[RFC 06/47] mtd: nand: stm_nand_bch: change between BCH and Hamming modes

Lee Jones
2014-03-25T08:21:26Z

The EMISS is a device which, amongst other things, controls various
flash memory modes. We make use of it here merely to flip the
HAMMING_NOT_BCH bit dependant on whether we wish to operate in Hamming
or BCH modes. The STM BCH driver makes good use of the helper introduced
here.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
include/linux/mtd/stm_nand.h | 42 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)

diff --git a/include/linux/mtd/stm_nand.h b/include/linux/mtd/stm_nand.h
index 9210d5c..da2006c 100644
--- a/include/linux/mtd/stm_nand.h
+++ b/include/linux/mtd/stm_nand.h
@@ -15,6 +15,8 @@
#ifndef __LINUX_STM_NAND_H
#define __LINUX_STM_NAND_H

+#include <linux/io.h>
+
struct stm_plat_nand_bch_data {
struct stm_nand_bank_data *bank;
enum stm_nand_bch_ecc_config bch_ecc_cfg;
@@ -30,4 +32,44 @@ struct stm_plat_nand_bch_data {
bool flashss;
};

+#define EMISS_BASE 0xfef01000
+#define EMISS_CONFIG 0x0000
+#define EMISS_CONFIG_HAMMING_NOT_BCH (0x1 << 6)
+
+enum nandi_controllers {
+ STM_NANDI_UNCONFIGURED,
+ STM_NANDI_HAMMING,
+ STM_NANDI_BCH
+};
+
+static inline void emiss_nandi_select(enum nandi_controllers controller)
+{
+ unsigned v;
+ void __iomem *emiss_config_base;
+
+ emiss_config_base = ioremap(EMISS_BASE, 4);
+ if (!emiss_config_base) {
+ pr_err("%s: failed to ioremap EMISS\n", __func__);
+ return;
+ }
+
+ v = readl(emiss_config_base + EMISS_CONFIG);
+
+ if (controller == STM_NANDI_HAMMING) {
+ if (v & EMISS_CONFIG_HAMMING_NOT_BCH)
+ goto out;
+ v |= EMISS_CONFIG_HAMMING_NOT_BCH;
+ } else {
+ if (!(v & EMISS_CONFIG_HAMMING_NOT_BCH))
+ goto out;
+ v &= ~EMISS_CONFIG_HAMMING_NOT_BCH;
+ }
+
+ writel(v, emiss_config_base + EMISS_CONFIG);
+ readl(emiss_config_base + EMISS_CONFIG);
+
+out:
+ iounmap(emiss_config_base);
+}
+
#endif /* __LINUX_STM_NAND_H */
--
1.8.3.2