[PATCH] i2c:octeon:Add block-mode r/w

From: Aryan Srivastava
Date: Wed Aug 16 2023 - 19:13:42 EST

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Add support for block mode read/write operations on
Thunderx chips.

When attempting r/w operations of greater then 8 bytes
block mode is used, instead of performing a series of
8 byte reads.

Signed-off-by: Aryan Srivastava <aryan.srivastava@xxxxxxxxxxxxxxxxxxx>
---

Hi Andi,
I have re-ran the patch through checkpatch --strict and changed the
comments

Thanks,
Aryan

Changes in v2:
- comment style and formatting.

drivers/i2c/busses/i2c-octeon-core.c | 162 ++++++++++++++++++++++-
drivers/i2c/busses/i2c-octeon-core.h | 14 ++
drivers/i2c/busses/i2c-thunderx-pcidrv.c | 4 +
3 files changed, 174 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-octeon-core.c b/drivers/i2c/busses/i2c-octeon-core.c
index 845eda70b8ca..27a7f61f575b 100644
--- a/drivers/i2c/busses/i2c-octeon-core.c
+++ b/drivers/i2c/busses/i2c-octeon-core.c
@@ -130,6 +130,24 @@ static void octeon_i2c_hlc_disable(struct octeon_i2c *i2c)
octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
}

+static void octeon_i2c_block_enable(struct octeon_i2c *i2c)
+{
+ if (i2c->block_enabled || !TWSI_BLOCK_CTL(i2c))
+ return;
+
+ i2c->block_enabled = true;
+ octeon_i2c_writeq_flush(TWSI_MODE_STRETCH
+ | TWSI_MODE_BLOCK_MODE, i2c->twsi_base + TWSI_MODE(i2c));
+}
+
+static void octeon_i2c_block_disable(struct octeon_i2c *i2c)
+{
+ if (!i2c->block_enabled || !TWSI_BLOCK_CTL(i2c))
+ return;
+
+ i2c->block_enabled = false;
+ octeon_i2c_writeq_flush(TWSI_MODE_STRETCH, i2c->twsi_base + TWSI_MODE(i2c));
+}
/**
* octeon_i2c_hlc_wait - wait for an HLC operation to complete
* @i2c: The struct octeon_i2c
@@ -268,6 +286,7 @@ static int octeon_i2c_start(struct octeon_i2c *i2c)
u8 stat;

octeon_i2c_hlc_disable(i2c);
+ octeon_i2c_block_disable(i2c);

octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_STA);
ret = octeon_i2c_wait(i2c);
@@ -594,6 +613,128 @@ static int octeon_i2c_hlc_comp_write(struct octeon_i2c *i2c, struct i2c_msg *msg
return ret;
}

