[PATCH 18/43] drm/amdgpu: Fix Vega20 I2C to be agnostic (v2)
Luben Tuikov
luben.tuikov at amd.com
Mon Jun 21 17:11:56 UTC 2021
Teach Vega20 I2C to be agnostic. Allow addressing
different devices while the master holds the bus.
Set STOP as per the controller's specification.
v2: Qualify generating ReSTART before the 1st byte
of the message, when set by the caller, as
those functions are separated, as caught by
Andrey G.
Cc: Jean Delvare <jdelvare at suse.de>
Cc: Alexander Deucher <Alexander.Deucher at amd.com>
Cc: Andrey Grodzovsky <Andrey.Grodzovsky at amd.com>
Cc: Lijo Lazar <Lijo.Lazar at amd.com>
Cc: Stanley Yang <Stanley.Yang at amd.com>
Cc: Hawking Zhang <Hawking.Zhang at amd.com>
Signed-off-by: Luben Tuikov <luben.tuikov at amd.com>
Acked-by: Alexander Deucher <Alexander.Deucher at amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c | 4 +-
drivers/gpu/drm/amd/amdgpu/smu_v11_0_i2c.c | 105 +++++++++++++--------
2 files changed, 69 insertions(+), 40 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c
index fe0e9b0c4d5a38..d02ea083a6c69b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c
@@ -41,10 +41,10 @@ int amdgpu_eeprom_xfer(struct i2c_adapter *i2c_adap,
},
{
.addr = slave_addr,
- .flags = read ? I2C_M_RD: 0,
+ .flags = read ? I2C_M_RD : 0,
.len = bytes,
.buf = eeprom_buf,
- }
+ },
};
int r;
diff --git a/drivers/gpu/drm/amd/amdgpu/smu_v11_0_i2c.c b/drivers/gpu/drm/amd/amdgpu/smu_v11_0_i2c.c
index 5a90d9351b22eb..b8d6d308fb06a0 100644
--- a/drivers/gpu/drm/amd/amdgpu/smu_v11_0_i2c.c
+++ b/drivers/gpu/drm/amd/amdgpu/smu_v11_0_i2c.c
@@ -41,9 +41,7 @@
#define I2C_SW_TIMEOUT 8
#define I2C_ABORT 0x10
-/* I2C transaction flags */
-#define I2C_NO_STOP 1
-#define I2C_RESTART 2
+#define I2C_X_RESTART BIT(31)
#define to_amdgpu_device(x) (container_of(x, struct amdgpu_device, pm.smu_i2c))
@@ -205,9 +203,6 @@ static uint32_t smu_v11_0_i2c_poll_rx_status(struct i2c_adapter *control)
return ret;
}
-
-
-
/**
* smu_v11_0_i2c_transmit - Send a block of data over the I2C bus to a slave device.
*
@@ -252,21 +247,22 @@ static uint32_t smu_v11_0_i2c_transmit(struct i2c_adapter *control,
reg = RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_STATUS);
if (REG_GET_FIELD(reg, CKSVII2C_IC_STATUS, TFNF)) {
do {
- reg = 0;
- /*
- * Prepare transaction, no need to set RESTART. I2C engine will send
- * START as soon as it sees data in TXFIFO
- */
- if (bytes_sent == 0)
- reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, RESTART,
- (i2c_flag & I2C_RESTART) ? 1 : 0);
reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, DAT, data[bytes_sent]);
- /* determine if we need to send STOP bit or not */
- if (numbytes == 1)
- /* Final transaction, so send stop unless I2C_NO_STOP */
- reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, STOP,
- (i2c_flag & I2C_NO_STOP) ? 0 : 1);
+ /* Final message, final byte, must
+ * generate a STOP, to release the
+ * bus, i.e. don't hold SCL low.
