From aa6fed90fea20bf52215952b276169efab8ae5ad Mon Sep 17 00:00:00 2001 From: Abel Vesa Date: Wed, 10 Nov 2021 19:46:44 +0200 Subject: [PATCH 1/5] dt-bindings: i2c: imx-lpi2c: Fix i.MX 8QM compatible matching The i.MX 8QM DTS files use two compatibles, so update the binding to fix dtbs_check warnings like: arch/arm64/boot/dts/freescale/imx8qm-mek.dt.yaml: i2c@5a800000: compatible: ['fsl,imx8qm-lpi2c', 'fsl,imx7ulp-lpi2c'] is too long Signed-off-by: Abel Vesa Acked-by: Rob Herring Signed-off-by: Wolfram Sang --- Documentation/devicetree/bindings/i2c/i2c-imx-lpi2c.yaml | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/Documentation/devicetree/bindings/i2c/i2c-imx-lpi2c.yaml b/Documentation/devicetree/bindings/i2c/i2c-imx-lpi2c.yaml index 29b9447f3b84a..fe0c89edf7c10 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-imx-lpi2c.yaml +++ b/Documentation/devicetree/bindings/i2c/i2c-imx-lpi2c.yaml @@ -17,9 +17,10 @@ properties: oneOf: - enum: - fsl,imx7ulp-lpi2c - - fsl,imx8qm-lpi2c - items: - - const: fsl,imx8qxp-lpi2c + - enum: + - fsl,imx8qxp-lpi2c + - fsl,imx8qm-lpi2c - const: fsl,imx7ulp-lpi2c reg: From 9b5bf5878138293fb5b14a48a7a17b6ede6bea25 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Tue, 9 Nov 2021 16:02:57 +0100 Subject: [PATCH 2/5] i2c: i801: Restore INTREN on unload If driver interrupts are enabled, SMBHSTCNT_INTREN will be 1 after the first transaction, and will stay to that value forever. This means that interrupts will be generated for both host-initiated transactions and also SMBus Alert events even after the driver is unloaded. To be on the safe side, we should restore the initial state of this bit at suspend and reboot time, as we do for several other configuration bits already and for the same reason: the BIOS should be handed the device in the same configuration state in which we received it. Otherwise interrupts may be generated which nobody will process. Signed-off-by: Jean Delvare Tested-by: Jarkko Nikula Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-i801.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index 05187457f88a2..ed271274250b1 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -259,6 +259,7 @@ struct i801_priv { struct i2c_adapter adapter; unsigned long smba; unsigned char original_hstcfg; + unsigned char original_hstcnt; unsigned char original_slvcmd; struct pci_dev *pci_dev; unsigned int features; @@ -1805,7 +1806,8 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id) outb_p(inb_p(SMBAUXCTL(priv)) & ~(SMBAUXCTL_CRC | SMBAUXCTL_E32B), SMBAUXCTL(priv)); - /* Remember original Host Notify setting */ + /* Remember original Interrupt and Host Notify settings */ + priv->original_hstcnt = inb_p(SMBHSTCNT(priv)) & ~SMBHSTCNT_KILL; if (priv->features & FEATURE_HOST_NOTIFY) priv->original_slvcmd = inb_p(SMBSLVCMD(priv)); @@ -1869,6 +1871,7 @@ static void i801_remove(struct pci_dev *dev) { struct i801_priv *priv = pci_get_drvdata(dev); + outb_p(priv->original_hstcnt, SMBHSTCNT(priv)); i801_disable_host_notify(priv); i801_del_mux(priv); i2c_del_adapter(&priv->adapter); @@ -1892,6 +1895,7 @@ static void i801_shutdown(struct pci_dev *dev) struct i801_priv *priv = pci_get_drvdata(dev); /* Restore config registers to avoid hard hang on some systems */ + outb_p(priv->original_hstcnt, SMBHSTCNT(priv)); i801_disable_host_notify(priv); pci_write_config_byte(dev, SMBHSTCFG, priv->original_hstcfg); } @@ -1901,6 +1905,7 @@ static int i801_suspend(struct device *dev) { struct i801_priv *priv = dev_get_drvdata(dev); + outb_p(priv->original_hstcnt, SMBHSTCNT(priv)); pci_write_config_byte(priv->pci_dev, SMBHSTCFG, priv->original_hstcfg); return 0; } From 03a976c9afb5e3c4f8260c6c08a27d723b279c92 Mon Sep 17 00:00:00 2001 From: Jarkko Nikula Date: Wed, 17 Nov 2021 11:45:09 +0200 Subject: [PATCH 3/5] i2c: i801: Fix interrupt storm from SMB_ALERT signal Currently interrupt storm will occur from i2c-i801 after first transaction if SMB_ALERT signal is enabled and ever asserted. It is enough if the signal is asserted once even before the driver is loaded and does not recover because that interrupt is not acknowledged. This fix aims to fix it by two ways: - Add acknowledging for the SMB_ALERT interrupt status - Disable the SMB_ALERT interrupt on platforms where possible since the driver currently does not make use for it Acknowledging resets the SMB_ALERT interrupt status on all platforms and also should help to avoid interrupt storm on older platforms where the SMB_ALERT interrupt disabling is not available. For simplicity this fix reuses the host notify feature for disabling and restoring original register value. Link: https://bugzilla.kernel.org/show_bug.cgi?id=177311 Reported-by: ck+kernelbugzilla@bl4ckb0x.de Reported-by: stephane.poignant@protonmail.com Signed-off-by: Jarkko Nikula Reviewed-by: Jean Delvare Tested-by: Jean Delvare Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-i801.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index ed271274250b1..41446f9cc52da 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -191,6 +191,7 @@ #define SMBSLVSTS_HST_NTFY_STS BIT(0) /* Host Notify Command register bits */ +#define SMBSLVCMD_SMBALERT_DISABLE BIT(2) #define SMBSLVCMD_HST_NTFY_INTREN BIT(0) #define STATUS_ERROR_FLAGS (SMBHSTSTS_FAILED | SMBHSTSTS_BUS_ERR | \ @@ -642,12 +643,20 @@ static irqreturn_t i801_isr(int irq, void *dev_id) i801_isr_byte_done(priv); /* - * Clear irq sources and report transaction result. + * Clear remaining IRQ sources: Completion of last command, errors + * and the SMB_ALERT signal. SMB_ALERT status is set after signal + * assertion independently of the interrupt generation being blocked + * or not so clear it always when the status is set. + */ + status &= SMBHSTSTS_INTR | STATUS_ERROR_FLAGS | SMBHSTSTS_SMBALERT_STS; + if (status) + outb_p(status, SMBHSTSTS(priv)); + status &= ~SMBHSTSTS_SMBALERT_STS; /* SMB_ALERT not reported */ + /* + * Report transaction result. * ->status must be cleared before the next transaction is started. */ - status &= SMBHSTSTS_INTR | STATUS_ERROR_FLAGS; if (status) { - outb_p(status, SMBHSTSTS(priv)); priv->status = status; complete(&priv->done); } @@ -975,9 +984,13 @@ static void i801_enable_host_notify(struct i2c_adapter *adapter) if (!(priv->features & FEATURE_HOST_NOTIFY)) return; - if (!