memory: brcmstb: dpfe: introduce DPFE API v3

Introduce code to handle DPFE API v3. We also change the driver to
default to v3 by default and use API v2 only for select chips.
Signed-off-by: Markus Mayer <mmayer@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

drivers/memory/brcmstb_dpfe.c

@@ -76,7 +76,7 @@
 #define DRAM_MR4_TH_OFFS_MASK	0x3
 #define DRAM_MR4_TUF_MASK	0x1
 
-/* DRAM Vendor Offsets & Masks */
+/* DRAM Vendor Offsets & Masks (API v2) */
 #define DRAM_VENDOR_MR5		0x0
 #define DRAM_VENDOR_MR6		0x4
 #define DRAM_VENDOR_MR7		0x8
@@ -85,6 +85,15 @@
 #define DRAM_VENDOR_MASK	0xff
 #define DRAM_VENDOR_SHIFT	24	/* We need to look at byte 3 */
 
+/* DRAM Information Offsets & Masks (API v3) */
+#define DRAM_DDR_INFO_MR4	0x0
+#define DRAM_DDR_INFO_MR5	0x4
+#define DRAM_DDR_INFO_MR6	0x8
+#define DRAM_DDR_INFO_MR7	0xc
+#define DRAM_DDR_INFO_MR8	0x10
+#define DRAM_DDR_INFO_ERROR	0x14
+#define DRAM_DDR_INFO_MASK	0xff
+
 /* Reset register bits & masks */
 #define DCPU_RESET_SHIFT	0x0
 #define DCPU_RESET_MASK		0x1
@@ -121,7 +130,7 @@ enum dpfe_msg_fields {
 	MSG_ARG_COUNT,
 	MSG_ARG0,
 	MSG_CHKSUM,
-	MSG_FIELD_MAX /* Last entry */
+	MSG_FIELD_MAX	= 16 /* Max number of arguments */
 };
 
 enum dpfe_commands {
@@ -196,6 +205,7 @@ static ssize_t show_refresh(struct device *, struct device_attribute *, char *);
 static ssize_t store_refresh(struct device *, struct device_attribute *,
 			  const char *, size_t);
 static ssize_t show_vendor(struct device *, struct device_attribute *, char *);
+static ssize_t show_dram(struct device *, struct device_attribute *, char *);
 
 /*
  * Declare our attributes early, so they can be referenced in the API data
@@ -205,6 +215,7 @@ static ssize_t show_vendor(struct device *, struct device_attribute *, char *);
 static DEVICE_ATTR(dpfe_info, 0444, show_info, NULL);
 static DEVICE_ATTR(dpfe_refresh, 0644, show_refresh, store_refresh);
 static DEVICE_ATTR(dpfe_vendor, 0444, show_vendor, NULL);
+static DEVICE_ATTR(dpfe_dram, 0444, show_dram, NULL);
 
 /* API v2 sysfs attributes */
 static struct attribute *dpfe_v2_attrs[] = {
@@ -215,6 +226,14 @@ static struct attribute *dpfe_v2_attrs[] = {
 };
 ATTRIBUTE_GROUPS(dpfe_v2);
 
+/* API v3 sysfs attributes */
+static struct attribute *dpfe_v3_attrs[] = {
+	&dev_attr_dpfe_info.attr,
+	&dev_attr_dpfe_dram.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(dpfe_v3);
+
 /* API v2 firmware commands */
 static const struct dpfe_api dpfe_api_v2 = {
 	.version = 2,
@@ -245,6 +264,34 @@ static const struct dpfe_api dpfe_api_v2 = {
 	}
 };
 
+/* API v3 firmware commands */
+static const struct dpfe_api dpfe_api_v3 = {
+	.version = 3,
+	.fw_name = NULL, /* We expect the firmware to have been downloaded! */
+	.sysfs_attrs = dpfe_v3_groups,
+	.command = {
+		[DPFE_CMD_GET_INFO] = {
+			[MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
+			[MSG_COMMAND] = 0x0101,
+			[MSG_ARG_COUNT] = 1,
+			[MSG_ARG0] = 1,
+			[MSG_CHKSUM] = 0x104,
+		},
+		[DPFE_CMD_GET_REFRESH] = {
+			[MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
+			[MSG_COMMAND] = 0x0202,
+			[MSG_ARG_COUNT] = 0,
+			/*
+			 * This is a bit ugly. Without arguments, the checksum
+			 * follows right after the argument count and not at
+			 * offset MSG_CHKSUM.
+			 */
+			[MSG_ARG0] = 0x203,
+		},
+		/* There's no GET_VENDOR command in API v3. */
+	},
+};
+
 static bool is_dcpu_enabled(void __iomem *regs)
 {
 	u32 val;
@@ -286,13 +333,13 @@ static void __enable_dcpu(void __iomem *regs)
 	writel_relaxed(val, regs + REG_DCPU_RESET);
 }
 
-static unsigned int get_msg_chksum(const u32 msg[])
+static unsigned int get_msg_chksum(const u32 msg[], unsigned int max)
 {
 	unsigned int sum = 0;
 	unsigned int i;
 
 	/* Don't include the last field in the checksum. */
-	for (i = 0; i < MSG_FIELD_MAX - 1; i++)
+	for (i = 0; i < max; i++)
 		sum += msg[i];
 
 	return sum;
@@ -305,6 +352,11 @@ static void __iomem *get_msg_ptr(struct private_data *priv, u32 response,
 	unsigned int offset;
 	void __iomem *ptr = NULL;
 