+ */
+ if (numbytes == 1 && i2c_flag & I2C_M_STOP)
+ reg = REG_SET_FIELD(reg,
+ CKSVII2C_IC_DATA_CMD,
+ STOP, 1);
+
+ if (bytes_sent == 0 && i2c_flag & I2C_X_RESTART)
+ reg = REG_SET_FIELD(reg,
+ CKSVII2C_IC_DATA_CMD,
+ RESTART, 1);
+
/* Write */
reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, CMD, 0);
WREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_DATA_CMD, reg);
@@ -341,23 +337,21 @@ static uint32_t smu_v11_0_i2c_receive(struct i2c_adapter *control,
smu_v11_0_i2c_clear_status(control);
-
/* Prepare transaction */
-
- /* Each time we disable I2C, so this is not a restart */
- if (bytes_received == 0)
- reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, RESTART,
- (i2c_flag & I2C_RESTART) ? 1 : 0);
-
reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, DAT, 0);
/* Read */
reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, CMD, 1);
- /* Transmitting last byte */
- if (numbytes == 1)
- /* Final transaction, so send stop if requested */
- reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, STOP,
- (i2c_flag & I2C_NO_STOP) ? 0 : 1);
+ /* Final message, final byte, must generate a STOP
+ * to release the bus, i.e. don't hold SCL low.
+ */
+ if (numbytes == 1 && i2c_flag & I2C_M_STOP)
+ reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD,
+ STOP, 1);
+
+ if (bytes_received == 0 && i2c_flag & I2C_X_RESTART)
+ reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD,
+ RESTART, 1);
WREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_DATA_CMD, reg);
@@ -591,23 +585,59 @@ static const struct i2c_lock_operations smu_v11_0_i2c_i2c_lock_ops = {
};
static int smu_v11_0_i2c_xfer(struct i2c_adapter *i2c_adap,
- struct i2c_msg *msgs, int num)
+ struct i2c_msg *msg, int num)
{
int i, ret;
+ u16 addr, dir;
smu_v11_0_i2c_init(i2c_adap);
+ /* From the client's point of view, this sequence of
+ * messages-- the array i2c_msg *msg, is a single transaction
+ * on the bus, starting with START and ending with STOP.
+ *
+ * The client is welcome to send any sequence of messages in
+ * this array, as processing under this function here is
+ * striving to be agnostic.
+ *
+ * Record the first address and direction we see. If either
+ * changes for a subsequent message, generate ReSTART. The
+ * DW_apb_i2c databook, v1.21a, specifies that ReSTART is
+ * generated when the direction changes, with the default IP
+ * block parameter settings, but it doesn't specify if ReSTART
+ * is generated when the address changes (possibly...). We
+ * don't rely on the default IP block parameter settings as
+ * the block is shared and they may change.
+ */
+ if (num > 0) {
+ addr = msg[0].addr;
+ dir = msg[0].flags & I2C_M_RD;
+ }
+
for (i = 0; i < num; i++) {
- uint32_t i2c_flag = ((msgs[i].flags & I2C_M_NOSTART) ? 0 : I2C_RESTART) ||
- (((msgs[i].flags & I2C_M_STOP) ? 0 : I2C_NO_STOP));
+ u32 i2c_flag = 0;
- if (msgs[i].flags & I2C_M_RD)
+ if (msg[i].addr != addr || (msg[i].flags ^ dir) & I2C_M_RD) {
+ addr = msg[i].addr;
+ dir = msg[i].flags & I2C_M_RD;
+ i2c_flag |= I2C_X_RESTART;
+ }
+
+ if (i == num - 1) {
+ /* Set the STOP bit on the last message, so
+ * that the IP block generates a STOP after
+ * the last byte of the message.
+ */
+ i2c_flag |= I2C_M_STOP;
+ }
+
+ if (msg[i].flags & I2C_M_RD)
ret = smu_v11_0_i2c_read_data(i2c_adap,
- msgs + i,
+ msg + i,
i2c_flag);
else
ret = smu_v11_0_i2c_write_data(i2c_adap,
- msgs + i,
+ msg + i,
i2c_flag);
if (ret != I2C_OK) {
@@ -625,7 +655,6 @@ static u32 smu_v11_0_i2c_func(struct i2c_adapter *adap)
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
-
static const struct i2c_algorithm smu_v11_0_i2c_algo = {
.master_xfer = smu_v11_0_i2c_xfer,
.functionality = smu_v11_0_i2c_func,
--
2.32.0
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