+/* high-level-controller composite block write+read, m[0]len<=2, m[1]len<=1024 */
+static int octeon_i2c_hlc_block_comp_read(struct octeon_i2c *i2c, struct i2c_msg *msgs)
+{
+ int i, j, len, ret = 0;
+ u64 cmd, rd;
+
+ octeon_i2c_hlc_enable(i2c);
+ octeon_i2c_block_enable(i2c);
+
+ len = msgs[1].len - 1;
+ /* Prepare core command */
+ cmd = SW_TWSI_V | SW_TWSI_R | SW_TWSI_SOVR;
+ /* SIZE */
+ octeon_i2c_writeq_flush((u64)(len), i2c->twsi_base + TWSI_BLOCK_CTL(i2c));
+ /* ADDR */
+ cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT;
+
+ if (msgs[0].flags & I2C_M_TEN)
+ cmd |= SW_TWSI_OP_10_IA;
+ else
+ cmd |= SW_TWSI_OP_7_IA;
+
+ if (msgs[0].len == 2) {
+ u64 ext = 0;
+
+ cmd |= SW_TWSI_EIA;
+ ext = (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT;
+ cmd |= (u64)msgs[0].buf[1] << SW_TWSI_IA_SHIFT;
+ octeon_i2c_writeq_flush(ext, i2c->twsi_base + SW_TWSI_EXT(i2c));
+ } else {
+ cmd |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT;
+ }
+
+ /* Send command to core (send data to FIFO) */
+ octeon_i2c_hlc_int_clear(i2c);
+ octeon_i2c_writeq_flush(cmd, i2c->twsi_base + SW_TWSI(i2c));
+
+ /* Wait for transaction to complete */
+ ret = octeon_i2c_hlc_wait(i2c);
+ if (ret)
+ goto err;
+
+ cmd = __raw_readq(i2c->twsi_base + SW_TWSI(i2c));
+ if ((cmd & SW_TWSI_R) == 0)
+ return octeon_i2c_check_status(i2c, false);
+
+ /* read data in FIFO */
+ octeon_i2c_writeq_flush(TWSI_BLOCK_STS_RESET_PTR, i2c->twsi_base + TWSI_BLOCK_STS(i2c));
+ for (i = 0; i < len; i += 8) {
+ rd = __raw_readq(i2c->twsi_base + TWSI_BLOCK_FIFO(i2c));
+ for (j = 7; j >= 0; j--)
+ msgs[1].buf[i + (7 - j)] = (rd >> (8 * j)) & 0xff;
+ }
+
+ octeon_i2c_block_disable(i2c);
+
+err:
+ return ret;
+}
+
+/* high-level-controller composite block write+write, m[0]len<=2, m[1]len<=1024 */
+static int octeon_i2c_hlc_block_comp_write(struct octeon_i2c *i2c, struct i2c_msg *msgs)
+{
+ bool set_ext = false;
+ int i, j, len, ret = 0;
+ u64 cmd, buf = 0, ext = 0;
+
+ octeon_i2c_hlc_enable(i2c);
+ octeon_i2c_block_enable(i2c);
+
+ len = msgs[1].len - 1;
+ /* Prepare core command */
+ cmd = SW_TWSI_V | SW_TWSI_SOVR;
+ /* SIZE */
+ octeon_i2c_writeq_flush((u64)(len), i2c->twsi_base + TWSI_BLOCK_CTL(i2c));
+ /* ADDR */
+ cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT;
+
+ if (msgs[0].flags & I2C_M_TEN)
+ cmd |= SW_TWSI_OP_10_IA;
+ else
+ cmd |= SW_TWSI_OP_7_IA;
+
+ if (msgs[0].len == 2) {
+ cmd |= SW_TWSI_EIA;
+ ext |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT;
+ set_ext = true;
+ cmd |= (u64)msgs[0].buf[1] << SW_TWSI_IA_SHIFT;
+ } else {
+ cmd |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT;
+ }
+
+ /* Write msg into FIFO buffer */
+ octeon_i2c_writeq_flush(TWSI_BLOCK_STS_RESET_PTR, i2c->twsi_base + TWSI_BLOCK_STS(i2c));
+ for (i = 0; i < len; i += 8) {
+ buf = 0;
+ for (j = 7; j >= 0; j--)
+ buf |= (msgs[1].buf[i + (7 - j)] << (8 * j));
+ octeon_i2c_writeq_flush(buf, i2c->twsi_base + TWSI_BLOCK_FIFO(i2c));
+ }
+ if (set_ext)
+ octeon_i2c_writeq_flush(ext, i2c->twsi_base + SW_TWSI_EXT(i2c));
+
+ /* Send command to core (send data in FIFO) */
+ octeon_i2c_hlc_int_clear(i2c);
+ octeon_i2c_writeq_flush(cmd, i2c->twsi_base + SW_TWSI(i2c));
+
+ /* Wait for transaction to complete */
+ ret = octeon_i2c_hlc_wait(i2c);
+ if (ret)
+ goto err;
+
+ cmd = __raw_readq(i2c->twsi_base + SW_TWSI(i2c));
+ if ((cmd & SW_TWSI_R) == 0)
+ return octeon_i2c_check_status(i2c, false);
+
+ octeon_i2c_block_disable(i2c);
+
+err:
+ return ret;
+}
+
/**
* octeon_i2c_xfer - The driver's master_xfer function
* @adap: Pointer to the i2c_adapter structure
@@ -619,13 +760,21 @@ int octeon_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
if ((msgs[0].flags & I2C_M_RD) == 0 &&
(msgs[1].flags & I2C_M_RECV_LEN) == 0 &&
msgs[0].len > 0 && msgs[0].len <= 2 &&
- msgs[1].len > 0 && msgs[1].len <= 8 &&
+ msgs[1].len > 0 &&
msgs[0].addr == msgs[1].addr) {
- if (msgs[1].flags & I2C_M_RD)
- ret = octeon_i2c_hlc_comp_read(i2c, msgs);
- else
- ret = octeon_i2c_hlc_comp_write(i2c, msgs);
- goto out;
+ if (msgs[1].len <= 8) {
+ if (msgs[1].flags & I2C_M_RD)
+ ret = octeon_i2c_hlc_comp_read(i2c, msgs);
+ else
+ ret = octeon_i2c_hlc_comp_write(i2c, msgs);
+ goto out;
+ } else if (msgs[1].len <= 1024 && TWSI_BLOCK_CTL(i2c)) {
+ if (msgs[1].flags & I2C_M_RD)
+ ret = octeon_i2c_hlc_block_comp_read(i2c, msgs);
+ else
+ ret = octeon_i2c_hlc_block_comp_write(i2c, msgs);
+ goto out;
+ }
}
}

