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From:   Terry Bowman <terry.bowman@amd.com>
To:     <terry.bowman@amd.com>, <linux@roeck-us.net>,
        <linux-watchdog@vger.kernel.org>, <jdelvare@suse.com>,
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        <Mario.Limonciello@amd.com>
Subject: [PATCH v4 6/9] i2c: piix4: Add EFCH MMIO support to region request and release
Date:   Sun, 30 Jan 2022 12:41:27 -0600
Message-ID: <20220130184130.176646-7-terry.bowman@amd.com>
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EFCH cd6h/cd7h port I/O may no longer be available on later AMD
processors and it is recommended to use MMIO instead. Update the
request and release functions to support MMIO.

MMIO request/release and mmapping require details during cleanup.
Add a MMIO configuration structure containing resource and vaddress
details for mapping the region, accessing the region, and releasing
the region.

Signed-off-by: Terry Bowman <terry.bowman@amd.com>
---
 drivers/i2c/busses/i2c-piix4.c | 61 ++++++++++++++++++++++++++++++----
 1 file changed, 55 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index 32a30af5778a..7defa0c5f1f9 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -98,6 +98,9 @@
 #define SB800_PIIX4_PORT_IDX_MASK_KERNCZ	0x18
 #define SB800_PIIX4_PORT_IDX_SHIFT_KERNCZ	3
 
+#define SB800_PIIX4_FCH_PM_ADDR			0xFED80300
+#define SB800_PIIX4_FCH_PM_SIZE			8
+
 /* insmod parameters */
 
 /* If force is set to anything different from 0, we forcibly enable the
@@ -156,6 +159,12 @@ static const char *piix4_main_port_names_sb800[PIIX4_MAX_ADAPTERS] = {
 };
 static const char *piix4_aux_port_name_sb800 = " port 1";
 
+struct sb800_mmio_cfg {
+	void __iomem *addr;
+	struct resource *res;
+	bool use_mmio;
+};
+
 struct i2c_piix4_adapdata {
 	unsigned short smba;
 
@@ -163,10 +172,40 @@ struct i2c_piix4_adapdata {
 	bool sb800_main;
 	bool notify_imc;
 	u8 port;		/* Port number, shifted */
+	struct sb800_mmio_cfg mmio_cfg;
 };
 
-static int piix4_sb800_region_request(struct device *dev)
+static int piix4_sb800_region_request(struct device *dev,
+				      struct sb800_mmio_cfg *mmio_cfg)
 {
+	if (mmio_cfg->use_mmio) {
+		struct resource *res;
+		void __iomem *addr;
+
+		res = request_mem_region_muxed(SB800_PIIX4_FCH_PM_ADDR,
+					       SB800_PIIX4_FCH_PM_SIZE,
+					       "sb800_piix4_smb");
+		if (!res) {
+			dev_err(dev,
+				"SMBus base address memory region 0x%x already in use.\n",
+				SB800_PIIX4_FCH_PM_ADDR);
+			return -EBUSY;
+		}
+
+		addr = ioremap(SB800_PIIX4_FCH_PM_ADDR,
+			       SB800_PIIX4_FCH_PM_SIZE);
+		if (!addr) {
+			release_resource(res);
+			dev_err(dev, "SMBus base address mapping failed.\n");
+			return -ENOMEM;
+		}
+
+		mmio_cfg->res = res;
+		mmio_cfg->addr = addr;
+
+		return 0;
+	}
+
 	if (!request_muxed_region(SB800_PIIX4_SMB_IDX, SB800_PIIX4_SMB_MAP_SIZE,
 				  "sb800_piix4_smb")) {
 		dev_err(dev,
@@ -178,8 +217,15 @@ static int piix4_sb800_region_request(struct device *dev)
 	return 0;
 }
 
-static void piix4_sb800_region_release(struct device *dev)
+static void piix4_sb800_region_release(struct device *dev,
+				       struct sb800_mmio_cfg *mmio_cfg)
 {
+	if (mmio_cfg->use_mmio) {
+		iounmap(mmio_cfg->addr);
+		release_resource(mmio_cfg->res);
+		return;
+	}
+
 	release_region(SB800_PIIX4_SMB_IDX, SB800_PIIX4_SMB_MAP_SIZE);
 }
 
@@ -288,11 +334,13 @@ static int piix4_setup_sb800_smba(struct pci_dev *PIIX4_dev,
 				  u8 *smb_en_status,
 				  unsigned short *piix4_smba)
 {
+	struct sb800_mmio_cfg mmio_cfg;
 	u8 smba_en_lo;
 	u8 smba_en_hi;
 	int retval;
 
-	retval = piix4_sb800_region_request(&PIIX4_dev->dev);
+	mmio_cfg.use_mmio = 0;
+	retval = piix4_sb800_region_request(&PIIX4_dev->dev, &mmio_cfg);
 	if (retval)
 		return retval;
 
@@ -301,7 +349,7 @@ static int piix4_setup_sb800_smba(struct pci_dev *PIIX4_dev,
 	outb_p(smb_en + 1, SB800_PIIX4_SMB_IDX);
 	smba_en_hi = inb_p(SB800_PIIX4_SMB_IDX + 1);
 
-	piix4_sb800_region_release(&PIIX4_dev->dev);
+	piix4_sb800_region_release(&PIIX4_dev->dev, &mmio_cfg);
 
 	if (!smb_en) {
 		*smb_en_status = smba_en_lo & 0x10;
@@ -731,7 +779,7 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
 	u8 prev_port;
 	int retval;
 
-	retval = piix4_sb800_region_request(&adap->dev);
+	retval = piix4_sb800_region_request(&adap->dev, &adapdata->mmio_cfg);
 	if (retval)
 		return retval;
 
@@ -802,7 +850,7 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
 		piix4_imc_wakeup();
 
 release:
-	piix4_sb800_region_release(&adap->dev);
+	piix4_sb800_region_release(&adap->dev, &adapdata->mmio_cfg);
 	return retval;
 }
 
@@ -880,6 +928,7 @@ static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
 		return -ENOMEM;
 	}
 
+	adapdata->mmio_cfg.use_mmio = 0;
 	adapdata->smba = smba;
 	adapdata->sb800_main = sb800_main;
 	adapdata->port = port << piix4_port_shift_sb800;
-- 
2.30.2