diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-5.4/950-0026-i2c-bcm2835-Add-debug-support.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-5.4/950-0026-i2c-bcm2835-Add-debug-support.patch | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-5.4/950-0026-i2c-bcm2835-Add-debug-support.patch b/target/linux/bcm27xx/patches-5.4/950-0026-i2c-bcm2835-Add-debug-support.patch new file mode 100644 index 0000000000..5208e09b49 --- /dev/null +++ b/target/linux/bcm27xx/patches-5.4/950-0026-i2c-bcm2835-Add-debug-support.patch @@ -0,0 +1,189 @@ +From d4739fb63aa2b47132b66225cef55eb66784df13 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org> +Date: Tue, 1 Nov 2016 15:15:41 +0100 +Subject: [PATCH] i2c: bcm2835: Add debug support +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +This adds a debug module parameter to aid in debugging transfer issues +by printing info to the kernel log. When enabled, status values are +collected in the interrupt routine and msg info in +bcm2835_i2c_start_transfer(). This is done in a way that tries to avoid +affecting timing. Having printk in the isr can mask issues. + +debug values (additive): +1: Print info on error +2: Print info on all transfers +3: Print messages before transfer is started + +The value can be changed at runtime: +/sys/module/i2c_bcm2835/parameters/debug + +Example output, debug=3: +[ 747.114448] bcm2835_i2c_xfer: msg(1/2) write addr=0x54, len=2 flags= [i2c1] +[ 747.114463] bcm2835_i2c_xfer: msg(2/2) read addr=0x54, len=32 flags= [i2c1] +[ 747.117809] start_transfer: msg(1/2) write addr=0x54, len=2 flags= [i2c1] +[ 747.117825] isr: remain=2, status=0x30000055 : TA TXW TXD TXE [i2c1] +[ 747.117839] start_transfer: msg(2/2) read addr=0x54, len=32 flags= [i2c1] +[ 747.117849] isr: remain=32, status=0xd0000039 : TA RXR TXD RXD [i2c1] +[ 747.117861] isr: remain=20, status=0xd0000039 : TA RXR TXD RXD [i2c1] +[ 747.117870] isr: remain=8, status=0x32 : DONE TXD RXD [i2c1] + +Signed-off-by: Noralf Trønnes <noralf@tronnes.org> +--- + drivers/i2c/busses/i2c-bcm2835.c | 99 +++++++++++++++++++++++++++++++- + 1 file changed, 98 insertions(+), 1 deletion(-) + +--- a/drivers/i2c/busses/i2c-bcm2835.c ++++ b/drivers/i2c/busses/i2c-bcm2835.c +@@ -51,6 +51,18 @@ + #define BCM2835_I2C_CDIV_MIN 0x0002 + #define BCM2835_I2C_CDIV_MAX 0xFFFE + ++static unsigned int debug; ++module_param(debug, uint, 0644); ++MODULE_PARM_DESC(debug, "1=err, 2=isr, 3=xfer"); ++ ++#define BCM2835_DEBUG_MAX 512 ++struct bcm2835_debug { ++ struct i2c_msg *msg; ++ int msg_idx; ++ size_t remain; ++ u32 status; ++}; ++ + struct bcm2835_i2c_dev { + struct device *dev; + void __iomem *regs; +@@ -63,8 +75,78 @@ struct bcm2835_i2c_dev { + u32 msg_err; + u8 *msg_buf; + size_t msg_buf_remaining; ++ struct bcm2835_debug debug[BCM2835_DEBUG_MAX]; ++ unsigned int debug_num; ++ unsigned int debug_num_msgs; + }; + ++static inline void bcm2835_debug_add(struct bcm2835_i2c_dev *i2c_dev, u32 s) ++{ ++ if (!i2c_dev->debug_num_msgs || i2c_dev->debug_num >= BCM2835_DEBUG_MAX) ++ return; ++ ++ i2c_dev->debug[i2c_dev->debug_num].msg = i2c_dev->curr_msg; ++ i2c_dev->debug[i2c_dev->debug_num].msg_idx = ++ i2c_dev->debug_num_msgs - i2c_dev->num_msgs; ++ i2c_dev->debug[i2c_dev->debug_num].remain = i2c_dev->msg_buf_remaining; ++ i2c_dev->debug[i2c_dev->debug_num].status = s; ++ i2c_dev->debug_num++; ++} ++ ++static void bcm2835_debug_print_status(struct bcm2835_i2c_dev *i2c_dev, ++ struct bcm2835_debug *d) ++{ ++ u32 s = d->status; ++ ++ pr_info("isr: remain=%zu, status=0x%x : %s%s%s%s%s%s%s%s%s%s [i2c%d]\n", ++ d->remain, s, ++ s & BCM2835_I2C_S_TA ? "TA " : "", ++ s & BCM2835_I2C_S_DONE ? "DONE " : "", ++ s & BCM2835_I2C_S_TXW ? "TXW " : "", ++ s & BCM2835_I2C_S_RXR ? "RXR " : "", ++ s & BCM2835_I2C_S_TXD ? "TXD " : "", ++ s & BCM2835_I2C_S_RXD ? "RXD " : "", ++ s & BCM2835_I2C_S_TXE ? "TXE " : "", ++ s & BCM2835_I2C_S_RXF ? "RXF " : "", ++ s & BCM2835_I2C_S_ERR ? "ERR " : "", ++ s & BCM2835_I2C_S_CLKT ? "CLKT " : "", ++ i2c_dev->adapter.nr); ++} ++ ++static void bcm2835_debug_print_msg(struct bcm2835_i2c_dev *i2c_dev, ++ struct i2c_msg *msg, int i, int total, ++ const char *fname) ++{ ++ pr_info("%s: msg(%d/%d) %s addr=0x%02x, len=%u flags=%s%s%s%s%s%s%s [i2c%d]\n", ++ fname, i, total, ++ msg->flags & I2C_M_RD ? "read" : "write", msg->addr, msg->len, ++ msg->flags & I2C_M_TEN ? "TEN" : "", ++ msg->flags & I2C_M_RECV_LEN ? "RECV_LEN" : "", ++ msg->flags & I2C_M_NO_RD_ACK ? "NO_RD_ACK" : "", ++ msg->flags & I2C_M_IGNORE_NAK ? "IGNORE_NAK" : "", ++ msg->flags & I2C_M_REV_DIR_ADDR ? "REV_DIR_ADDR" : "", ++ msg->flags & I2C_M_NOSTART ? "NOSTART" : "", ++ msg->flags & I2C_M_STOP ? "STOP" : "", ++ i2c_dev->adapter.nr); ++} ++ ++static void bcm2835_debug_print(struct bcm2835_i2c_dev *i2c_dev) ++{ ++ struct bcm2835_debug *d; ++ unsigned int i; ++ ++ for (i = 0; i < i2c_dev->debug_num; i++) { ++ d = &i2c_dev->debug[i]; ++ if (d->status == ~0) ++ bcm2835_debug_print_msg(i2c_dev, d->msg, d->msg_idx, ++ i2c_dev->debug_num_msgs, "start_transfer"); ++ else ++ bcm2835_debug_print_status(i2c_dev, d); ++ } ++ if (i2c_dev->debug_num >= BCM2835_DEBUG_MAX) ++ pr_info("BCM2835_DEBUG_MAX reached\n"); ++} ++ + static inline void bcm2835_i2c_writel(struct bcm2835_i2c_dev *i2c_dev, + u32 reg, u32 val) + { +@@ -252,6 +334,7 @@ static void bcm2835_i2c_start_transfer(s + bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_A, msg->addr); + bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_DLEN, msg->len); + bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, c); ++ bcm2835_debug_add(i2c_dev, ~0); + } + + static void bcm2835_i2c_finish_transfer(struct bcm2835_i2c_dev *i2c_dev) +@@ -278,6 +361,7 @@ static irqreturn_t bcm2835_i2c_isr(int t + u32 val, err; + + val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S); ++ bcm2835_debug_add(i2c_dev, val); + + err = val & (BCM2835_I2C_S_CLKT | BCM2835_I2C_S_ERR); + if (err) { +@@ -344,6 +428,13 @@ static int bcm2835_i2c_xfer(struct i2c_a + unsigned long time_left; + int i; + ++ if (debug) ++ i2c_dev->debug_num_msgs = num; ++ ++ if (debug > 2) ++ for (i = 0; i < num; i++) ++ bcm2835_debug_print_msg(i2c_dev, &msgs[i], i + 1, num, __func__); ++ + for (i = 0; i < (num - 1); i++) + if (msgs[i].flags & I2C_M_RD) { + dev_warn_once(i2c_dev->dev, +@@ -362,6 +453,10 @@ static int bcm2835_i2c_xfer(struct i2c_a + + bcm2835_i2c_finish_transfer(i2c_dev); + ++ if (debug > 1 || (debug && (!time_left || i2c_dev->msg_err))) ++ bcm2835_debug_print(i2c_dev); ++ i2c_dev->debug_num_msgs = 0; ++ i2c_dev->debug_num = 0; + if (!time_left) { + bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, + BCM2835_I2C_C_CLEAR); +@@ -372,7 +467,9 @@ static int bcm2835_i2c_xfer(struct i2c_a + if (!i2c_dev->msg_err) + return num; + +- dev_dbg(i2c_dev->dev, "i2c transfer failed: %x\n", i2c_dev->msg_err); ++ if (debug) ++ dev_err(i2c_dev->dev, "i2c transfer failed: %x\n", ++ i2c_dev->msg_err); + + if (i2c_dev->msg_err & BCM2835_I2C_S_ERR) + return -EREMOTEIO; |