[PATCHv3 3/3] fpga: altera-cvp: Add Stratix10 (V2) Support

[thor . thayer]

From: Thor Thayer <thor.thayer@xxxxxxxxxxxxxxx>

Add Stratix10 specific functions that use a credit mechanism
to throttle data to the CvP FIFOs. Add a private structure
with function pointers for V1 vs V2 functions.

Signed-off-by: Thor Thayer <thor.thayer@xxxxxxxxxxxxxxx>
---
v2 Remove inline function declaration
   Reverse Christmas Tree format for local variables
   Remove mask from credit calculation
   Add commment for the delay(1) function in wait_for_credit()
v3 Fix return code of abstraction function
   Move reset of current_credit_byte to clear_state().
   Check return code of credit register read in wait_for_credit()
   Check return code of clear_state read/write register.
---
 drivers/fpga/altera-cvp.c | 193 ++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 178 insertions(+), 15 deletions(-)

diff --git a/drivers/fpga/altera-cvp.c b/drivers/fpga/altera-cvp.c
index b08c0fd353ba..6bf7462af4f3 100644
--- a/drivers/fpga/altera-cvp.c
+++ b/drivers/fpga/altera-cvp.c
@@ -43,16 +43,32 @@
 #define VSE_CVP_PROG_CTRL		0x2c	/* 32bit */
 #define VSE_CVP_PROG_CTRL_CONFIG	BIT(0)
 #define VSE_CVP_PROG_CTRL_START_XFER	BIT(1)
+#define VSE_CVP_PROG_CTRL_MASK		GENMASK(1, 0)
 
 #define VSE_UNCOR_ERR_STATUS		0x34	/* 32bit */
 #define VSE_UNCOR_ERR_CVP_CFG_ERR	BIT(5)	/* CVP_CONFIG_ERROR_LATCHED */
 
+/* V2 Defines */
+#define VSE_CVP_TX_CREDITS		0x49	/* 8bit */
+
+#define CREDIT_TIMEOUT_US		20000
+#define V2_POLL_TIMEOUT_US		1000000
+#define V2_USER_TIMEOUT_US		500000
+
+#define V1_POLL_TIMEOUT_US		10
+
 #define DRV_NAME		"altera-cvp"
 #define ALTERA_CVP_MGR_NAME	"Altera CvP FPGA Manager"
 
+/* Write block sizes */
+#define ALTERA_CVP_V1_SIZE	4
+#define ALTERA_CVP_V2_SIZE	4096
+
 /* Optional CvP config error status check for debugging */
 static bool altera_cvp_chkcfg;
 
+struct cvp_priv;
+
 struct altera_cvp_conf {
 	struct fpga_manager	*mgr;
 	struct pci_dev		*pci_dev;
@@ -60,9 +76,27 @@ struct altera_cvp_conf {
 	void			(*write_data)(struct altera_cvp_conf *, u32);
 	char			mgr_name[64];
 	u8			numclks;
+	u8			current_credit_byte;
 	u32			vsec_offset;
+	const struct cvp_priv	*priv;
 };
 
+struct cvp_priv {
+	void	(*switch_clk)(struct altera_cvp_conf *conf);
+	int	(*clear_state)(struct altera_cvp_conf *conf);
+	int	(*wait_credit)(struct fpga_manager *mgr, u32 blocks);
+	int	block_size;
+	int	poll_time_us;
+	int	user_time_us;
+};
+
+static int altera_read_config_byte(struct altera_cvp_conf *conf,
+				   int where, u8 *val)
+{
+	return pci_read_config_byte(conf->pci_dev, conf->vsec_offset + where,
+				    val);
+}
+
 static int altera_read_config_dword(struct altera_cvp_conf *conf,
 				    int where, u32 *val)
 {
@@ -158,6 +192,78 @@ static int altera_cvp_chk_error(struct fpga_manager *mgr, size_t bytes)
 	return 0;
 }
 
