;
+	int tmp, ret;
 
 	if (brcm_pcie_link_up(pcie))
 		brcm_pcie_enter_l23(pcie);
 	/* Assert fundamental reset */
-	pcie->perst_set(pcie, 1);
+	ret = pcie->perst_set(pcie, 1);
+	if (ret)
+		return ret;
 
 	/* Deassert request for L23 in case it was asserted */
 	tmp = readl(base + PCIE_MISC_PCIE_CTRL);
@@ -1464,7 +1497,9 @@ static void brcm_pcie_turn_off(struct brcm_pcie *pcie)
 	writel(tmp, base + HARD_DEBUG(pcie));
 
 	/* Shutdown PCIe bridge */
-	pcie->bridge_sw_init_set(pcie, 1);
+	ret = pcie->bridge_sw_init_set(pcie, 1);
+
+	return ret;
 }
 
 static int pci_dev_may_wakeup(struct pci_dev *dev, void *data)
@@ -1482,9 +1517,12 @@ static int brcm_pcie_suspend_noirq(struct device *dev)
 {
 	struct brcm_pcie *pcie = dev_get_drvdata(dev);
 	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
-	int ret;
+	int ret, rret;
+
+	ret = brcm_pcie_turn_off(pcie);
+	if (ret)
+		return ret;
 
-	brcm_pcie_turn_off(pcie);
 	/*
 	 * If brcm_phy_stop() returns an error, just dev_err(). If we
 	 * return the error it will cause the suspend to fail and this is a
@@ -1513,7 +1551,10 @@ static int brcm_pcie_suspend_noirq(struct device *dev)
 						     pcie->sr->supplies);
 			if (ret) {
 				dev_err(dev, "Could not turn off regulators\n");
-				reset_control_reset(pcie->rescal);
+				rret = reset_control_reset(pcie->rescal);
+				if (rret)
+					dev_err(dev, "failed to reset 'rascal' controller ret=%d\n",
+						rret);
 				return ret;
 			}
 		}
@@ -1528,7 +1569,7 @@ static int brcm_pcie_resume_noirq(struct device *dev)
 	struct brcm_pcie *pcie = dev_get_drvdata(dev);
 	void __iomem *base;
 	u32 tmp;
-	int ret;
+	int ret, rret;
 
 	base = pcie->base;
 	ret = clk_prepare_enable(pcie->clk);
@@ -1590,7 +1631,9 @@ static int brcm_pcie_resume_noirq(struct device *dev)
 	if (pcie->sr)
 		regulator_bulk_disable(pcie->sr->num_supplies, pcie->sr->supplies);
 err_reset:
-	reset_control_rearm(pcie->rescal);
+	rret = reset_control_rearm(pcie->rescal);
+	if (rret)
+		dev_err(pcie->dev, "failed to rearm 'rescal' reset, err=%d\n", rret);
 err_disable_clk:
 	clk_disable_unprepare(pcie->clk);
 	return ret;