From: Duncan Laurie <dlau...@google.com>

In order to allow this code to be re-used, remove the dependency
on the rest of the cros_ec code from the cros_ec_lpc_mec functions.

Instead of using a hardcoded register base address of 0x800 have
this be passed in to cros_ec_lpc_mec_init().  The existing cros_ec
use case now passes in the 0x800 base address this way.

Signed-off-by: Duncan Laurie <dlau...@google.com>
Signed-off-by: Nick Crews <ncr...@google.com>
---

 drivers/platform/chrome/cros_ec_lpc_mec.c | 54 +++++++++++++++++++----
 drivers/platform/chrome/cros_ec_lpc_mec.h | 45 +++++++++++--------
 drivers/platform/chrome/cros_ec_lpc_reg.c | 43 +++++-------------
 3 files changed, 85 insertions(+), 57 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_lpc_mec.c 
b/drivers/platform/chrome/cros_ec_lpc_mec.c
index c4edfa83e493..18bd9f82be6c 100644
--- a/drivers/platform/chrome/cros_ec_lpc_mec.c
+++ b/drivers/platform/chrome/cros_ec_lpc_mec.c
@@ -24,6 +24,7 @@
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/mfd/cros_ec_commands.h>
+#include <linux/mfd/cros_ec_lpc_mec.h>
 #include <linux/mutex.h>
 #include <linux/types.h>
 
@@ -34,6 +35,7 @@
  * EC mutex because memmap data may be accessed without it being held.
  */
 static struct mutex io_mutex;
+static u16 mec_emi_base, mec_emi_end;
 
 /*
  * cros_ec_lpc_mec_emi_write_address
@@ -46,10 +48,39 @@ static struct mutex io_mutex;
 static void cros_ec_lpc_mec_emi_write_address(u16 addr,
                        enum cros_ec_lpc_mec_emi_access_mode access_type)
 {
-       /* Address relative to start of EMI range */
-       addr -= MEC_EMI_RANGE_START;
-       outb((addr & 0xfc) | access_type, MEC_EMI_EC_ADDRESS_B0);
-       outb((addr >> 8) & 0x7f, MEC_EMI_EC_ADDRESS_B1);
+       outb((addr & 0xfc) | access_type, MEC_EMI_EC_ADDRESS_B0(mec_emi_base));
+       outb((addr >> 8) & 0x7f, MEC_EMI_EC_ADDRESS_B1(mec_emi_base));
+}
+
+/*
+ * cros_ec_lpc_mec_in_range
+ *
+ * Determine if requested addresses are in MEC EMI range.
+ *
+ * @offset:      Address offset
+ * @length: Number of bytes to check
+ *
+ * @return 1 if in range, 0 if not, and -1 if there is an error
+ *         such as the mec range not being initialized
+ */
+int cros_ec_lpc_mec_in_range(unsigned int offset, unsigned int length)
+{
+       if (length == 0)
+               return -1;
+
+       if (WARN_ON(mec_emi_base == 0 || mec_emi_end == 0))
+               return -1;
+
+       if (offset >= mec_emi_base && offset < mec_emi_end) {
+               if (WARN_ON(offset + length - 1 <= mec_emi_end))
+                       return -1;
+               return 1;
+       }
+
+       if (WARN_ON(offset + length > mec_emi_base && offset < mec_emi_end))
+               return -1;
+
+       return 0;
 }
 
 /*
@@ -71,6 +102,11 @@ u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type 
io_type,
        u8 sum = 0;
        enum cros_ec_lpc_mec_emi_access_mode access, new_access;
 
+       /* Return checksum of 0 if window is not initialized */
+       WARN_ON(mec_emi_base == 0 || mec_emi_end == 0);
+       if (mec_emi_base == 0 || mec_emi_end == 0)
+               return 0;
+
        /*
         * Long access cannot be used on misaligned data since reading B0 loads
         * the data register and writing B3 flushes.
@@ -86,9 +122,9 @@ u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type 
io_type,
        cros_ec_lpc_mec_emi_write_address(offset, access);
 
