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Date: Fri, 21 Oct 2022 15:28:32 +0530
From: Vivek Yadav <vivek.2311@...sung.com>
To: rcsekar@...sung.com, wg@...ndegger.com, mkl@...gutronix.de,
davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
pabeni@...hat.com, pankaj.dubey@...sung.com,
ravi.patel@...sung.com, alim.akhtar@...sung.com
Cc: linux-can@...r.kernel.org, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, Vivek Yadav <vivek.2311@...sung.com>
Subject: [PATCH 6/7] can: m_can: Add ECC functionality for message RAM
Whenever MCAN Buffers and FIFOs are stored on message ram, there are
inherent risks of corruption known as single-bit errors.
Enable error correction code (ECC) data intigrity check for Message RAM
to create valid ECC checksums.
ECC uses a respective number of bits, which are added to each word as a
parity and that will raise the error signal on the corruption in the
Interrupt Register(IR).
Message RAM bit error controlled by input signal m_can_aeim_berr[0],
generated by an optional external parity / ECC logic attached to the
Message RAM.
This indicates either Bit Error detected and Corrected(BEC) or No bit
error detected when reading from Message RAM.
Signed-off-by: Vivek Yadav <vivek.2311@...sung.com>
---
drivers/net/can/m_can/m_can.c | 73 +++++++++++++++++++++++++++++++++++
drivers/net/can/m_can/m_can.h | 24 ++++++++++++
2 files changed, 97 insertions(+)
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index dcb582563d5e..578146707d5b 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1535,9 +1535,62 @@ static void m_can_stop(struct net_device *dev)
cdev->can.state = CAN_STATE_STOPPED;
}
+int m_can_config_mram_ecc_check(struct m_can_classdev *cdev, int enable,
+ struct device_node *np)
+{
+ int val = 0;
+ int offset = 0, ret = 0;
+ int delay_count = MRAM_INIT_TIMEOUT;
+ struct m_can_mraminit *mraminit = &cdev->mraminit_sys;
+
+ mraminit->syscon = syscon_regmap_lookup_by_phandle(np,
+ "mram-ecc-cfg");
+ if (IS_ERR(mraminit->syscon)) {
+ /* can fail with -EPROBE_DEFER */
+ ret = PTR_ERR(mraminit->syscon);
+ return ret;
+ }
+
+ if (of_property_read_u32_index(np, "mram-ecc-cfg", 1,
+ &mraminit->reg)) {
+ dev_err(cdev->dev, "couldn't get the mraminit reg. offset!\n");
+ return -ENODEV;
+ }
+
+ val = ((MRAM_ECC_ENABLE_MASK | MRAM_CFG_VALID_MASK |
+ MRAM_INIT_ENABLE_MASK) << offset);
+ regmap_clear_bits(mraminit->syscon, mraminit->reg, val);
+
+ if (enable) {
+ val = (MRAM_ECC_ENABLE_MASK | MRAM_INIT_ENABLE_MASK) << offset;
+ regmap_set_bits(mraminit->syscon, mraminit->reg, val);
+ }
+
+ /* after enable or disable valid flag need to be set*/
+ val = (MRAM_CFG_VALID_MASK << offset);
+ regmap_set_bits(mraminit->syscon, mraminit->reg, val);
+
+ if (enable) {
+ do {
+ regmap_read(mraminit->syscon, mraminit->reg, &val);
+
+ if (val & (MRAM_INIT_DONE_MASK << offset))
+ return 0;
+
+ udelay(1);
+ } while (delay_count--);
+
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
static int m_can_close(struct net_device *dev)
{
struct m_can_classdev *cdev = netdev_priv(dev);
+ struct device_node *np;
+ int err = 0;
netif_stop_queue(dev);
@@ -1557,6 +1610,15 @@ static int m_can_close(struct net_device *dev)
if (cdev->is_peripheral)
can_rx_offload_disable(&cdev->offload);
+ np = cdev->dev->of_node;
+
+ if (np && of_property_read_bool(np, "mram-ecc-cfg")) {
+ err = m_can_config_mram_ecc_check(cdev, ECC_DISABLE, np);
+ if (err < 0)
+ netdev_err(dev,
+ "Message RAM ECC disable config failed\n");
+ }
+
close_candev(dev);
phy_power_off(cdev->transceiver);
@@ -1754,6 +1816,7 @@ static int m_can_open(struct net_device *dev)
{
struct m_can_classdev *cdev = netdev_priv(dev);
int err;
+ struct device_node *np;
err = phy_power_on(cdev->transceiver);
if (err)
@@ -1798,6 +1861,16 @@ static int m_can_open(struct net_device *dev)
goto exit_irq_fail;
}
+ np = cdev->dev->of_node;
+
+ if (np && of_property_read_bool(np, "mram-ecc-cfg")) {
+ err = m_can_config_mram_ecc_check(cdev, ECC_ENABLE, np);
+ if (err < 0) {
+ netdev_err(dev,
+ "Message RAM ECC enable config failed\n");
+ }
+ }
+
/* start the m_can controller */
m_can_start(dev);
diff --git a/drivers/net/can/m_can/m_can.h b/drivers/net/can/m_can/m_can.h
index 4c0267f9f297..3cbfdc64a7db 100644
--- a/drivers/net/can/m_can/m_can.h
+++ b/drivers/net/can/m_can/m_can.h
@@ -28,6 +28,8 @@
#include <linux/can/dev.h>
#include <linux/pinctrl/consumer.h>
#include <linux/phy/phy.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
/* m_can lec values */
enum m_can_lec_type {
@@ -52,12 +54,33 @@ enum m_can_mram_cfg {
MRAM_CFG_NUM,
};
+enum m_can_ecc_cfg {
+ ECC_DISABLE = 0,
+ ECC_ENABLE,
+};
+
/* address offset and element number for each FIFO/Buffer in the Message RAM */
struct mram_cfg {
u16 off;
u8 num;
};
+/* MRAM_INIT_BITS */
+#define MRAM_CFG_VALID_SHIFT 5
+#define MRAM_CFG_VALID_MASK BIT(MRAM_CFG_VALID_SHIFT)
+#define MRAM_ECC_ENABLE_SHIFT 3
+#define MRAM_ECC_ENABLE_MASK BIT(MRAM_ECC_ENABLE_SHIFT)
+#define MRAM_INIT_ENABLE_SHIFT 1
+#define MRAM_INIT_ENABLE_MASK BIT(MRAM_INIT_ENABLE_SHIFT)
+#define MRAM_INIT_DONE_SHIFT 0
+#define MRAM_INIT_DONE_MASK BIT(MRAM_INIT_DONE_SHIFT)
+#define MRAM_INIT_TIMEOUT 50
+
+struct m_can_mraminit {
+ struct regmap *syscon; /* for mraminit ctrl. reg. access */
+ unsigned int reg; /* register index within syscon */
+};
+
struct m_can_classdev;
struct m_can_ops {
/* Device specific call backs */
@@ -92,6 +115,7 @@ struct m_can_classdev {
int pm_clock_support;
int is_peripheral;
+ struct m_can_mraminit mraminit_sys; /* mraminit via syscon regmap */
struct mram_cfg mcfg[MRAM_CFG_NUM];
};
--
2.17.1
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