+/*
+ * CvP Version2 Functions
+ * Recent Intel FPGAs use a credit mechanism to throttle incoming
+ * bitstreams and a different method of clearing the state.
+ */
+
+static int altera_cvp_v2_clear_state(struct altera_cvp_conf *conf)
+{
+	u32 val;
+	int ret;
+
+	conf->current_credit_byte = 0;
+
+	/* Clear the START_XFER and CVP_CONFIG bits */
+	ret = altera_read_config_dword(conf, VSE_CVP_PROG_CTRL, &val);
+	if (ret) {
+		dev_err(&conf->pci_dev->dev,
+			"Error reading CVP Program Control Register\n");
+		return ret;
+	}
+
+	val &= ~VSE_CVP_PROG_CTRL_MASK;
+	ret = altera_write_config_dword(conf, VSE_CVP_PROG_CTRL, val);
+	if (ret) {
+		dev_err(&conf->pci_dev->dev,
+			"Error writing CVP Program Control Register\n");
+		return ret;
+	}
+
+	return altera_cvp_wait_status(conf, VSE_CVP_STATUS_CFG_RDY, 0,
+				      conf->priv->poll_time_us);
+}
+
+static int altera_cvp_v2_wait_for_credit(struct fpga_manager *mgr,
+					 u32 blocks)
+{
+	struct altera_cvp_conf *conf = mgr->priv;
+	u8 val, delta_credit;
+	u32 count = 0;
+	int ret;
+
+	do {
+		ret = altera_read_config_byte(conf, VSE_CVP_TX_CREDITS, &val);
+		if (ret) {
+			dev_err(&conf->pci_dev->dev,
+				"Error reading CVP Credit Register\n");
+			return ret;
+		}
+
+		delta_credit = val - conf->current_credit_byte;
+
+		ret = altera_cvp_chk_error(mgr, blocks * ALTERA_CVP_V2_SIZE);
+		if (ret) {
+			dev_err(&conf->pci_dev->dev,
+				"CE Bit error credits host[0x%x]:dev[0x%x]\n",
+				conf->current_credit_byte, val);
+			return -EAGAIN;
+		}
+
+		if (count++ >= CREDIT_TIMEOUT_US) {
+			dev_err(&conf->pci_dev->dev,
+				"Timeout waiting for credit\n");
+			return -ETIMEDOUT;
+		}
+
+		/* Limit the traffic & ensure a timeout in usec */
+		udelay(1);
+	} while (!delta_credit);
+
+	return 0;
+}
+
 static int altera_cvp_send_block(struct altera_cvp_conf *conf,
 				 const u32 *data, size_t len)
 {
@@ -199,10 +305,12 @@ static int altera_cvp_teardown(struct fpga_manager *mgr,
 	 * - set CVP_NUMCLKS to 1 and then issue CVP_DUMMY_WR dummy
 	 *   writes to the HIP
 	 */
-	altera_cvp_dummy_write(conf); /* from CVP clock to internal clock */
+	if (conf->priv->switch_clk)
+		conf->priv->switch_clk(conf);
 
 	/* STEP 15 - poll CVP_CONFIG_READY bit for 0 with 10us timeout */
-	ret = altera_cvp_wait_status(conf, VSE_CVP_STATUS_CFG_RDY, 0, 10);
+	ret = altera_cvp_wait_status(conf, VSE_CVP_STATUS_CFG_RDY, 0,
+				     conf->priv->poll_time_us);
 	if (ret)
 		dev_err(&mgr->dev, "CFG_RDY == 0 timeout\n");
 
@@ -264,7 +372,16 @@ static int altera_cvp_write_init(struct fpga_manager *mgr,
 	 * STEP 3
 	 * - set CVP_NUMCLKS to 1 and issue CVP_DUMMY_WR dummy writes to the HIP
 	 */
-	altera_cvp_dummy_write(conf);
+	if (conf->priv->switch_clk)
+		conf->priv->switch_clk(conf);
+
+	if (conf->priv->clear_state) {
+		ret = conf->priv->clear_state(conf);
+		if (ret) {
+			dev_err(&mgr->dev, "Problem clearing out state\n");
+			return ret;
+		}
+	}
 
 	/* STEP 4 - set CVP_CONFIG bit */
 	altera_read_config_dword(conf, VSE_CVP_PROG_CTRL, &val);
@@ -272,9 +389,10 @@ static int altera_cvp_write_init(struct fpga_manager *mgr,
 	val |= VSE_CVP_PROG_CTRL_CONFIG;
 	altera_write_config_dword(conf, VSE_CVP_PROG_CTRL, val);
 
-	/* STEP 5 - poll CVP_CONFIG READY for 1 with 10us timeout */
+	/* STEP 5 - poll CVP_CONFIG READY for 1 with timeout */
 	ret = altera_cvp_wait_status(conf, VSE_CVP_STATUS_CFG_RDY,
-				     VSE_CVP_STATUS_CFG_RDY, 10);
+				     VSE_CVP_STATUS_CFG_RDY,
+				     conf->priv->poll_time_us);
 	if (ret) {
 		dev_warn(&mgr->dev, "CFG_RDY == 1 timeout\n");
 		return ret;
@@ -284,7 +402,16 @@ static int altera_cvp_write_init(struct fpga_manager *mgr,
 	 * STEP 6
 	 * - set CVP_NUMCLKS to 1 and issue CVP_DUMMY_WR dummy writes to the HIP
 	 */
-	altera_cvp_dummy_write(conf);
+	if (conf->priv->switch_clk)
+		conf->priv->switch_clk(conf);
+
+	if (altera_cvp_chkcfg) {
+		ret = altera_cvp_chk_error(mgr, 0);
+		if (ret) {
+			dev_warn(&mgr->dev, "CFG_RDY == 1 timeout\n");
+			return ret;
+		}
+	}
 
