Hi Moritz,

On 7/14/19 1:55 PM, Moritz Fischer wrote:
Hi Thor,

On Thu, Jul 11, 2019 at 03:32:50PM -0500, thor.tha...@linux.intel.com wrote:
From: Thor Thayer <thor.tha...@linux.intel.com>

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.tha...@linux.intel.com>
---
  drivers/fpga/altera-cvp.c | 173 ++++++++++++++++++++++++++++++++++++++++++----
  1 file changed, 158 insertions(+), 15 deletions(-)

diff --git a/drivers/fpga/altera-cvp.c b/drivers/fpga/altera-cvp.c
index 59835f6f9b2d..21bb08e5f52a 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 +76,26 @@ 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 inline void altera_read_config_byte(struct altera_cvp_conf *conf,
+                                          int where, u8 *val)
+{
+       pci_read_config_byte(conf->pci_dev, conf->vsec_offset + where, val);
+}
+
  static inline void altera_read_config_dword(struct altera_cvp_conf *conf,
                                            int where, u32 *val)
  {
@@ -155,6 +188,57 @@ static inline 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;
+
+       /* Clear the START_XFER and CVP_CONFIG bits */
+       altera_read_config_dword(conf, VSE_CVP_PROG_CTRL, &val);
+       val &= ~VSE_CVP_PROG_CTRL_MASK;
+       altera_write_config_dword(conf, VSE_CVP_PROG_CTRL, val);
+
+       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;
+       u32 count = 0;
+       int ret;
+       u8 val, delta_credit;

Reverse xmas-tree.

OK.

+
+       do {
+               altera_read_config_byte(conf, VSE_CVP_TX_CREDITS, &val);
+               delta_credit = (val - conf->current_credit_byte) & 0xff;

Can 0xff be a named constant?

Hmm. I'll rework this. After looking at this closer, this shouldn't be needed since all the values are u8. I need to handle the rollover but the mask is meaningless.

+
+               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;
+               }
+
+               udelay(1);

A comment why this (1 us) is required would be nice :)

Yes, I'll add a comment. It is to limit the traffic from queries as well as having a consistent timeout.

+       } while (!delta_credit);
+
+       return 0;
+}
+
  static int altera_cvp_send_block(struct altera_cvp_conf *conf,
                                 const u32 *data, size_t len)
  {
@@ -196,10 +280,12 @@ 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");
@@ -261,7 +347,16 @@ 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);
@@ -269,9 +364,10 @@ 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;
@@ -281,7 +377,16 @@ 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);
@@ -289,11 +394,12 @@ 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;
  }
@@ -311,15 +417,26 @@ 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
@@ -370,7 +487,8 @@ 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");
@@ -384,6 +502,24 @@ 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);
@@ -486,6 +622,13 @@ 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->current_credit_byte = 0;
+
        conf->map = pci_iomap(pdev, CVP_BAR, 0);
        if (!conf->map) {
                dev_warn(&pdev->dev, "Mapping CVP BAR failed\n");
--
2.7.4


Thanks,
Moritz


Thank you for reviewing!

Thor

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