@@ -720,6 +869,7 @@ int octeon_i2c_init_lowlevel(struct octeon_i2c *i2c)
/* toggle twice to force both teardowns */
octeon_i2c_hlc_enable(i2c);
octeon_i2c_hlc_disable(i2c);
+
return 0;
}

diff --git a/drivers/i2c/busses/i2c-octeon-core.h b/drivers/i2c/busses/i2c-octeon-core.h
index 9bb9f64fdda0..b889ecf9968d 100644
--- a/drivers/i2c/busses/i2c-octeon-core.h
+++ b/drivers/i2c/busses/i2c-octeon-core.h
@@ -85,6 +85,11 @@
#define TWSI_INT_SDA BIT_ULL(10)
#define TWSI_INT_SCL BIT_ULL(11)

+#define TWSI_MODE_STRETCH BIT_ULL(1)
+#define TWSI_MODE_BLOCK_MODE BIT_ULL(2)
+
+#define TWSI_BLOCK_STS_RESET_PTR BIT_ULL(0)
+#define TWSI_BLOCK_STS_BUSY BIT_ULL(1)
#define I2C_OCTEON_EVENT_WAIT 80 /* microseconds */

/* Register offsets */
@@ -92,11 +97,19 @@ struct octeon_i2c_reg_offset {
unsigned int sw_twsi;
unsigned int twsi_int;
unsigned int sw_twsi_ext;
+ unsigned int twsi_mode;
+ unsigned int twsi_block_ctl;
+ unsigned int twsi_block_sts;
+ unsigned int twsi_block_fifo;
};

#define SW_TWSI(x) (x->roff.sw_twsi)
#define TWSI_INT(x) (x->roff.twsi_int)
#define SW_TWSI_EXT(x) (x->roff.sw_twsi_ext)
+#define TWSI_MODE(x) (x->roff.twsi_mode)
+#define TWSI_BLOCK_CTL(x) (x->roff.twsi_block_ctl)
+#define TWSI_BLOCK_STS(x) (x->roff.twsi_block_sts)
+#define TWSI_BLOCK_FIFO(x) (x->roff.twsi_block_fifo)

struct octeon_i2c {
wait_queue_head_t queue;
@@ -110,6 +123,7 @@ struct octeon_i2c {
void __iomem *twsi_base;
struct device *dev;
bool hlc_enabled;
+ bool block_enabled;
bool broken_irq_mode;
bool broken_irq_check;
void (*int_enable)(struct octeon_i2c *);
diff --git a/drivers/i2c/busses/i2c-thunderx-pcidrv.c b/drivers/i2c/busses/i2c-thunderx-pcidrv.c
index a77cd86fe75e..abde98117d7e 100644
--- a/drivers/i2c/busses/i2c-thunderx-pcidrv.c
+++ b/drivers/i2c/busses/i2c-thunderx-pcidrv.c
@@ -165,6 +165,10 @@ static int thunder_i2c_probe_pci(struct pci_dev *pdev,
i2c->roff.sw_twsi = 0x1000;
i2c->roff.twsi_int = 0x1010;
i2c->roff.sw_twsi_ext = 0x1018;
+ i2c->roff.twsi_mode = 0x1038;
+ i2c->roff.twsi_block_ctl = 0x1048;
+ i2c->roff.twsi_block_sts = 0x1050;
+ i2c->roff.twsi_block_fifo = 0x1058;

i2c->dev = dev;
pci_set_drvdata(pdev, i2c);
--
2.41.0

Next message: Alexandre Belloni: "Re: [PATCH] rtc: da9063: Mark the alarm IRQ as a wake IRQ"
Previous message: Alexandre Belloni: "Re: [RESEND PATCH v2] rtc: pcf2127: add error checking when disabling POR0"
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