+	/* There is no need to use this function for API v3 or later. */
+	if (unlikely(priv->dpfe_api->version >= 3)) {
+		return NULL;
+	}
+
 	msg_type = (response >> DRAM_MSG_TYPE_OFFSET) & DRAM_MSG_TYPE_MASK;
 	offset = (response >> DRAM_MSG_ADDR_OFFSET) & DRAM_MSG_ADDR_MASK;
 
@@ -332,12 +384,25 @@ static void __iomem *get_msg_ptr(struct private_data *priv, u32 response,
 	return ptr;
 }
 
+static void __finalize_command(struct private_data *priv)
+{
+	unsigned int release_mbox;
+
+	/*
+	 * It depends on the API version which MBOX register we have to write to
+	 * to signal we are done.
+	 */
+	release_mbox = (priv->dpfe_api->version < 3)
+			? REG_TO_HOST_MBOX : REG_TO_DCPU_MBOX;
+	writel_relaxed(0, priv->regs + release_mbox);
+}
+
 static int __send_command(struct private_data *priv, unsigned int cmd,
 			  u32 result[])
 {
 	const u32 *msg = priv->dpfe_api->command[cmd];
 	void __iomem *regs = priv->regs;
-	unsigned int i, chksum;
+	unsigned int i, chksum, chksum_idx;
 	int ret = 0;
 	u32 resp;
 
@@ -381,10 +446,11 @@ static int __send_command(struct private_data *priv, unsigned int cmd,
 		/* Read response data */
 		for (i = 0; i < MSG_FIELD_MAX; i++)
 			result[i] = readl_relaxed(regs + DCPU_MSG_RAM(i));
+		chksum_idx = result[MSG_ARG_COUNT] + MSG_ARG_COUNT + 1;
 	}
 
 	/* Tell DCPU we are done */
-	writel_relaxed(0, regs + REG_TO_HOST_MBOX);
+	__finalize_command(priv);
 
 	mutex_unlock(&priv->lock);
 
@@ -392,8 +458,8 @@ static int __send_command(struct private_data *priv, unsigned int cmd,
 		return ret;
 
 	/* Verify response */
-	chksum = get_msg_chksum(result);
-	if (chksum != result[MSG_CHKSUM])
+	chksum = get_msg_chksum(result, chksum_idx);
+	if (chksum != result[chksum_idx])
 		resp = DCPU_RET_ERR_CHKSUM;
 
 	if (resp != DCPU_RET_SUCCESS) {
@@ -710,6 +776,30 @@ static ssize_t show_vendor(struct device *dev, struct device_attribute *devattr,
 	return sprintf(buf, "%#x %#x %#x %#x %#x\n", mr5, mr6, mr7, mr8, err);
 }
 
+static ssize_t show_dram(struct device *dev, struct device_attribute *devattr,
+			 char *buf)
+{
+	u32 response[MSG_FIELD_MAX];
+	struct private_data *priv;
+	ssize_t ret;
+	u32 mr4, mr5, mr6, mr7, mr8, err;
+
+	priv = dev_get_drvdata(dev);
+	ret = generic_show(DPFE_CMD_GET_REFRESH, response, priv, buf);
+	if (ret)
+		return ret;
+
+	mr4 = response[MSG_ARG0 + 0] & DRAM_INFO_MR4_MASK;
+	mr5 = response[MSG_ARG0 + 1] & DRAM_DDR_INFO_MASK;
+	mr6 = response[MSG_ARG0 + 2] & DRAM_DDR_INFO_MASK;
+	mr7 = response[MSG_ARG0 + 3] & DRAM_DDR_INFO_MASK;
+	mr8 = response[MSG_ARG0 + 4] & DRAM_DDR_INFO_MASK;
+	err = response[MSG_ARG0 + 5] & DRAM_DDR_INFO_MASK;
+
+	return sprintf(buf, "%#x %#x %#x %#x %#x %#x\n", mr4, mr5, mr6, mr7,
+			mr8, err);
+}
+
 static int brcmstb_dpfe_resume(struct platform_device *pdev)
 {
 	struct init_data init;
@@ -787,7 +877,13 @@ static int brcmstb_dpfe_remove(struct platform_device *pdev)
 }
 
 static const struct of_device_id brcmstb_dpfe_of_match[] = {
-	{ .compatible = "brcm,dpfe-cpu", .data = &dpfe_api_v2 },
+	/* Use legacy API v2 for a select number of chips */
+	{ .compatible = "brcm,bcm7268-dpfe-cpu", .data = &dpfe_api_v2 },
+	{ .compatible = "brcm,bcm7271-dpfe-cpu", .data = &dpfe_api_v2 },
+	{ .compatible = "brcm,bcm7278-dpfe-cpu", .data = &dpfe_api_v2 },
+	{ .compatible = "brcm,bcm7211-dpfe-cpu", .data = &dpfe_api_v2 },
+	/* API v3 is the default going forward */
+	{ .compatible = "brcm,dpfe-cpu", .data = &dpfe_api_v3 },
 	{}
 };
 MODULE_DEVICE_TABLE(of, brcmstb_dpfe_of_match);