        /* Skip bytes in case of misaligned offset */
-       io_addr = MEC_EMI_EC_DATA_B0 + (offset & 0x3);
+       io_addr = MEC_EMI_EC_DATA_B0(mec_emi_base) + (offset & 0x3);
        while (i < length) {
-               while (io_addr <= MEC_EMI_EC_DATA_B3) {
+               while (io_addr <= MEC_EMI_EC_DATA_B3(mec_emi_base)) {
                        if (io_type == MEC_IO_READ)
                                buf[i] = inb(io_addr++);
                        else
@@ -118,7 +154,7 @@ u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type 
io_type,
                }
 
                /* Access [B0, B3] on each loop pass */
-               io_addr = MEC_EMI_EC_DATA_B0;
+               io_addr = MEC_EMI_EC_DATA_B0(mec_emi_base);
        }
 
 done:
@@ -128,9 +164,11 @@ u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type 
io_type,
 }
 EXPORT_SYMBOL(cros_ec_lpc_io_bytes_mec);
 
-void cros_ec_lpc_mec_init(void)
+void cros_ec_lpc_mec_init(unsigned int base, unsigned int end)
 {
        mutex_init(&io_mutex);
+       mec_emi_base = base;
+       mec_emi_end = end;
 }
 EXPORT_SYMBOL(cros_ec_lpc_mec_init);
 
diff --git a/drivers/platform/chrome/cros_ec_lpc_mec.h 
b/drivers/platform/chrome/cros_ec_lpc_mec.h
index 105068c0e919..a81cc6a8b621 100644
--- a/drivers/platform/chrome/cros_ec_lpc_mec.h
+++ b/drivers/platform/chrome/cros_ec_lpc_mec.h
@@ -24,8 +24,6 @@
 #ifndef __CROS_EC_LPC_MEC_H
 #define __CROS_EC_LPC_MEC_H
 
-#include <linux/mfd/cros_ec_commands.h>
-
 enum cros_ec_lpc_mec_emi_access_mode {
        /* 8-bit access */
        ACCESS_TYPE_BYTE = 0x0,
@@ -45,35 +43,46 @@ enum cros_ec_lpc_mec_io_type {
        MEC_IO_WRITE,
 };
 
-/* Access IO ranges 0x800 thru 0x9ff using EMI interface instead of LPC */
-#define MEC_EMI_RANGE_START EC_HOST_CMD_REGION0
-#define MEC_EMI_RANGE_END   (EC_LPC_ADDR_MEMMAP + EC_MEMMAP_SIZE)
-
 /* EMI registers are relative to base */
-#define MEC_EMI_BASE 0x800
-#define MEC_EMI_HOST_TO_EC (MEC_EMI_BASE + 0)
-#define MEC_EMI_EC_TO_HOST (MEC_EMI_BASE + 1)
-#define MEC_EMI_EC_ADDRESS_B0 (MEC_EMI_BASE + 2)
-#define MEC_EMI_EC_ADDRESS_B1 (MEC_EMI_BASE + 3)
-#define MEC_EMI_EC_DATA_B0 (MEC_EMI_BASE + 4)
-#define MEC_EMI_EC_DATA_B1 (MEC_EMI_BASE + 5)
-#define MEC_EMI_EC_DATA_B2 (MEC_EMI_BASE + 6)
-#define MEC_EMI_EC_DATA_B3 (MEC_EMI_BASE + 7)
+#define MEC_EMI_HOST_TO_EC(MEC_EMI_BASE)       (MEC_EMI_BASE + 0)
+#define MEC_EMI_EC_TO_HOST(MEC_EMI_BASE)       (MEC_EMI_BASE + 1)
+#define MEC_EMI_EC_ADDRESS_B0(MEC_EMI_BASE)    (MEC_EMI_BASE + 2)
+#define MEC_EMI_EC_ADDRESS_B1(MEC_EMI_BASE)    (MEC_EMI_BASE + 3)
+#define MEC_EMI_EC_DATA_B0(MEC_EMI_BASE)       (MEC_EMI_BASE + 4)
+#define MEC_EMI_EC_DATA_B1(MEC_EMI_BASE)       (MEC_EMI_BASE + 5)
+#define MEC_EMI_EC_DATA_B2(MEC_EMI_BASE)       (MEC_EMI_BASE + 6)
+#define MEC_EMI_EC_DATA_B3(MEC_EMI_BASE)       (MEC_EMI_BASE + 7)
 