 	/* STEP 7 - set START_XFER */
 	altera_read_config_dword(conf, VSE_CVP_PROG_CTRL, &val);
@@ -292,11 +419,12 @@ static int altera_cvp_write_init(struct fpga_manager *mgr,
 	altera_write_config_dword(conf, VSE_CVP_PROG_CTRL, val);
 
 	/* STEP 8 - start transfer (set CVP_NUMCLKS for bitstream) */
-	altera_read_config_dword(conf, VSE_CVP_MODE_CTRL, &val);
-	val &= ~VSE_CVP_MODE_CTRL_NUMCLKS_MASK;
-	val |= conf->numclks << VSE_CVP_MODE_CTRL_NUMCLKS_OFF;
-	altera_write_config_dword(conf, VSE_CVP_MODE_CTRL, val);
-
+	if (conf->priv->switch_clk) {
+		altera_read_config_dword(conf, VSE_CVP_MODE_CTRL, &val);
+		val &= ~VSE_CVP_MODE_CTRL_NUMCLKS_MASK;
+		val |= conf->numclks << VSE_CVP_MODE_CTRL_NUMCLKS_OFF;
+		altera_write_config_dword(conf, VSE_CVP_MODE_CTRL, val);
+	}
 	return 0;
 }
 
@@ -314,15 +442,26 @@ static int altera_cvp_write(struct fpga_manager *mgr, const char *buf,
 	done = 0;
 
 	while (remaining) {
-		if (remaining >= sizeof(u32))
-			len = sizeof(u32);
+		/* Use credit throttling if available */
+		if (conf->priv->wait_credit) {
+			status = conf->priv->wait_credit(mgr, done);
+			if (status) {
+				dev_err(&conf->pci_dev->dev,
+					"Wait Credit ERR: 0x%x\n", status);
+				return status;
+			}
+		}
+
+		if (remaining >= conf->priv->block_size)
+			len = conf->priv->block_size;
 		else
 			len = remaining;
 
 		altera_cvp_send_block(conf, data, len);
-		data++;
+		data += len / sizeof(u32);
 		done += len;
 		remaining -= len;
+		conf->current_credit_byte++;
 
 		/*
 		 * STEP 10 (optional) and STEP 11
@@ -372,7 +511,8 @@ static int altera_cvp_write_complete(struct fpga_manager *mgr,
 
 	/* STEP 18 - poll PLD_CLK_IN_USE and USER_MODE bits */
 	mask = VSE_CVP_STATUS_PLD_CLK_IN_USE | VSE_CVP_STATUS_USERMODE;
-	ret = altera_cvp_wait_status(conf, mask, mask, TIMEOUT_US);
+	ret = altera_cvp_wait_status(conf, mask, mask,
+				     conf->priv->user_time_us);
 	if (ret)
 		dev_err(&mgr->dev, "PLD_CLK_IN_USE|USERMODE timeout\n");
 
@@ -386,6 +526,24 @@ static const struct fpga_manager_ops altera_cvp_ops = {
 	.write_complete	= altera_cvp_write_complete,
 };
 
+static const struct cvp_priv cvp_priv_v1 = {
+	.switch_clk	= altera_cvp_dummy_write,
+	.clear_state	= NULL,
+	.wait_credit	= NULL,
+	.block_size	= ALTERA_CVP_V1_SIZE,
+	.poll_time_us	= V1_POLL_TIMEOUT_US,
+	.user_time_us	= TIMEOUT_US,
+};
+
+static const struct cvp_priv cvp_priv_v2 = {
+	.switch_clk	= NULL,
+	.clear_state	= altera_cvp_v2_clear_state,
+	.wait_credit	= altera_cvp_v2_wait_for_credit,
+	.block_size	= ALTERA_CVP_V2_SIZE,
+	.poll_time_us	= V2_POLL_TIMEOUT_US,
+	.user_time_us	= V2_USER_TIMEOUT_US,
+};
+
 static ssize_t chkcfg_show(struct device_driver *dev, char *buf)
 {
 	return snprintf(buf, 3, "%d\n", altera_cvp_chkcfg);
@@ -488,6 +646,11 @@ static int altera_cvp_probe(struct pci_dev *pdev,
 	conf->pci_dev = pdev;
 	conf->write_data = altera_cvp_write_data_iomem;
 
+	if (conf->vsec_offset == 0x200)
+		conf->priv = &cvp_priv_v1;
+	else
+		conf->priv = &cvp_priv_v2;
+
 	conf->map = pci_iomap(pdev, CVP_BAR, 0);
 	if (!conf->map) {
 		dev_warn(&pdev->dev, "Mapping CVP BAR failed\n");
-- 
2.7.4