[PATCH v2 1/2] ipmi: kcs_bmc_aspeed: g6: Add KCS Channel 4 over PCIe

[Grégoire Layet]

Created a 5th KCS channel to match against the KCS 4 over PCIe addresses.

The ASPEED AST2600 has a PCIe to LPC controller. It includes a KCS
interface on channel 4. This is a fully KCS-compatible interface
that is exposed over PCIe.

The 5th channel created is only valid on the AST2600.
This cannot be used for AST2400 and AST2500 chips, as they don't have LPC
over PCIE.

Signed-off-by: Grégoire Layet <gregoire.layet@xxxxxxxxxxxxx>
---
 drivers/char/ipmi/kcs_bmc_aspeed.c | 39 ++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/drivers/char/ipmi/kcs_bmc_aspeed.c b/drivers/char/ipmi/kcs_bmc_aspeed.c
index a13a3470c17a..4d93af2455b8 100644
--- a/drivers/char/ipmi/kcs_bmc_aspeed.c
+++ b/drivers/char/ipmi/kcs_bmc_aspeed.c
@@ -26,7 +26,7 @@
 
 #define DEVICE_NAME     "ast-kcs-bmc"
 
-#define KCS_CHANNEL_MAX     4
+#define KCS_CHANNEL_MAX     5
 
 /*
  * Field class descriptions
@@ -102,6 +102,12 @@
 #define     LPC_LSADR12_LSADR2_SHIFT 16
 #define     LPC_LSADR12_LSADR1_MASK  GENMASK(15, 0)
 #define     LPC_LSADR12_LSADR1_SHIFT 0
+#define PCIE_LPC_HICRB       0x900
+#define PCIE_LPC_HICRC       0x904
+#define PCIE_LPC_LADR4       0x910
+#define PCIE_LPC_IDR4        0x914
+#define PCIE_LPC_ODR4        0x918
+#define PCIE_LPC_STR4        0x91C
 
 #define OBE_POLL_PERIOD	     (HZ / 2)
 
@@ -191,6 +197,9 @@ static void aspeed_kcs_outb(struct kcs_bmc_device *kcs_bmc, u32 reg, u8 data)
 	case 4:
 		regmap_update_bits(priv->map, LPC_HICRC, LPC_HICRC_IRQXE4, LPC_HICRC_IRQXE4);
 		break;
+	case 5:
+		regmap_update_bits(priv->map, PCIE_LPC_HICRC, LPC_HICRC_IRQXE4, LPC_HICRC_IRQXE4);
+		break;
 	default:
 		break;
 	}
@@ -278,6 +287,14 @@ static int aspeed_kcs_set_address(struct kcs_bmc_device *kcs_bmc, u32 addrs[2],
 
 		break;
 
+	case 5:
+		if (nr_addrs == 1)
+			regmap_write(priv->map, PCIE_LPC_LADR4, ((addrs[0] + 1) << 16) | addrs[0]);
+		else
+			regmap_write(priv->map, PCIE_LPC_LADR4, (addrs[1] << 16) | addrs[0]);
+
+		break;
+
 	default:
 		return -EINVAL;
 	}
@@ -344,6 +361,11 @@ static int aspeed_kcs_config_upstream_irq(struct aspeed_kcs_bmc *priv, u32 id, u
 		val = (id << LPC_HICRC_ID4IRQX_SHIFT) | (hw_type << LPC_HICRC_TY4IRQX_SHIFT);
 		regmap_update_bits(priv->map, LPC_HICRC, mask, val);
 		break;
+	case 5:
+		mask = LPC_HICRC_ID4IRQX_MASK | LPC_HICRC_TY4IRQX_MASK | LPC_HICRC_OBF4_AUTO_CLR;
+		val = (id << LPC_HICRC_ID4IRQX_SHIFT) | (hw_type << LPC_HICRC_TY4IRQX_SHIFT);
+		regmap_update_bits(priv->map, PCIE_LPC_HICRC, mask, val);
+		break;
 	default:
 		dev_warn(priv->kcs_bmc.dev,
 			 "SerIRQ configuration not supported on KCS channel %d\n",
@@ -373,6 +395,9 @@ static void aspeed_kcs_enable_channel(struct kcs_bmc_device *kcs_bmc, bool enabl
 	case 4:
 		regmap_update_bits(priv->map, LPC_HICRB, LPC_HICRB_LPC4E, enable * LPC_HICRB_LPC4E);
 		return;
+	case 5:
+		regmap_update_bits(priv->map, PCIE_LPC_HICRB, LPC_HICRB_LPC4E, enable * LPC_HICRB_LPC4E);
+		return;
 	default:
 		pr_warn("%s: Unsupported channel: %d", __func__, kcs_bmc->channel);
 		return;
@@ -452,6 +477,10 @@ static void aspeed_kcs_irq_mask_update(struct kcs_bmc_device *kcs_bmc, u8 mask,
 			regmap_update_bits(priv->map, LPC_HICRB, LPC_HICRB_IBFIE4,
 					   enable * LPC_HICRB_IBFIE4);
 			return;
+		case 5:
+			regmap_update_bits(priv->map, PCIE_LPC_HICRB, LPC_HICRB_IBFIE4,
+					   enable * LPC_HICRB_IBFIE4);
+			return;
 		default:
 			pr_warn("%s: Unsupported channel: %d", __func__, kcs_bmc->channel);
 			return;
@@ -492,6 +521,7 @@ static const struct kcs_ioreg ast_kcs_bmc_ioregs[KCS_CHANNEL_MAX] = {
 	{ .idr = LPC_IDR2, .odr = LPC_ODR2, .str = LPC_STR2 },
 	{ .idr = LPC_IDR3, .odr = LPC_ODR3, .str = LPC_STR3 },
 	{ .idr = LPC_IDR4, .odr = LPC_ODR4, .str = LPC_STR4 },
+	{ .idr = PCIE_LPC_IDR4, .odr = PCIE_LPC_ODR4, .str = PCIE_LPC_STR4 },
 };
 
 static int aspeed_kcs_of_get_channel(struct platform_device *pdev)
@@ -575,11 +605,16 @@ static int aspeed_kcs_probe(struct platform_device *pdev)
 	if (channel < 0)
 		return channel;
 
+	np = pdev->dev.of_node;
+	if (channel == 5 && !of_device_is_compatible(np, "aspeed,ast2600-kcs-bmc")) {
+		dev_err(&pdev->dev, "LPC over PCIE KCS4 only supported on ast2600\n");
+		return -ENODEV;
+	}
+
 	nr_addrs = aspeed_kcs_of_get_io_address(pdev, addrs);
 	if (nr_addrs < 0)
 		return nr_addrs;
 
-	np = pdev->dev.of_node;
 	rc = of_property_read_u32_array(np, "aspeed,lpc-interrupts", upstream_irq, 2);
 	if (rc && rc != -EINVAL)
 		return -EINVAL;
-- 
2.54.0