-/*
+/**
  * cros_ec_lpc_mec_init
  *
  * Initialize MEC I/O.
+ *
+ * @base: MEC EMI Base address
+ * @end:  MEC EMI End address
  */
-void cros_ec_lpc_mec_init(void);
+void cros_ec_lpc_mec_init(unsigned int base, unsigned int end);
 
-/*
+/**
  * cros_ec_lpc_mec_destroy
  *
  * Cleanup MEC I/O.
  */
 void cros_ec_lpc_mec_destroy(void);
 
+/**
+ * cros_ec_lpc_mec_in_range
+ *
+ * Determine if requested addresses are in MEC EMI range.
+ *
+ * @offset: Address offset
+ * @length: Number of bytes to check
+ *
+ * @return 1 if in range, 0 if not, and -1 if there is an error
+ *         such as the mec range not being initialized
+ */
+int cros_ec_lpc_mec_in_range(unsigned int offset, unsigned int length);
+
 /**
  * cros_ec_lpc_io_bytes_mec - Read / write bytes to MEC EMI port
  *
diff --git a/drivers/platform/chrome/cros_ec_lpc_reg.c 
b/drivers/platform/chrome/cros_ec_lpc_reg.c
index fc23d535c404..4cba259b5b1e 100644
--- a/drivers/platform/chrome/cros_ec_lpc_reg.c
+++ b/drivers/platform/chrome/cros_ec_lpc_reg.c
@@ -59,51 +59,32 @@ static u8 lpc_write_bytes(unsigned int offset, unsigned int 
length, u8 *msg)
 
 u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest)
 {
-       if (length == 0)
-               return 0;
-
-       /* Access desired range through EMI interface */
-       if (offset >= MEC_EMI_RANGE_START && offset <= MEC_EMI_RANGE_END) {
-               /* Ensure we don't straddle EMI region */
-               if (WARN_ON(offset + length - 1 > MEC_EMI_RANGE_END))
-                       return 0;
+       int in_range = cros_ec_lpc_mec_in_range(offset, length);
 
-               return cros_ec_lpc_io_bytes_mec(MEC_IO_READ, offset, length,
-                                               dest);
-       }
-
-       if (WARN_ON(offset + length > MEC_EMI_RANGE_START &&
-                   offset < MEC_EMI_RANGE_START))
+       if (in_range < 0)
                return 0;
 
-       return lpc_read_bytes(offset, length, dest);
+       return in_range ?
+               cros_ec_lpc_io_bytes_mec(MEC_IO_READ, offset, length, dest) :
+               lpc_read_bytes(offset, length, dest);
 }
 
 u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg)
 {
-       if (length == 0)
-               return 0;
-
-       /* Access desired range through EMI interface */
-       if (offset >= MEC_EMI_RANGE_START && offset <= MEC_EMI_RANGE_END) {
-               /* Ensure we don't straddle EMI region */
-               if (WARN_ON(offset + length - 1 > MEC_EMI_RANGE_END))
-                       return 0;
+       int in_range = cros_ec_lpc_mec_in_range(offset, length);
 
-               return cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, offset, length,
-                                               msg);
-       }
-
-       if (WARN_ON(offset + length > MEC_EMI_RANGE_START &&
-                   offset < MEC_EMI_RANGE_START))
+       if (in_range < 0)
                return 0;
 
-       return lpc_write_bytes(offset, length, msg);
+       return in_range ?
+               cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, offset, length, msg) :
+               lpc_write_bytes(offset, length, msg);
 }
 
 void cros_ec_lpc_reg_init(void)
 {
-       cros_ec_lpc_mec_init();
+       cros_ec_lpc_mec_init(EC_HOST_CMD_REGION0,
+                            EC_LPC_ADDR_MEMMAP + EC_MEMMAP_SIZE);
 }
 
 void cros_ec_lpc_reg_destroy(void)
-- 
2.20.0.405.gbc1bbc6f85-goog

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