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

From: Thor Thayer
Date: Mon Jul 15 2019 - 14:01:50 EST

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In reply to: Moritz Fischer: "Re: [PATCH 3/3] fpga: altera-cvp: Add Stratix10 (V2) Support"
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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.thayer@xxxxxxxxxxxxxxx wrote:

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>
---
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

Next message: Dmitry Torokhov: "Re: [PATCH v7 1/2] drm/bridge: sil_sii8620: make remote control optional."
Previous message: Linus Torvalds: "Re: drm pull for v5.3-rc1"
In reply to: Moritz Fischer: "Re: [PATCH 3/3] fpga: altera-cvp: Add Stratix10 (V2) Support"
Next in thread: thor . thayer: "[PATCH 1/3] fpga: altera-cvp: Discover Vendor Specific offset"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]