(SMBSLVCMD_HST_NTFY_INTREN & priv->original_slvcmd)) - outb_p(SMBSLVCMD_HST_NTFY_INTREN | priv->original_slvcmd, - SMBSLVCMD(priv)); + /* + * Enable host notify interrupt and block the generation of interrupt + * from the SMB_ALERT signal because the driver does not support + * SMBus Alert. + */ + outb_p(SMBSLVCMD_HST_NTFY_INTREN | SMBSLVCMD_SMBALERT_DISABLE | + priv->original_slvcmd, SMBSLVCMD(priv)); /* clear Host Notify bit to allow a new notification */ outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv)); From 84e1d0bf1d7121759622dabf8fbef4c99ad597c5 Mon Sep 17 00:00:00 2001 From: Vincent Whitchurch Date: Thu, 11 Nov 2021 17:04:11 +0100 Subject: [PATCH 4/5] i2c: virtio: disable timeout handling If a timeout is hit, it can result is incorrect data on the I2C bus and/or memory corruptions in the guest since the device can still be operating on the buffers it was given while the guest has freed them. Here is, for example, the start of a slub_debug splat which was triggered on the next transfer after one transfer was forced to timeout by setting a breakpoint in the backend (rust-vmm/vhost-device): BUG kmalloc-1k (Not tainted): Poison overwritten First byte 0x1 instead of 0x6b Allocated in virtio_i2c_xfer+0x65/0x35c age=350 cpu=0 pid=29 __kmalloc+0xc2/0x1c9 virtio_i2c_xfer+0x65/0x35c __i2c_transfer+0x429/0x57d i2c_transfer+0x115/0x134 i2cdev_ioctl_rdwr+0x16a/0x1de i2cdev_ioctl+0x247/0x2ed vfs_ioctl+0x21/0x30 sys_ioctl+0xb18/0xb41 Freed in virtio_i2c_xfer+0x32e/0x35c age=244 cpu=0 pid=29 kfree+0x1bd/0x1cc virtio_i2c_xfer+0x32e/0x35c __i2c_transfer+0x429/0x57d i2c_transfer+0x115/0x134 i2cdev_ioctl_rdwr+0x16a/0x1de i2cdev_ioctl+0x247/0x2ed vfs_ioctl+0x21/0x30 sys_ioctl+0xb18/0xb41 There is no simple fix for this (the driver would have to always create bounce buffers and hold on to them until the device eventually returns the buffers), so just disable the timeout support for now. Fixes: 3cfc88380413d20f ("i2c: virtio: add a virtio i2c frontend driver") Acked-by: Jie Deng Signed-off-by: Vincent Whitchurch Acked-by: Michael S. Tsirkin Reviewed-by: Viresh Kumar Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-virtio.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) diff --git a/drivers/i2c/busses/i2c-virtio.c b/drivers/i2c/busses/i2c-virtio.c index 1ed4daa918a06..95378780da6d6 100644 --- a/drivers/i2c/busses/i2c-virtio.c +++ b/drivers/i2c/busses/i2c-virtio.c @@ -104,11 +104,10 @@ static int virtio_i2c_prepare_reqs(struct virtqueue *vq, static int virtio_i2c_complete_reqs(struct virtqueue *vq, struct virtio_i2c_req *reqs, - struct i2c_msg *msgs, int num, - bool timedout) + struct i2c_msg *msgs, int num) { struct virtio_i2c_req *req; - bool failed = timedout; + bool failed = false; unsigned int len; int i, j = 0; @@ -130,7 +129,7 @@ static int virtio_i2c_complete_reqs(struct virtqueue *vq, j++; } - return timedout ? -ETIMEDOUT : j; + return j; } static int virtio_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, @@ -139,7 +138,6 @@ static int virtio_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, struct virtio_i2c *vi = i2c_get_adapdata(adap); struct virtqueue *vq = vi->vq; struct virtio_i2c_req *reqs; - unsigned long time_left; int count; reqs = kcalloc(num, sizeof(*reqs), GFP_KERNEL); @@ -162,11 +160,9 @@ static int virtio_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, reinit_completion(&vi->completion); virtqueue_kick(vq); - time_left = wait_for_completion_timeout(&vi->completion, adap->timeout); - if (!time_left) - dev_err(&adap->dev, "virtio i2c backend timeout.\n"); + wait_for_completion(&vi->completion); - count = virtio_i2c_complete_reqs(vq, reqs, msgs, count, !time_left); + count = virtio_i2c_complete_reqs(vq, reqs, msgs, count); err_free: kfree(reqs); From bed68f4f4db429a0bf544887e64dc710e5a690ea Mon Sep 17 00:00:00 2001 From: Miquel Raynal Date: Mon, 15 Nov 2021 12:08:18 +0100 Subject: [PATCH 5/5] docs: i2c: smbus-protocol: mention the repeated start condition Sr is a repeated start, it is used in both I2C and SMBus protocols. Provide its description and replace start ("S") conditions with repeated start ("Sr") conditions when relevant. This allows the documentation to match the SMBus specification available at [1]. [1] http://www.smbus.org/specs/SMBus_3_1_20180319.pdf Signed-off-by: Miquel Raynal Signed-off-by: Wolfram Sang --- Documentation/i2c/smbus-protocol.rst | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/Documentation/i2c/smbus-protocol.rst b/Documentation/i2c/smbus-protocol.rst index 9e07e6bbe6a39..00d8e17d0acab 100644 --- a/Documentation/i2c/smbus-protocol.rst +++ b/Documentation/i2c/smbus-protocol.rst @@ -36,6 +36,8 @@ Key to symbols =============== ============================================================= S Start condition +Sr Repeated start condition, used to switch from write to + read mode. P Stop condition Rd/Wr (1 bit) Read/Write bit. Rd equals 1, Wr equals 0. A, NA (1 bit) Acknowledge (ACK) and Not Acknowledge (NACK) bit @@ -100,7 +102,7 @@ Implemented by i2c_smbus_read_byte_data() This reads a single byte from a device, from a designated register. The register is specified through the Comm byte:: - S Addr Wr [A] Comm [A] S Addr Rd [A] [Data] NA P + S Addr Wr [A] Comm [A] Sr Addr Rd [A] [Data] NA P Functionality flag: I2C_FUNC_SMBUS_READ_BYTE_DATA @@ -114,7 +116,7 @@ This operation is very like Read Byte; again, data is read from a device, from a designated register that is specified through the Comm byte. But this time, the data is a complete word (16 bits):: - S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P + S Addr Wr [A] Comm [A] Sr Addr Rd [A] [DataLow] A [DataHigh] NA P Functionality flag: I2C_FUNC_SMBUS_READ_WORD_DATA @@ -164,7 +166,7 @@ This command selects a device register (through the Comm byte), sends 16 bits of data to it, and reads 16 bits of data in return:: S Addr Wr [A] Comm [A] DataLow [A] DataHigh [A] - S Addr Rd [A] [DataLow] A [DataHigh] NA P + Sr Addr Rd [A] [DataLow] A [DataHigh] NA P Functionality flag: I2C_FUNC_SMBUS_PROC_CALL @@ -181,7 +183,7 @@ of data is specified by the device in the Count byte. :: S Addr Wr [A] Comm [A] - S Addr Rd [A] [Count] A [Data] A [Data] A ... A [Data] NA P + Sr Addr Rd [A] [Count] A [Data] A [Data] A ... A [Data] NA P Functionality flag: I2C_FUNC_SMBUS_READ_BLOCK_DATA @@ -212,7 +214,7 @@ This command selects a device register (through the Comm byte), sends 1 to 31 bytes of data to it, and reads 1 to 31 bytes of data in return:: S Addr Wr [A] Comm [A] Count [A] Data [A] ... - S Addr Rd [A] [Count] A [Data] ... A P + Sr Addr Rd [A] [Count] A [Data] ... A P Functionality flag: I2C_FUNC_SMBUS_BLOCK_PROC_CALL @@ -300,7 +302,7 @@ This command reads a block of bytes from a device, from a designated register that is specified through the Comm byte:: S Addr Wr [A] Comm [A] - S Addr Rd [A] [Data] A [Data] A ... A [Data] NA P + Sr Addr Rd [A] [Data] A [Data] A ... A [Data] NA P Functionality flag: I2C_FUNC_SMBUS_READ_I2C_BLOCK